As long as there has been electronics, there has been the problem of how to keep them cool.  Unfortunately, the problem gets more complex the smaller that computers get and what works for one PC might not work for others.  This is clearly the obstacle to overcome when trying to cool down a settop box.  Read more to find out how I was able to pull it off very well for a little over $10 in parts and still maintain all my hair.

It’s pretty synonymous that computers == heat and with any mainstream processor, you have a pretty significantly sized heatsink and fan to keep the processor cool.  While processor fans and heatsinks are pretty easy to come by for standard desktop computers and servers, embedded devices are pretty much left to their own devices (no pun intended).  I was faced with the very same problem when I decided to start using two embedded computers to replace a NAT router and mini home server.   These machines are sold as a “set-top-box” and were initially intended for some kind of Video On Demand service that used broadband service to deliver content.  The computer hardware was figured out and working however left to the “stock” heatsink and heatspreader (there was no fan when I started) the box was very hot to the touch.  I decided to initially tack a case fan to the heatsink to help with the cooling, but that only served to band-aid the problem.

The settop box. Those holes on top are supposed to keep this cool?

A view of the internals left very little room to work with.  There was no way I was going to be able to use a standard computer case fan without some massive case modding. Since I wasn’t really looking for a reason to spend the entire day with the dremel cutting sheet steel, I decided to take a look at what I had to work with.

Settop internals. It's quite cramped in there.

Since this thing was designed to be a set top box, there were all kinds of connections on the back, including a big SCART connector.  According to wikipedia, SCART is primarily a European standard and is very commonplace for connecting AV equipment to TVs and etc.  Since this settop was sold in the US, the SCART connector was unpopulated and instead left a knockout.  This gave me a sizeable aperture for the hot exhaust, now to find some way to get the air moving.

Exhaust Port Location

In the above shot, the SCART port is the large dull steel colored rectangular hole in the silver backing.  The hole is high enough that it does not interfere with the SDRAM sticks and far enough away from the power supply not to be a shock hazard.  Now knowing what I had and how big of a fan I needed, I went to Microcenter and took a look around. They had a lot of normal desktop fans and a few oddball fans and the one that would work best ended up being an old-style squirrelcage fan.  A squirrelcage fan is like the standard case fan that you’re used to however instead of normal blades, the squirrel cage fan uses an impeller that sucks in air from the front and exhausts it out of the side of the fan. The fan exhaust is perpendicular to the intake unlike a standard fan.  The advantage is that a squirrel cage fan offers the airflow of a standard fan in a smaller form factor due to the perpendicular exhaust.  The general idea is that the squirrel cage fan will suck in the warm air from inside the case and exhaust out of the now ex-SCART port.

Squirrel cage blower

This is the squirrelcage fan that I selected. Although I couldn’t find a link on Microcenter’s website, here is a link of a comparable fan. It is a12V fan that is designed to screw into a removed expansion slot blank on a computer case.  The fan connects via a 12VDC Molex connector and is designed to connect between the power cable and a hard drive or CDROM.  Since there are no Molex connectors, I had to also get a three pin cable to connect to the motherboard. Thankfully Microcenter had a clearance on Intel OEM Processor fans and were selling just the connector for 25 cents.

Intel cable and Power header

The Intel cable snaps perfectly into a convenient header that I found on the motherboard.  This will be perfect as if I ever need to replace the squirrelcage fan, I can do so without having to cut up wires and desolder splices.

Now that I had the idea of generally where everything was to go, I had to make some modifications to the steel bracket on the blower. The blower was originally designed to fit in an empty expansion slot and the tab used for securing the blower to the chassis needed to be flattened.

Squirrelcage bracket

The bracket in question is so eloquently highlighted by none other than Duke Nukem.  In order to modify the bracket without destroying the fan in the process, I decided to remove the bracket.  In the above picture, you can see a notch that holds the fan in the bracket.  There are four notches in total, two on each side. I used a couple of flat bladed screwdrivers and gently pried the bracket off.

Bracket removed from fan

After a little bit of  the creative application of force, I finally had the bracket flat enough so that it would not interfere with mounting. (Translation:  I beat the crap out of it with a hammer.)

Flattened Bracket modification

Now that the bracket is flattened enough, it’s time to see about how to go about lining it up with the SCART exhaust port.

SCART holes line up with the grill.

I lucked out on this one.  The two holes that were intended for the SCART interface hardware line up perfectly with two lines on the grill.  This made mounting the bracket as easy as a couple of small nuts and bolts.  Once mounted, it was time to start working on the power cable.  I decided to use the yellow and black wires for the fan’s power because black is considered “ground” and yellow is considered the “+12V” lead in computer power supplies.

Three wire connector

I cut off the green lead, and cut the cable about two inches long.  I then wired the wires from the fan to the Intel cable.  The red wire on the blower goes to the Yellow wire on the Intel cable and the two blacks go together. Not shown in this image is the small length of shrinkwrap used to secure and isolate the connection.

Solder Preperation

After soldering the first wire, I sealed it with the heatshrink and then soldered the other wire.

Soldered and Shrinked

Another piece of heatshrink later and I have a ready to install cable.

Completed cable

With the cable now complete, all that remained was to plug the power cable into the power header and snap the blower back into the bracket.

Blower Mounted

Here is a shot of the back of the case with the now operational blower.

SCART Exhaust port.

And finally, here’s a side-by-side (or top and bottom) with an unmodified settop box.

Modded and Unmodded settops

Final Results

I’ve been running the settop now for the past couple of days and I can say that the blower is 100% effective.  The case is cool to the touch and my fears of cooking the processor have been abated.  The machine will do very nicely as a pfSense firewall as soon as I get around to finishing it up but for now, this is one less thing stopping me from using it.

If you ever find yourself in a similar situation where you have to get airflow but don’t have much space, I highly recommend these squirrelcage blowers.  They’re cheap, they’re effective and well worth the time to install.  Although I had to go a bit out of my way to install the blower, not having to worry about cooking the machine is well worth the effort.

I hope you enjoyed this article, it was definitely an interesting approach to cooling in a small form factor.  Do you have any insight or other experience with odd cooling in a similar situation?  Please leave a comment, I’m always interested in other people’s stories.

Ok, so not long after I published the article on  the hardware teardown of the Seagate Dockstar, I couldn’t help myself  so I started working on things to do with this device.  I did a lot of research in regards to the capabilities of the Dockstar, including being able to push a customized Linux OS on the device.  Once I saw the article at Hackaday that covers exactly how to replace the OS, I knew I had to do it for myself.  There are two ways to perform this upgrade however in order to capture syslog output and to be able to get to the bootloader, a serial port is required.  Just about all of the sites will describe the pins needed to make the connection, however none of them detail how to do it very clearly and none of them address the issue of aesthetics.  Read on for my method of adding a serial port to the Dockstar without affecting the look of the device.

Before We Begin….

The Seagate Dockstar has a serial port available via three of the pins on the header at the front of the PCB.  The issue is that they’re not very easy to get to without having to disassemble the device each and every time you need to do a recovery on it.  This is hardly an ideal solution, and who knows what I’ll be doing with the device in the future.  If I decide to embed the  device and something goes wrong, I’ll have to have access to the serial port in order to debug it.

But, simply having access to the serial port is not enough.  The Dockstar’s aesthetic elegance is in the fact that it’s so simple.  No  massive amount of connectors aside from Power and Ethernet, and with little room to begin with, I don’t want to have a cable hanging out of the box just to have access to the serial port.  After much deliberation, I decided that a pin-row setup would be ideal instead of some other outward-facing connector.  The advantages to a pin-row set up is that there are only as many holes as are needed to establish connection and the connector size is significantly smaller than would be a standard DB-9 connector.  An additional advantage to the pin-row setup is that the connection would be temporary and can be easily removed. The resulting connection port would still be cleanly presented and would not stick out like a sore thumb.

Parts List:

In order to pull this off, you will need the following items:

- a CA-42 USB cable. – This is most commonly sold as a Nokia cable through Amazon and can usually be had for a few bucks. This is required as the dockstar’s serial port voltages are at a 3.3V TTL.  interfacing it to a standard +12V/-12V serial port will damage your Dockstar. The CA-42 cable has a PL-2303 USB to 3.3v TTL serial adapter in it which provides the required 3.3v TTL and gives an easy to use connector for plugging it into your host PC.

- a 4-pin header with long pins. – The pins have to be long enough that they will go through the Dockstar case and into the matched connector securely.

- a matched connector for the 4 pin header. – This will be mounted inside the Dockstar.

- Heat shrink tubing of various sizes. (Use the images as a guide)

- A couple of spares of the 4 pin header and the connector.  (We’ll use one spare for making the holes in the case, but it’s always good to have extras just in case.

Tools List:

- Soldering Iron

- Lighter (for heatshrink)

- small diameter drillbits

- Spudger (or Radio Shack soldering toolkit)

- A Linux machine with an available USB port. Note: It may be possible to use a windows computer for testing however my USB adapter only works in Linux.

Now that you have all the components, it’s important to stop here for a sec and cover the legal mess. It is critically important that you know what you’re doing.  You can not blame me or hold this site responsible (or the maintainers of this site) if you do something and blow up your Dockstar.  Be careful, do your research, check twice, solder once.

Please note that if you have never worked with shrinkwrap, the important thing is to watch the fire and keep it moving.  If you leave the lighter in the same place for too long, the shrinkwrap will stop shrinking and will catch fire.  When in doubt, apply the hat quickly and watch the shrinkwrap closely.   If it does something wrong, move the lighter away and start blowing on it to cool it down.

Part 1:  The Cable

It’s easier to do the modification on the cable first rather than do the Dockstar portion due to the fact that part of performing the Dockstar side of things will require testing to make sure it’s all working properly. So, let’s get started.

CA-42 cable, header and connector

This is the cable that we will be hacking together. The pin-row connector shown above is a 4 pin wirewrap terminal and a push-on style PCB mount connector.

cable header and connector

In the above photo,you can see the long header pins and the matching connector and how they fit together.  Before we get started with modifying the cable, we first need to figure out how it’s wired up.  Because there is a very good chance that you have a generic cable, and generic cables are wired differently, we will start off with spudging the USB connector apart.

Spudger to cable case

Follow the plastic seam of the USB connector with the sharp blade of the spudger.  Gently work the two halves of the plastic apart until you are able to seperate them.  You should see a connector that looks like the one below.

Opened cable

A closer of the PCB will reveal that the  wires (white, blue and green) are labeled for our easy hacking convenience . The three wires in my cable are Blue(GND), Green (RxD), and White (TxD). Now that we know which wire does what, reassemble the USB cable as we will not need to do any work on this end of the cable.  Starting with the 4 pin connector, pick one of the two internal pins and remove it.

Removed pin from connection block

The reason for removing the offset pin is for two reasons.  1) There are only three wires required for connection and 2) The missing pin will allow us to key the connector so that it can’t be reversed.  Going back to the USB cable, cut off the fat Nokia phone end and strip the cable back about an inch.  To help with soldering, insert the long end of the header pins into a block of breadboard.  This will help hold the connection stable while you solder the cable.   You will also need to cut the small diameter shrinkwrap in three sizes as shown below.

Cable preparation

The reason for the three lengths of heatshrink tubing is that we will build up the edge of the cable to a large size so that we can use the larger heatshrink tube  (in the back of the picture) to bind the header pins into the wrap and the wrap to the end of the cable to strengthen the cable.  If you have never worked with heatshrink tubing, it’s very easy to work with.  Start with the longest piece of tubing, and slide it over the cable. Make sure that the cut end matches the end of the insulation and heat with the lighter.  KEEP THE FLAME MOVING ACROSS THE HEATSHRINK!! Once the heatshrink has stopped shrinking, allow it to cool and repeat for each piece.

Shrinkrwrapped cable

This is the end result of the shrinkwrapping.  Now that the end is built up, slide a piece of the large shrink over the end of the cable but do not apply heat just yet. Strip back the individual wires so that you can attach them to the header pins.

Cable prepped for soldering

Now that we’re ready to solder the connector, it’s important to decide how to create the pinout.  In my setup, I elected to have the GND connection by itself, then the TX and RX pins.  For each wire, wrap the wire around the soldering post on the header pins and solder.  Be sure to use only enough solder as is required for the connection and do not  bridge the pins.

Soldered cable to header pins

Now with the cable soldered and the connections solid, it’s time to apply the heat to the large heatshrink.  Very carefully pull the end of the heatshrink over the black plastic header and gently apply heat.  Adjust if needed and let the tubing shrink without it pulling itself off of the header plastic.

Heatshrink applied to header

When you have it this far, go ahead and apply heat to the rest of the heatshrink tubing, making sure not to singe it.  When you are done, you should have a cable looking like the one below.

Completed cable with socket

This was the easy part, Now it’s time for the dockstar.

Part 2: The Dockstar

We’ve got the cable, but without something to connect it to, it’s pretty useless (unless you want to use it on a breadboard).  Let’s take a look at what’s going on.

Dockstar connection planning

Since I’ve already determined that I want the connector for the serial to come out of the back of the device and I’ve already found a suitably small connector, it’s time to find a location where I can attach it without getting too involved or without interfering with the existing ports on the back of the dockstar.  I’ve elected to put the serial port just above the center USB connector.  In the photo above, you can see how much space we’re dealing with in comparison with the USB ports and the header socket.

Dockstar shielding

Some of the RF shielding will need to be removed, but thankfully the metal is pretty flimsy and easily cut.   Be sure that when you remove the little fins pictured that you do not distort the top of the metal shielding.  We need a surface as smooth as possible for the superglue to properly bind with the connector for the serial port.

Unneeded shielding removed

Here is the picture of the unneeded shielding removed.  Please only remove the shielding that you need.  Next, you will need to prep another three pin header just like you did for the cable.  Rather than trusting faulty measurements and guessing, we’re going to use the header’s pins themselves to point out where we need to place our holes.

Burned through holes

Using a pair of needlenose pliers and your soldering iron, heat the pins evenly and apply moderate pressure.  The pins may wiggle slightly but don’t let them move too far off otherwise your holes won’t be lined up. When all three pins have punched through, remove the pins with the needlenose pliers.  Use the small diameter drill bit to widen the holes and to furr out any residual plastic scraps.  Your finished holes should look something like below.

Completed holes

Just to make absolutely sure, go ahead and test with the connector and the cable to make sure everything fits properly.

Hole Alignment Test

If you’ve made it this far, you’re doing good.  Now it’s time to prep the connector for supergluing into the Dockstar’s case.  Since it’s a four pin connector and we’re only using three pins, make sure that the connector is properly oriented so that it fits properly and so that the serial cable can move freely in and out of the connector.  Back the cable off a bit so you can see which pin is missing and cut off the connector’s matching pin to eliminate a possible mis-wiring later on. Go ahead and attach and solder a wire to each of the three remaining pins.

Socket connection with wires

In order to glue the connector socket in, take the excess wire and coil it up for now. Apply a thin coat of superglue inside the Dockstar and when aligned, push the three pin header you used for burning the connector in through your drilled holes and into the connector.  This will hold the socket steady while the superglue cures.  Give it about 15 minutes to cure properly, then gently remove the pins from the socket.  At this point, you should have a fully mounted socket like in the picture below.

Glued in header socket

Now that the socket is taken care of, we need to attach it to the serial port on the Dockstar’s board.  Before we do anything permanent, we will test the serial port and then once we are satisfied that it’s all working, we’ll solder them in and close it up.   Start off with wrapping the ground wire to the lower right hand pin on the connection block.  This is the common GND connection and must be established first. If you are using my wiring plan, the GND wire is the single pin by itself on the three pin header we made earlier.

wirewrapped GND wire

The two pins to the left of the GND pin are the RX and TX pins respectively.  Attach the centermost pin to RX and the remaining pin to TX on the superglued connector.

Connected wires

Remember, we have NOT soldered the three wires yet.  Also, make sure that none of the wires are touching prior to connection.  In order to test the serial port and make sure we have it hooked up right, connect the three pin header on the serial cable to your socket on the back of the Dockstar and connect the USB connector to your computer. Do not apply power to the Dockstar yet.  Open up minicom and set the serial device to /dev/ttyUSB0, 115200, no parity, 8 bits, 1 stop bit.  When properly configured, apply power to the Dockstar and watch your console window.  If you got it right, you should get similar output like below.   If not, pull the power plug on the Dockstar and disconenct the serial cable out of the back of the dockstar.  Swap the left two pins (RX and TX) and try again.  You should get output like below.

Serial terminal output

Now that you’ve tested the wiring, disconnect the power and the serial cable from the Dockstar.  Solder the wires in place and reassemble the Dockstar. Be careful closing the cover as you want to make sure that the wires coming off the superglued socket do not touch the metal shielding. (Editor’s Note: I really need a hot glue gun)

Closeup of Dockstar prior to reassembly

Close it all up and test it one more time.  If everything works as should, you’re good to go.  Now you can access the serial port without having to take your Dockstar apart over and over again.

Completed mod with serial cable attached

Here is a picture of the completed serial cable mod. The serial cable is plugged in right above the keydrive in this photo.

View of Serial Port

Same view as above, but with the serial cable removed.  Nothing but three holes.

Image courtesy of Parallax.com

Hello Everyone!   If you’ve been in a Radio Shack sometime in the last year or so, you’ll know that Radio Shack and Parallax have teamed up to bring some variety to the parts drawers.  This once $50 serial RFID reader kit is now $10 at Radio shack although it only comes with two tags.  Read more for additional details about the Serial RFID reader now on sale!

The Parallax Serial RFID reader is 5 volt TTL compatible signalling and requires two I/O pins.  One is output for the “enable” pin which when brought low, turns on the RFID reader.  The tag data comes in on another pin to be read by your 5V TTL compatible microcontroller.   If you are using the 5V Basic Stamp or the 3.3V (5V tolerant) Propeller, then this is just a snap-in add on, no additional hardware is required.  Other controllers may require additional voltage converters to drop the TTL signal down to a voltage compatible for your controller.

Also take note that this is a 125kHz tag reader, so reading your company’s HID RFID tag will more than likely not work unless you have a 125kHz tag.

You can find the full datasheet, sample code and schematics from Parallax’s product web page here.

If two tags just aren’t going to cut it, you can take a look at all of Parallax’s tags here.

I know it’s been a while so here’s another post.  In this post, I’ll go over the hardware in this gun style barcode scanner that holds a real helium-neon laser tube with power supply! Although this post only covers the basic modding, there’s nothing to stop you from gutting the gun and using the HeNe tube for your own nefarious plan.

Before we get started, I can not stress the importance of safety especially with working with lasers and high voltage.  The laser energy generated in this gun is powerful and can result in eye damage, even if only temporary.  Unlike laser diodes that use an LED type technology to generate a laser beam, the HeNe tube is a lot more powerful and also generates UV radiation as well as laser light making it doubly dangerous.   Please be cautious when working with this device, and pay special attention to the aperture where the laser light is emitted.  YOURWARRANTYISVOID.COM CANNOT BE HELD LIABLE FOR THE USE OR MISUSE OF THIS INFORMATION. IT IS PROVIDED ONLY AS AN EDUCATIONAL REFERENCE AND SHOULD BE TREATED AS SUCH.

Now that the legal mess is out of the way….

After the last post with a barcode scanner was posted, I got to thinking about two laser “gun” style barcode scanners I have in storage.  I acquired them at a flea market about two years ago for $20 each but didn’t have enough information or internet access to be able to use them.  Well times have changed and so has the tools and information available to me so now I was able to complete what I had set out to do.

In this post, I will cover how to convert the Telxon LS-201 laser barcode scanner into a functional laser pistol using all of the included hardware.  We will cover the hardware that’s in the scanner, as well as the connections needed to fire the high voltage power supply for the HeNe laser tube.  Since the hardware is already pretty functional, most of our work will center around the control board and not the receiver board, but more on that later.

Getting Started

You will need the following tools:

• Philips screwdriver
• Razor cutter
• Soldering Iron
• 12VDC power supply (at least 750mA)

Teardown

We’ll start off with some pictures.

Aperture and receiver

This picture shows the aperture (top) and the receiver (front two windows).  When the laser is engaged, the laser is emitted from the aperture and is bounced off of a reflecting mirror (not shown) that produces a line which is then “read” by the receiver.  The laser dot’s position is controlled by the reflecting mirror using the receiver controller board and is then interpreted by the onboard logic to produce the codes to send.

Telxon LS-201

This side shows the holes that have the screws we will need to remove.

Opened up

After opening up the laser, you can make out the major components.  Reflector mirror and optics (upper right hand corner); Laser tube case (large black horizontal cylinder); laser HV power supply (copper box in handle); receiver board (top PCB); trigger board (lower PCB).

Receiver board

This is the receiver board (upper PCB0 and contains the “crab eyes” receivers that are used to see the laser as it scans the barcode. We won’t be using it so it will be removed.

trigger board

This is the trigger board.  All of our wiring will be done from this board.

optics

Here is the barcode scanner’s optics package.   The laser comes up through a lens in the back of the view, is bounced off of a stationary mirror in the red clip and then bounced off of the reflective mirror on the left hand side of the package.  You can see the servo’s cable that is used by the decoder board to generate the horizontal line. At this part of the build, wedge a piece of folded paper under the mirror to prevent it from moving.

top of optics package

This picture shows the lens and the mirror mentioned on the last picture. You can see the recess for the laser tube body and another mirror.  The indentations on the top and bottom of this view are used with large rubberized cushions to protect the laser assembly from drops, shock, etc.

laser tube

Here is the laser tube mounted in the bottom half of the protective mounts.  The emitter aperture for the laser tube is on the left, with a lens and a pair of mirrors.

laser tube detail

Here is a closeup of the detail on the laser tube.

laser tube detail 2

Another view of the laser tube with part number and the power rating.  This tube is a little bit more than 1 milliwatt.

Energized laser tube

In this view, the laser tube is energized and lasing.  The tube emits a pink/orange glow while energized.  The connection block on the lower left is ground which goes to the far side of the laser tube (right hand side in these photos).  The positive side of the laser tube is also the laser’s aperture.

reflector leakage

Helium Neon laser tubes consist of a fully reflective mirror and a partially reflective mirror.  The fully reflective mirror bounces the laser light back into the laser, while the partially reflective mirror is the laser aperture.  In this view, we can see that there is a bit of laser leakage from the fully reflective mirror which more than likely explains the low watt rating on the laser.

laser beam

This is the beam that is produced out of the laser’s aperture.

power supply wiring

The laser’s power supply has four wires coming out of it.  A white wire with yellow stripe (designated white/yellow), a white wire with black stripe (white/black), red and black. The large red wire is the High Voltage line for the laser tube while the thin black wire accompanying it is the ground wire.  In all testing from now on, the large red wire and thin black wire are not considered in any wiring diagrams as they are dedicated only to the laser power supply.

Let the Modding Begin

Before we begin hacking and slashing, let’s cover what needs to be done (in no particular order):

• We need to figure out how to apply power to the laser’s power supply.
• We need to figure out how to get the trigger to apply power to the power supply
• We need to modify the cable so that we can give the gun the proper voltage.
• We need to remove the now unneeded receiver board.
• We need to find a way to make an indicator LED so we know the laser is producing laser light.

Reviewing the Power Supply’s wiring:

Before we begin, let’s examine the power supply.  It had no identifying marks on it or manufacturer data on it so I really had to guess and get lucky.  Thankfully I was able to decipher it’s wiring method using the existing wiring on the trigger board and through some clever detective work.

As mentioned before, the power supply has five leads coming out of it.  After performing some testing and research, I was able to decode what the leads do and how to hook them up so that the tube is energized. Please remember that the thick red wire and the thin black wire that go to the HeNe Laser are not considered in this table.

RED wire:  This is the main power lead for the power supply.  This must be +12vDC.

BLACK wire: This is the ground lead for the power supply.

WHITE WIRE / YELLOW STRIPE: This is the “trigger” lead.  If it receives voltage between 5vDC and 12vDC, the laser tube will energize.

WHITE WIRE / BLACK STRIPE: This is an output lead and will be used for our LED indicator.

Test rig

Here is a pic of the test rig I used to figure out the wiring.  The rest of the components on that breadboard are not associated with this project.

Now that we have the the easy part figured out, it’s time to rework the trigger board. One thing of special note is that the trigger “button” is easily pried off.  I’m assuming that this was done on purpose as it would wear out quite quickly and an easy replacement method was needed.  Start off by cutting the ribbon cable from the trigger board and use a flat bladed mini screwdriver to gently pry off the trigger button

trigger board detail

Please note that we intend to reuse most of the components on the trigger board so be careful with your soldering iron.  With the trigger board separated from the  receiver board, start off by desoldering all the wires and resistors.

clean trigger board

While you remove all the parts from the trigger board, also make sure that the holes left behind are clear.  I used a pneumatic solder sucker to remove excess solder and debris.  This is the model I have, purchased from Radio Shack Rather than reinventing the wheel, we will be modifying the existing header and connecting only the pins we need to get power to the HVAC power supply for the laser and to light our LED. Due to the way that the trigger board is wired, we will be swapping the black header block from the laser power supply with that from the coil-cord cable. In the below picture, I have already removed the connector block from the end of the coil cord that goes into the gun and cut all but the black and white wires.

coil cord cable prepped

This image shows the cable with the black connector reinstalled. Remember, this is the laser’s black header connection. (Don’t worry, I’ll go over pinouts later)

power cable header connection

We then do the same thing with the laser’s HVAC power supply.

both headers ready

We then reattach the header pins to the trigger board and power it up. At this point, pushing the trigger button should fire the laser.   Next, we make the connection for our LED. In the below picture, the brown wire goes to the power supply ground, (black wire from the coil-cord) and the red wire (and the resistor) go to position 5 (from the right hand side of the trigger board).

Attaching the LED

Below is the diagram I used for wiring up both connector blocks:

connector block diagram

Now that all that is said and done, reassemble the laser, trigger board, HVAC power supply into the laser body and let’s test it again.  Depending on how accurate you were early on with the paper wedge and the servo mirror, it may take a couple of times to get the dot to point down the gun body.  Here is a pic with all the hardware installed and ready for the mating connector.  In this shot, you can see the LED that was wired in is working and that the laser tube is energized through a port in the housing an inch from my thumb:

Reinstalled hardware

So with all the parts back in the gun case, let’s test it. Below is my test shot.

Test Firing

So, where do we go from here?

Now that you know how to mod your laser scanner, the choice on what to do with it is completely up to your imagination.  Some ideas that come to mind:

• build a “target” to shoot at that toggles power to an appliance or light.
• build several targets to make a shooting gallery in your own home.
• Really cool presentation laser.  (Pens? Bah, I have a gun!)

This information is also useful in case you actually find need of a helium neon laser in any of your hacks and considering that this project had a $0 parts cost aside from the purchase of the scanner to begin with, makes a great price point for starting into experimentation with lasers.   Do the sensible thing if you do want to start experimenting with lasers. Please invest in quality eye protection and always practice safety first!

I hope you’ve had fun reading this article and I look forward to your comments. If you build something cool with your laser, please let me know about it!

FIRESTORM_v1

I have recently gotten my hands on a new Samsung Moment on the Sprint network. Within the next few days, I will post all the gory details from this Android n00b and will be offering a comparison against the other smartphone I have, the Palm Pre.

In this post, we’ll be going over the basics of using an old regular PC-gameport joystick with Parallax’s Basic Stamp powered Boe-Bot.  This howto will have all the information you need to get started including code, schematics and a parts list.  We will be covering how the joystick is wired and how to go about interfacing it with the Boe-Bot for an easy to use and easy to expand analog control method for your Boe-Bot.  Next step, world domination!

Foreword

The joystick is something that has been around quite a long time, even longer than computers.  The idea of being to control something on-screen by using a joystick is one that takes almost no learning curve,  is easy to start and you only end up getting better.  Even today in modern gaming, it is easy to find controllers with at least one analog joystick on it.  My Xbox 360 controllers feature two sticks per controller which give the gamer a very precise method for movement and aiming accuracy, something that buttons can’t quite provide.  As long as I’ve been working on computers, I always remember using PC analog joysticks in my games.

Nowadays, the modern PC joystick has all but gone the way of the dodo, however those few that are around now are USB and have a ton of buttons.  The legacy joystick (or “gameport” joystick) still has a bit of usefulness in it and today we will be covering how to get it to work with a Basic Stamp microcontroller.

Of course someone’s going to ask, “Why use a PC joystick?, Why not (insert control method here)?”.  My answers are:

1:  Cost – The PC joystick used in this tutorial was bought at a Goodwill for $3.

2: Ease of use – Once you have programmed your application, you just grab it and go. There’s no need to go over complex control methods or trying to remember what does what now.

3: Low Parts Count – In this tutorial, I used two capacitors and six resistors to get the joystick working.  Most other control schemes require a lot more parts.

Basic Theory of Operations

The way an analog PC joystick works is not very complex at all.  You have a stick which is capable of moving any position along two axes (X and Y) and with two switches or “buttons” for interaction.  The position of the stick is detected via two variable resistors usually around 10Kohm, one running horizontal (left/right) and one running vertical (towards you/away from you).  The computer would send a pulse out to the joystick and get return values from the variable resistors.  Using the returned pulse it could then decide on what action to take, how far/fast to move your character, etc..

The two buttons (or more) are detected through simple momentary contact switches. If the switch pin was high, then the button was depressed otherwise, the button was released.  These button switches are normally open and while the gameport pinout supports up to four buttons, additional buttons were made by figuring out how to multiplex them as shown in the chart below:

When using the PC gameport joystick, you would need to go through calibration which taught the computer the limits of your axes and the button layout.  Because variable resistors are not terribly accurate across manufacturers this calibration was a requirement as no two joysticks, not even those made by the same manufacturer,  would behave exactly alike. There would always be minute differences between the joystick’s behaviors so the calibration was a way to standardize the measurements and clean up the inaccuracy of the joystick.

In our tutorial, we will be using a two-button model.  This joystick is a very standard stick and has a trigger button and a thumb switch button.  It connects to the computer via a 15 pin D-sub connector usually to the sound card which has a Gameport connector on it.  This connector is usually orange on newer motherboards, if it exists at all.

On the bottom of this joystick, there are two sliders.  These two sliders can be used to “tune” the position of the VRs in order to be able to get the best range of motion for the stick.  You may need to use these during the next step for calibration.  Here is a picture of the bottom of my joystick.  The large circular things are suction cups which help keep the base down on the table while you move the joystick around:

After taking the bottom off, we can  see the setup of the two variable resistors (VRs).  Unlike most joysticks this one uses linear VRs and not the rotary VRs (sometimes called pots) that are commonly found for volume controls. We have oneVR on the left for the Y axis, and the other one along the bottom for the X axis, some support hardware and a small PCB:

The little circuit board at the top of the stick doesn’t conceal any electronics, It’s only a bypass as shown in these next two images:

This picture is of the bottom of the circuit board, As stated before, this only acts as a pass through to make wiring the joystick easier during production.

Here is a picture of one of the two linear variable resistors.  These are 100Kohm but yours might be different:

Now that the joystick has been opened up and we know all it’s secrets, it’s time to start on the interface for the BOE-BOT.

The interface circuit

The interface for your joystick is actually quite simple.  You will need the following items:

• A 15 pin female D-sub connector with ribbon cable – I used the one from an old PC that I had many years ago.  The long ribbon was perfect for this job.
• 4x 220ohm resistors
• 2x 10K resistors
• 2x .1uF capacitors – Note: I used ceramic capacitors in my project as they are easier to work with however in theory electrolytic capacitors should work as well. If you use electrolytics, please pay careful attention to the polarity as electrolytics can explode if hooked in backwards and may risk hurting you and/or damaging your microcontroller.
• Jumper wire as needed

This will provide the basic parts needed to perform our calibration test.  You will need to hook up the parts as shown in this schematic below.  Click on the image for a full size one if you need it.

Here is a full pinout of the PC gameport connector that shows all of the various things that the pins are used for: (Pinouts obtained from pinouts.ru – a good site to have handy)

In my D-Sub connector, pin 4 and pin 5 are shorted together however this may be done either at the joystick end or in your D-sub cable as well. When in doubt, test it with a multimeter.  If you find that during your calibration test, your buttons do not respond at all try examing those two pins to make sure that they are both shorted together.  WARNING! Although the pinouts.ru pinout provided above has some things labeled “Ground” and “+5VDC” use my schematic as the final verdict.   The reason for this is the pinouts.ru site describes the joystick’s gameport connector on a computer.  Since we are not using a computer and this is not a digital joystick, I have changed some of the meanings of the pins as shown in my schematic.  If you hook it up differently, you might damage your microcontroller.

Calibration Software

Now that the interface is built, we need to write the code needed for making the BOE-BOT “read” the joystick and to make it do stuff.  We will be using the RCTIME function of the Basic Stamp to charge and time the two .1uF capacitors.  By timing their discharge rates, we can then mathematically calculate the position of the joystick.

As far as the buttons go, they are just as easy as any other two buttons for your microcontroller.  The BOE-BOT will monitor pin2 and 3 and if they are brought high (by pushing a button) the BS2 will sense it and perform whatever action you have programmed.  For now, we are just getting the calibration information and to make sure everything works properly.  The tags for “Lights” and “Horn” will come in the next section.

You can download the source code called “BS2_joystick_diagnostics.bs2″ from my downloads page, or here is the direct link You might need to right click on the link and go to “Save As”.

After loading it into your BOE-BOT, be sure to leave a debug window open, as this is where you can see the RCTIME counts and the buttons.  You may  notice that the values will be all over the place and will constantly be changing but this is normal.  Play around with it a bit and get a general feel for how your joystick works.

If for some reason, your RCTIME is stuck at 0, this indicates that the Basic Stamp is not seeing the capacitor or is not sensing the capacitor’s discharge.  You will need to check your wiring to make sure everything’s lined up. If need be, you can use a 100Kohm resistor between pins 1 and 3 or between pins 1 and 6  on your 15 pin D-sub connector to test.  If RCTIME shows up there, then use the multimeter on your joystick’s D-sub cable and make sure that you can see the resistance changing on those two sets of pins.  If you get no connection on the joystick, you could have a bad joystick on your hands.

Here are the images of my RCTIME output along with a picture showing the position of my joystick.  You will have different numbers, but the format is still the same.

Center or "zero" position

X (horizontal) axis left

X (horizontal) axis right

Y (vertical) axis up

Y (vertical) axis down

Button 0 pressed

Button 1 pressed

Once you have a “feel” for how the joystick responds, let’s actually do something with this. You will need to figure out the zones on where to apply the speed settings.   The BS2_Rover application contains routines that can filter out and adjust pulses sent to the servos however this requires a bit of calibration (hence the calibration application).  All you need to do is to figure out where your joystick should switch between off and low, low and medium and lastly medium and high.    The reason for this is that for precise movements, we don’t want the BOE-BOT to lurch out of control, and while high speed all the time might not be a bad idea, it can be cumbersome trying to get into a small space with it.

Getting it to work

Go ahead and download the file “BS2_joystick_rover.bs2″ from my Downloads page or via this direct link. Load it up in your Basic Stamp Editor  as now we need to make some adjustments to it.  I’m pretty sure that your joystick will behave differently than mine will which is why my code won’t work out of the box.  Well let me rephrase that, the CODE will work, but the joystick calibration will be off.   Using the calibration application above, you can get the RCTIME values needed to make the servo speeds and the directions work properly.  Look at my speed chart below and you will get a better understanding how the BS2 rover works:

With this chart you can see at which points the BOE-BOT will change speeds.  You will need to make a similar chart for your joystick using the calibration program and then you can edit the BS2 Rover file and add those settings in the two GOSUB statements.  The DEADZONE is important as this is the point where your stick’s RCTIMEs will fall when no one is touching the joystick.  It is important to have a deadzone that matches your joystick to prevent your BOE-BOT from running away from you.

Something of note is that my chart starts at “1″ and not “0″.  This is because if the VR is at minimum resistance RCTIME will still return a “1″.   The only time RCTIME will return a 0 is if there is no load for the capacitor to discharge to, for instance when the joystick is disconnected.  In the event that RCTIME does return a 0, then we will send out the same pulses as what we send out in our deadzone so that way our BOE-BOT does not move once the joystick is unplugged.

Here’s how the two subroutines work in a nutshell.  You start off with a pulse value of 200 and depending on where your RCTIME is, you will either add to it which makes the servo rotates one direction at one of three speeds or you will subtract from it which will make the servo rotate the other direction at one of three speeds.  Once the comparisons are done,  you add a constant value of 550 to the pulse value.  This pulse value will then get pulsed out to the servos and the wheel turns.

The reason 550 was selected was because 550+200 = 750 which is the point at which your servos do nothing. In the speed chart below, we can see how the offset affects the servo pulses and how each of the two items correspond with the speed levels:

So now that you understand the two subroutines, go ahead and edit them to match your joystick’s behavior and desired positions.

Extra fun stuff

Now that we have the complex part out of the way, we can also instruct the BOE-BOT to do something when we press the buttons on the joystick.  I have added a buzzer, a 220 ohm resistor and an LED to the last schematic so that now when we press the trigger button, the piezo buzzer will make a beep-beep sound and when you hit the thumb button, you will see the LED turn on and off.   Here is the updated schematic with our new parts. (Click on it for a full size image)

Once you have made the needed changes to your code, there’s one last thing that needs to be done before you upload it to your BOE-BOT.  Check one last time and make sure everything is set properly, otherwise you might have unexpected results.  If all looks well, go ahead and upload then try it out.

Here is a video I made of my BOE-BOT in action.  For this test, I used a white ultrabright LED which produced a lot more light than the standard LEDs that came with the BOE-BOT.

The “chugging” motion is normal.  This is the BOE-BOT, checking the RCTIME of X, pulsing out the X servo, checking RCTIME of Y, pulsing out the Y servo, checking the buttons then repeating itself.  Since the BOE-BOT is a single-process chip, it can only do one thing at a time otherwise the motion would be a lot smoother than it is.   If you are using the Propeller, you will get smoother action out of it by dedicating a COG to monitoring the joystick’s X and Y axes, and another COG to controlling the servos.

Last words

Using an analog joystick for your robotics projects can be an excellent way to bring an easy and intuitive interface for robot control into your project and I hope that this article shows you how easy it is to use.  It doesn’t take any fancy coding, expensive hardware or overkill designs, just some basic knowledge of how RCTIME works and a few bucks for the joystick. With a minimal part count, you can increase the flexibility of your robot’s design quite easily and you might even save yourself some programming headaches later on.

As always, thank you for reading.

FIRESTORM_v1

In the first post for the new “Hardware PrOn” category, we will be dissecting a common point-of-sale barcode scanner.  This particular victim is the MS700 laser scanner manufactured by Metrologic (now owned by either Honeywell or Gilbarco) which reveals a very nice discovery inside.  So, grab your screwdrivers and let’s take a look.

I got this particular discovery from EPO (see “Places to get stuff”) and since it was untagged and in their “Bargain Corner”,  I was able to get it for the awesome price of $2.   I figured that for that price if I didn’t score something awesome, then at least I’m only out  the $2 dollars.  Since this was a laser based scanner, I figured I could get another laser diode and maybe the beam splitter mirrors for working on my line generator project.

First off, we’ll start off with some pictures. Here is the gallery of photos taken during the disassembly.  You can click on any of them to get a brief description. Clicking on the image again will give you a much larger image.

As indicated in the gallery images for the laser diode mount, don’t remove the focus lens.  I doubt I’ll ever get mine put back to a working order.

Additional Research

If you want to see if yours works first, you will still need to take it apart.  On the power supply PCB, there is a brown connector with three pins.  The center pin is ground and the bottom (towards the metal box side of the PCB) will be the positive voltage side.  This device ran comfortably on 12 volts DC but can go as high as 30VDC if need be.

According to some research, this is an RS-232 barcode scanner however I have not been able to figure out the pinout of the 15 pin header in order to hook it up.  If you are able to get this information, please let me know in the comments section of this post.

As indicated in the gallery images for the laser diode mount, don’t remove the focus lens.  I doubt I’ll ever get mine put back to a working order.

What you can do with it

I’m sure that there are a lot of things that one could do with an optics setup like this.  Not knowing the optical characteristics of the optical receiver I’d hazard to say that this would be a good base for object detection and avoidance on a robot. You could read the position of the mirror cube using the pulses of the yellow wire and then some math could determine where the object is in relation to the robot.  Failing that, you could always make a line generator for some really nice rock-concert effects.  If you take this approach, I recommend going with a green laser, but you’re probably going to need a heavy duty laser or one that can withstand being on for extended periods.  Most laser diodes in laser pointers are not rated for this kind of work so choose wisely.

Well here’s the seccond post as promised.  These posts should also proves that you don’t have to know sick computer skills or mad hardware to be able to pull off some bad ass hacks. In this post, we will address the Nerf Nitefinder and it’s so-called light sight.  While the verbage does get around the expected/anticipated lack of a good lasersight, this post will walk you through adding a real laser sight to your Nitefinder.  Read on for more details along with lots of pictures.

Foreword:

During Xmas/Yule/whatever, I was given the lovely gift of a Nerf Nitefinder handgun with a touted light sight. Upon final inspection however I was dismayed as was the person that bought it that the device did not contain a real laser sight as evidenced by all the commercials on TV. Not to be let down by a mere exaggeration on Nerf’s part, I set out to create a lasersight for this not so lasersighted weapon of nerf destruction.

While I was researching this topic, I came across many many websites about Nerf modding, but everyone’s solution seemed to be more of writing off the nerf sight and duct taping a keychain laser pen to it. If I was going to do something, I was going to do it right damnit, and Duct tape wasn’t going to be the solution. After a few Nerf wars, I also had become weary of having to recalibrate the optics because a frenzied firefight resulted in a slight bump to one of the pieces of plastic that jutted from the sides of the optics package at the end of the gun.

So here it is, the fruits of my hard labor, and my beer, the instructions necessary to install a lasersight in the Nerf Nitefinder.

Required Tools and Parts:

• Nerf Nitefinder
• Some common 2 battery laser pen
• Note: The 2 battery part is CRUCIAL, a 3 battery pointer won’t work as well.
• A sacrifical NERF dart.
• A soldering iron with solder
• Small tip Philips screwdriver (+)
• Knife

Total Cost: ~$20.00, depending on cost of laser pointer.

Note: The reason why a 2 battery laser is important is because the Nitefinder itself only has two batteries, equalling about 3.0vDC. Most laser pens take 3 or more batteries which is 4.5vDC or more (each cell is typically 1.5v). Since I didn’t feel like carving out a battery holder, the 2 battery laser just made sense.

Pre-Analysis:

For those of you considering, this is what the light sight looked like before the hack was completed.

This image was taken with all the lights in the room off, the gun about 2 feet away from the wall and the camera set to nite mode. The camera didn’t capture the “halo effect” that made the dot rather distracting. The dot wasn’t really a dot either, it was more of a funky “U” shape, which is explained later. There’s definately room for improvement here.

Phase 1: Prep the gun.

Start off by removing all the screws, the battery cover and the batteries from the gun. It will look something like this:
Of particular note is the circuit board attached to the red and black leads. This is the source of the “light”. The picture below shows us that it is nothing special, just a high intensity red LED and a resistor.

Go ahead and unscrew the two black screws holding the black tube down. This is where we will be doing most of our work.

The entire sight module comes out. It consists of the aforementioned light board, the black tube and the housing that protects the optics package. Remove the light board from the end of the black tube.

This picture shows one of the two screws necessary for attaching the optics package to the sight. Remove both screws and carefully use your knife to scrape away the glue holding the two parts together. Set aside the tube, optics package and the gun for now.

Phase 2: Rip the pointer apart.

A special note: Not all laser pointers are created equal. Some modules like this one were press-formed together, while others might have a retaining nut or some other screw-in device. It is especially important to pay attention to detail as there is a piece on most laser diodes that you do not want to unscrew and that’s the focusing element of the laser itself. This particular pointer was press-formed together, which made it an easy harvest. I would avoid using the lasers that multiple tips, as this is an almost sure fire screw-on situation that might just leave you screwed in a bad way.

Start by removing the batteries, Take special note of which end is positive, typically it’s the end that you unscrew to get to the batteries. Polarity matters later on.

With the knife, locate the seam between the head of the laser pointer and the body. and press hard to start seperating the two pieces.

After you get it scored enough, or if you feel the head loosening, gently pry up using the knife blade or a screwdriver. You will end up with something like this.

The brass cylinder is the actual laser diode we came for. This particular model is press-formed together and is held together by a star shaped collar. This collar was easily moved by a very fine screwdriver.

Before you attempt to extract the laser, look inside the tube and see what you might need to do about getting that switch out of the way. This laser had a rubberized switch so I didn’t have an issue but you might. If necessary you can destroy the switch as we will not use it, but MAKE SURE IT’S THE SWITCH AND NOT A CAPACITOR. In the picture below, the switch is the little white boxin the lower right hand quadrant. The other white pieces are parts of a plastic sabot made to hold the board in place.

After successful extraction, you will have something like this.

Now that we have the circuit out, it’s time to find out where we’re going to solder. Remember earlier when I said pay attention to the batteries? This is why: In most device, the chassis is ground and the switched power is hot or positive. If the batteries plus sides were all pointed to the spring, then the pointer has a cold chassis, meaning that it is always connected to negative. If the batteries plus sides were all facing the unscrew cap for the battery compartment, then it has a hot chassis. This is one of those your mileage may vary things. Mine had a hot chassis, which means that the switch was controlling the negative or ground side of the batteries. An examination of my circuit board showed me the pads for the ground quite easily. Remember, that the white box is a switch and we will remove it soon.

This is the critical part. Since my laser pointer is hot chassis, that means that the circuit is getting its power from another contact. The only contact that is evident is the brass casing of the laser diode itself! Since this laser diode has three contacts, it is extremely important to locate the contact that does not have a ring around it and that you can see solid metal all around. This is the casing lead and where we will be attaching our positive lead. Alternatively, if you see a lead labled Vdd like this circuit board does, that is the location of the positive connection. Vdd=power, GND=negative or ground.

Now it’s time to fire up that soldering iron. Detach the red and black leads from the light board on the gun, set aside the circuit board. On the laser pointer, remove the switch and the spring end.

Looking at the solder traces (the bright green lines) you can tell where the switch was. You will want to attach the black lead to the pad that does not go to the spring. This bypasses the switch and leaves it always on. (Remember: the trigger switch will control the power to the laser.)

If you still have the shroud and the star shaped retainer, remove them now. They are not needed and can be discarded. After soldering, it is a good idea to check that the diode still works and that we haven’t shorted something. Carefully connect the two AA batteries and press the trigger button. The Laser should light.

Now that’s all said and done, we have a functioning laser diode, now it’s time to mount it in the tube. Grab your sacrifical nerf dart and set it alongside the black tube with the laser diode circut. You will want at least a 1/2 inch.

Cut the dart enough so that there is no foam over the end of the brass laser diode and so that there is enough foam to cover the circuit board.

Next, slit the cut piece lengthwise and place the laser assembly inside.

Grab the optics package and set it on the table, screws side up.

Remove all three screws, and open up the optics package.

Remove the lens, and the two orange clips. Discard these, we don’t need them and they distort the laser light. Reassemble the optics package and go to the next section.

Phase 3: Reassembling the sight

This is going to be almost as challenging as getting the laser diode out. You will need to take the foam wrapped laser assembly and squeeze, shove and stick it in the small end of the tube. Make especially sure that there the foam stays covering the brass diode and that you don’t destroy the circuit board. The end result will be something like this.

Looking down the tube, we will see the laser diode still there with nothing protruding over the little hole in the brass. This is actually the laser’s aperture and any blockage will cause the dot that the laser projects to look weird.

Reattach the optics package to the barrel and screw the barrel to the gun. You may need to trim the foam in order to get the gun halves to get back together.

Phase 4: Now, about the firing distance

The following image is an exploded view of the assembly at the top of the gun. This is held in place by two screws and is easily removed. The parts in order from left to right are:pressure chamber, spring, regulator, stabilizer tip, barrel. For max effectiveness, remove the spring and the regulator. (items 2,3)

Reassemble the barrel like shown and reattach to the gun. Make sure that all springs are in their proper place, less the regulator spring.

Phase 5: Calibration

Now that both mods are in their final stages of being complete, you need to calibrate the gun. Put the other half of the gun on, but do not use any screws just yet. This will be a process of fire and adjust over and over again until you are satisfied. There are no pictures for this phase, just remember that if your gun shoots to the right of the laser dot,wiggle the laser to the left. If it shoots low, wiggle it down. After a few shots, you’ll have it zeroed in and working fairly well.

The reason why I didn’t calibrate right after we put the sight back on was because of the firing distance mod. If you had calibrated and then performed the mod, the calibration would be no good because of the considerable difference between the air pressure hitting the bullet pre and post calibration.

Phase 6: Give the cats a new reason to hate you.

If all is well, the gun is sighted in and working, go ahead and close it up! You’re done.

See, now that’s a real lasersight!  Happy Nerfing!!

FIRESTORM_v1

Well, I will admit that I’ve been slacking a lot.  There are posts that need to be posted, and I’ve been extremely busy at work.  So, to make up for it, today’s going to be a two-post day!.    In this post, I’ll demonstrate how to modify the Nerf Maverick chamber to work properly like a real revolver.  Read on for a complete step-by-step guide to this basic Nerf mod.

Foreword:

I recently got my hands on the new Maverick which is Nerf’s response to the demand for a revolver-type handgun for nerf fanatics. The drawback is while they could have gone all the way with their design they did not pay enough attention to one critical issue: loading time. The Nerf Maverick is a pain to load because you have to pop out the chambers as with a standard revolver but  the Maverick’s chambers only come out about an inch, giving you visibility to put in about 2 darts without needing to rotate the chamber.   My hack will give you visibility to 4 of the 6 chambers in the gun.

This gun shoots remarkably well given the really short pneumatic piston in comparison to the other guns I have.  This leads me to wonder why the other ones suck as far as range is concerned, but that will have to wait for another day and another hack.

Required Tools and Parts:

Total Cost: ~$8.99 (there are no parts required.)

Pre-Analysis

The Nerf Maverick’s chambers only come about an inch as shown below. I think we could do better.

Disassembly

The disassembly starts off with removal of the grey slide at the top of the gun. Lay the gun on the table with the chambers pointing to the right, remove the three screws and gently remove the half of the slide facing you. Set it aside.

Now you are safe to remove the rest of the screws. When I came across this step, I had to use the knife to gently seperate the two halves. You will want to keep that other half of the slide against the other half of the plastic frame as there is a small spring that is connected to the silver pin that makes up the slide. This is not the end of the world if you manage to seperate it, but you will need to use the paper clip to re-string it if it flies off. Thankfully the other end is attached to the frame by a screw.

Now that you have the gun opened, you will need to carefully remove the chambers. This can be done, but it will take a bit of finesse. Below is the front of the chamber assembly.

This is the back of the revolver. The hexagonal shape matches with the orange hexagon advancer in the body of the gun.

This is the mating orange advancer and the pneumatic piston for firing the darts.

This picture shows the chamber in the gun, with the chamber in place for firing. By messing around with it a bit, we can see the plastic that needs to be removed.

With the chamber seperated, take the red sharpie and highlight the rounded plastic edge to remove.

Take the sharpie and highlight the little square next to the advancer and the piston.

Take your knife and remove the two pieces of plastic. Be warned that the plastic is tough, so don’t cut yourself. You want to get it as smooth as possible so that way it doesn’t foul up the chamber’s movements. This is a shot of the chamber with the plastic removed.

And another shot of the plastic removed next to the advancer.

Reassemble the gun, and revel in the fact that your Nerf revolver now works closer to a real revolver!

Conclusion

While I’m not quite sure why Nerf didn’t implement this in their original design, it wasn’t exactly rocket surgery to make it happen.  I think that this makes the Maverick this much more useful as when you’re in a firefight with the rest of the members of the household, the last thing you have time to do is reload.

Happy Nerfing, everyone!

FIRESTORM_v1

BIG MONSTEROUS LEGAL DISCLAIMER: This information is provided as anecdotal as-is information. It is recommended when working with electronic components to replace the defective component with a component of the same type, model and rating.  Battery backups are no exception to this rule and as such we recommend that you follow the exact ratings as specified on your UPS, even if they differ from the information on this site.  When in doubt, go with a 1-to-1 replacement, or better yet, purchase a replacement battery pack from APC directly.  By following the steps in this guide, you indicate that you can not sue firestorm_v1 or those of us at YourWarrantyIsVoid.Com if you burn your eyebrows off or cause damage to loved ones or property, etc..

Now that the legalese is done with, let’s talk about this a bit.

Foreward:

Ever since the dawn of time, or at least the dawn of the computer age, mankind has been faced with one monsterous problem:  How to keep the computer running when the power goes out.  Even in the 21st century, we are still not immune to the power failures, surges and brownout/blackouts that plague our planet’s power grid.  The solution was to use uninterruptable power supplies (UPSes) also commonly called “battery backups” to keep the juice flowing, even though the power from the electric company had ceased.  The idea was that power would be stored in batteries and would be used through specialized circuitry to recreate the line voltage that our beloved machines needed to operate.  The idea was a grand saviour to the information age  and since then have saved countless months of uptime loss, unavailability and other such lack of availability.

However, with every great solution is a thorn in its side.  In our case with the batttery backups, the thorn is the batteries.  Every now and then, through regular use and standby charging, it becomes necessary to change them out.  Usually this cost is a lot less than just buying another battery backup and is a preferred method to keeping old but still usable UPSes out of the trash can. In my specific case, I have an APC Battery Back-UPS XS 1500 and it has served me extremely well through the years.  Unfortunately an extended power failure had knocked it and the addon battery pack, BR24BP out of comission and had rendered the UPS useless.

Initial examination:

Pior to just ripping the face place off of anything, even if it pisses me off, I perform a good bit of research using Google and Yahoo to attempt to find disassembly instructions for something.  In the case of the battery backup’s battery pack, I had nothing but a bunch of forum posts with people looking for the same details.  Unfortunately no solution was to be had so I started investigating on my own and was ultimately successful.  This writeup is a testament to those findings and a howto for anyone that was as lost as I was with trying to find a way in.

BR24BP side vew

This is a shot of the BR24BP in all it’s glory.  Despite it’s innocent looking exterior, it’s a mofo to get into.  With no visible way of getting in, I set out with my metal screwdrivers and started prying like a madman.  Eventually, I was able to get the white front cover off and the secret to this beast was unlocked.

Front cover finally off

(The grey piece on the back was held together much in the same fashion, pardon editor’s fault for the back showing ajar. )  In this shot, we learn something important.  The front is not held on by any fancy method, locking mechanism or other trickery.  It is held to the front of the battery backup by means of a pair of snaps.  One at the top of the cover pointing down, and one at the bottom cover pointing up.  It would be almost trivial to modify the case so that you could get into the battery box at some point again to do a second swap out fo the batteries.

Back of front cover

Here is a shot of the front cover.  The back cover is identical to this except it is grey and has a hole for the power cable to go through.  It could be theorized that the ends of the snaps are sliced to prevent from someone gaining access to the innards of the battery box.  It could also be theorized that a quick session with a Dremel could prodice a hole with which to pry up on the snaps to gain access in the future without having to pry the case open like your life depended on it.

Back cover pried off

This is a shot of the rear cover after being pried off.  The thin holes at the top and the bottom are the holes for the snaps.  Once finally freed of both the front and the rear faceplates, we are left with the battery box and six phillips screws from victory.

battery pack sans front/back covers

In this shot, we can finally remove the only screws in this battery pack’s setup and pull off the cover to reveal the batteries inside.  One special note about the covers.  They are omni-directional (Editor’s note: omni-sidal seemed to not be a word. ) meaning that the “left” side could easily be the “right side”.  The only thing that determined direction was that the indentation for the pedestal foot was at the bottom (pointed towards you if on a table) and that the cord came out of the “back”.  Aside from that, it was anyone’s game.

Finally unboxed

(I apologize for the blurriness of the full-size picture, just use the thumbnail for general positioning data.)  Behold, here is the batteries in all its glory.  Keep in mind that my top two batteries are “poofy” and need to be replaced.  The bottom ones, are not poofy so will get taken to a battery place to get charged and tested.

Battery type and model #

Before we get into wiring diagrams and all that nonsense, please make sure you use the right battery.  These are 12 volt,  3.4A batteries.  CSB# HR-1234W-F2 and are the Sealed Lead Acid (SLA) type.  IT IS CRITICALLY IMPORTANT THAT YOU USE THE SAME TYPE AND RATINGS OF BATTERIES IN YOUR UPS.  EXTENDING YOUR UPS MAY GIVE YOU ADDITIONAL UPTIME BUT WILL CAUSE YOUR ADDITIONAL UPTIME TO FAIL AS THE CHARGER CIRCUIT CAN NOT HANDLE THE EXTENDED CAPACITY! (Can I say this enough?) If you are in doubt about whether or not you have the right battery, take one from the pack to an Interstate Batteries or a Batteries Plus and get four just like it.  Bring them home and wire up as covered below.

Wiring it all up:

The interesting thing about this pack is that despite the link that I found for APC, this is actually a 24VDC system, not a 12VDC system as advertised. Granted, the batteries themselves are 12VDC, but they are hooked into a 12x2x2 array meaning that the batteries are connected in series (to make 24VDC) and then are connected in parallel to another pair connected in series.  The entire thing ends up being a 2x 24v array as shown in our next picture:

Battery Hookup

Ok, so let’s review this hookup.  The umbilical cord that goes to the main BackUPS is in my hand.  For now, ignore the little yellow wire.  It has nothing to do with our hookup at the moment.  Clockwise from top left, we have the UL (upper left) battery, UR (Upper Right) battery, LR (Lower Right) and LL (Lower Left) batteries.  The umbilical has two positives and two negative leads on it. WHEN HOOKING UP BATTERIES, YOU MUST OBEY THIS IMPORTANT RULE: AT NO TIME WILL THE POSITIVE AND NEGATIVE OF THE UMBILICAL BE ON THE SAME BATTERY!!! THIS WILL CAUSE AN EXPLOSION AS THE 24V BATTERIES TRY TO (AND SUCCEED) OVER CHARGE THE SINGLE 12V BATTERY! That being said, connect one of the RED wires to the positive terminal on two batteries and connect the BLACK wires to the other two batteries’ negative terminals.  At this point, all four batteries should be connected with one connection from the umbilical.  Connect the BLUE wires from the positive battery’s NEGATIVE terminal to the negative battery’s POSITIVE terminal.   In essence, you have created two 24 volt battery packs made of UL and UR, and LL and LR respectively.

Little Yellow Wire

Now, back to this little yellow wire (and the 80A fuze)  This wire acts as a “Sense” for the battery backup to determine the battery pack’s overall health. The wire has a resistor shrinkwrapped inline with it and should not be tampered with.  Doing so may adversely affect the UPS’s operation.

Afterthoughts:

It’s been fun dissecting this battery pack however it was hard as hell initially.  APC does not make it easy to pry open the front/back of their UPS battery packs.  I’m hoping that someone aside from myself finds this information useful as it was not easy obtaining it.  If you have any information on where to get good replacement batteries, or you wish to share your experience, feel free to fire back at me in the comments section.

Until the next post, happy hacking!

FIRESTORM_v1

UPDATE!!! 11/10/09

Reader “Steevo” wrote in to catch me on a critical error in regards to this resistor.  M initial calculations were incorrect, the value of this resistor is not 20K ohm, but rather 20 ohm, Please make sure you use the correct resistor if you ever need to replace it.

The secret is revealed!

UPDATE: More details about the power connector from the BBU power pack to the UPS

After requests for information in regards to the power pack’s connector, I realized that I had made a serious oversight.  I had not documented the power connector that connects the battery pack to the UPS body.  With this in mind, I took some more pictures of the connector:

Power connector

The power connector has four pins holding the strain relief on.  After getting the pieces pried apart, the end connector slides off and you can then see the wiring on the inside.  Barring that, I went ahead and was able to extract the outside case off of the three spade connectors as shown here. In order to extract the three spade connectors, you will need to take a long sharp screwdriver and pry the plastic clips holding the spade connectors down.

connector endcap

Here’s the connector with the spades having been successfully extracted:

successful extraction

Keep in mind that the plug orientation is not certain as I’ve reinstalled the UPS and it’s buried under the desk.  The red mark on the connector jacket is there for orientation purposes, but interfacing with the UPS may require that the black wire is on the left, and the yellow wire is on the right.

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