How To – Turn an LED Scrolling Badge into a Desktop LED Sign

17 Apr 2010
Author: Joel The Great  |  Category: How To..  |  Comments (2)  |  Add Comment

Many years ago I bought an LED Scrolling Badge from for a few bucks, and shortly after I got it I hacked it.  Being the lazy sod I am I am just now getting to writing up a how to.

First, general crap: This could void warranties, break things, hurt yourself, etc etc.  So don’t be  a moron.

Back story: Basically I wanted to use the LED Scrolling badge as a sign on my desk, seeing as the cool, multi color, multi function LED signs are usually in the $100 and up range.  Well I tried it out and it was on my cubicle wall for about a week and the battery died.  So I took out the battery and looked at it.  I noticed it was one of those flat CMOS/Watch type batteries that is thin and about the size of a quarter.  They aren’t cheap to replace, and it was obvious buying 1 every week would be retarded.

That’s when I had a great thought.  The battery was labeled 3V (V for volts).  I remembered that a standard cylinder type battery (AA, AAA, C, D) are rated 1.5V, so two of them would = 3V. I pondered what battery to use, and used my vague knowledge of things to remember that the only real difference between the different cylinder type batteries is how much juice (electricity) they contain.  So if a small watch battery would last about a week, how long would two D batteries last?

So I set out, got the materials listed below, and did basically what I’m about to tell you. I also figured out two different ways to accomplish this. One method that requires soldering, one that does not.  I’ll start with the soldering method first as it is more stable, and geekier.

What you will need:

  • LED Scrolling Badge
    • Can be found at various online retailers, you need to get one powered by a 3v watch battery.
    • If you get an Badge that uses a different amount of Voltage you will have to figure it out yourself (You can leave a comment and I will attempt to help you out).

      LED Scrolling Badge

      LED Scrolling Badge

  • Battery Holder with wires. D-Cell size (you can go with AA, or AAA if you want, but I used D).
    • Can be found at Radio Shack/Online

      Battery Holder

      Battery Holder

  • Tools (Screw driver, soldering gun, knife, whatever else you think you need)
    • This is crap you should have anyways if you are any sort of human.

      Knife, Screwdriver, Solder Gun

      Knife, Screwdriver, Solder Gun

  • Optional: Washers (preferably the same diameter as the coin shaped battery), Paper/Card Stock/Cardboard, poster putty. (I will tell you how to make a solder-less version at the end)
  • 10 minutes (give or take)

Step 1 – Battery removal

Locate the battery compartment on your LED Badge.  On my model it was located on the bottom and slid out like as a tray that held the battery in place (I have no picture of this as I removed and threw away the battery tray, and battery when I originally modified mine).  Remove the battery and note it’s orientation (as in which direction is the positive part of the battery facing, and the negative. Also make sure that it is 3 volts. No more, no less.  If it is different then 3V, you will have to modify what you do to get this to work.

Step 2 – Take it apart

Use your screwdriver, or whatever tool is necessary to open up your LED Badge.  Mine had six mini screws on the back holding it together. DO NOT LOSE THE SCREWS! They are tiny, and your friends will make horrible jokes about you having a screw loose.

Opened LED Badge

Opened LED Badge

Step 3 – Locate the power source

On the circuit board should be the place the battery went.  It should have something that is marked as +, and one marked as – (positive and negative).  This can be figured out easily if you remember which way the battery went into the battery area.  As you can see on mine, it had this metal tab sticking up that was the negative lead, and four little solder type pads that were the positive leads. Yours may differ.

LED Badge Power

LED Badge Power (Sorry for low image quality)

Step 3.5 – Test

At this point you can temporarily place the batteries in the battery holder and hold the ends of the wires on the appropriate locations to make sure the LED Badge lights up successfully.

Step 4 – Strip and Solder

Strip the ends of the wires on your battery holder if they aren’t already. (Make sure you take the batteries out so you don’t do something stupid) For me I soldered the red (negative) wire to the metal tab that was marked as the negative lead to the circuit board.  And the black (positive) wire to one of the 4 positive solder pads directly on the circuit baord. (note: I realized that all 4 pads worked as a positive lead and it only had to be soldered to one).  Super Ultra Extra Note: The LED Badge you purchase may have different power points, this will take thinking on your part.  If you need help locating them, take a good picture of your board and I can possibly help.

Step 5 – Test and Re-assemble

Now that you have it all wired together, put the batteries into the holder to make sure it all works.  Then all you have to do is re-assemble the badge and Viola! LED Badge powered by two D-Cell batteries.

LED Badge Working

LED Badge Working

For those of you who either don’t own a soldering gun of any sort, or want to be able to use it as an LED Badge every now and then, I have a solderless method.

Here is a quick how-to:

  1. Strip back a good amount of wire from the D-Cell Battery holder.
  2. Wrap the exposed wire from the black wire around one metal washer, do the same for the red wire. (You can also solder the wires to the washers if desired)
  3. Cut a piece of cardstock/paper/cardboard to a size just a hair bigger than the washers
  4. Place the cut piece of paper between the two washers kind of like an Oreo with the washers as the cookies and the paper as the creme filling.
  5. Slide the washer/paper assembly into the battery slot making sure the washers are going in with the correct orientation (black wire washer going in toward the positive side, red wired washer going toward the negative side of the battery compartment)

That method is not completely stable and secure, but it will work.  When you want to use it as a badge, just pull the washer cookie out and put your watch battery back in and off you go.

End Results and Battery life:

My LED Badge came with one of those magnetic backings.  I used some poster putty stuff to stick it to the battery holder and set my LED Badge on it.  The battery holder works as a stand and can be easily put anywhere on your desk.

LED Badge Assembled

LED Badge Assembled

Sorry for the camera quality, I was using my Cell Phone.

As for battery life.  How does 8 months sound?  That’s right, this can last anywhere from 6-8 months depending on some factors.  I left mine on, CONSTANTLY, on the lowest brightness setting for over 6 months. Toward the end of the six months I had to up the brightness as the batteries got weaker.  So instead of needing to buy a new $2 watch battery every week, I only have to buy two D-Cell batteries (about $2) once every 8 months.

Now if you turn it off when you are not at your desk, like on weekends, holidays, at night, I bet you could run this for over a year on one set of batteries.

Thanks for reading, if you have questions or comments please leave them below and I will do my best to answer them.

2 Responses to “How To – Turn an LED Scrolling Badge into a Desktop LED Sign”

  1. How To – Turn an LED Scrolling Badge into a Desktop LED Sign … | LED Tools Says:

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  2. N Tesla Says:

    Reminds me you could, for a few bux and next to zero time, get the same thing from allelectrics. com or Edmund Scientific or Ramsey Electronics. See also “x spy gadgets for the the evil genius” book. Way cool.
    BTW do you have any quick (read that non-techno-geek) plans for a cell phone fooler, so no one with in x meters around me can use their damn cell phones. Morons.