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

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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