Minimalist IR Pen: No Soldering, Under a Minute, Under a Dollar.




My first instructable, hope it is useful:

If you want to test out the J.C. Lee (the J.C. stands for Johnny Chung, but he does kinda does miracles too...) or the Smoothboard program at (light years ahead, because Boon Jin started where JCL ended, thanks tthe open source programming...) well... YOU NEED an ir pen.

I do theatre in English, and Magic/circus for ESL. and you can see my page (only the blog is in English the rest is in Spanish.) here. I work with a lot of teachers that know a lot about teaching and nothing about a soldering iron. So I came up with this..)

So, for non-techies or impatient people here is a tiny pen with just one LED, a 1.5 volt watch battery, and some electrical tape that you can make in less time then it takes to play the MacGuyver theme music.

Not apt for using with small children (because these are easy to eat) this is a good STARTER pen, but I think you will want to upgrade.

Nonetheless, these ROCK for a screen with projector and wii-mote behind, and with one in each hand... and for testing the Wiimote IWB for the first time.


1. ir led at 940 nm (i used a Vishay TSAL6400) which runs on 1.2-1.6 v costing14 centimos of a Euro, as I'm in Spain, it would be under 20 US cents , I think)

2. watch battery at 1.5 v (50 centimos/70 cents)

3. Electrical tape

4. Scissors.

5. Mobile phone with camera, webcam or digital camera (to check things out.)

Step 1: Understanding and Preparing the IR LED.

Getting the LED out.

Two basic concepts are essential.

1. The light is invisible to the human eye. (Infra-Red - below the red spectrum, the lowest visible light we can see.)

It is not invisible to a digital camera that is not protected against the IR spectrum, ie: mobile phone, digital camera or webcam, so we can use that to check things out.

2. The LED is polarity sensitive. �
You have to connect positive to positive, and negative to negative for it to work. The negative is the shorter leg of the LED. (To remember: Being short is negative for LEDs.)
Preparing the LED.

On my watch battery, the positive side was flatter. So I bent the negative side to use as my trigger.
I then made a "v" bend (two would be better) in the positive (longer) wire, that goes flat against the battery to keep the LED flat and stuck to the battery in the next step, instead of falling out of the tape.

Step 2: Bringing It Together...

Here we isolate and attach the positive ends of the LED and battery.

Keeping the negative end out of the game... tightly wrap the two positive ends with electrical tape. You could also bring in a glue gun in now to make it prettier. (but you won't be finished in under a minute)
You now have a trigger against an isolated surface, so all you need to do is...

Step 3: Cut Your Hole for the Trigger. You Are Soooo Done.

With scissors or a cutter, you remove the tape under the negative wire of the led.

The wire should be stiff enough to maintain its shape.
When you press, it should light up. Check with your mobile phone, or camera, if it doesn't check your hole, your led, and the polarity of the whole thing.

You now have an IR Pen.

Not a beauty, but you can attach it to your index finger with a band aid and no one will really see it.

If your surface is very tough and smooth, you may be able to use it as a pressure sensitive tip, but I prefer the thumb to avoid scratching stuff. (A drop of glue gun shtuff on the trigger would make it softer on the surface or your thumb. You could make a quick mold by shaping a hole in plasticine, filling the glue in, and then placing the trigger inside, to avoid isolating the trigger end. But would Dean Richard Anderson do that? NO! McGuvyer would probably substitute the tape for chewing gum, because his saliva doesn't conduct electricity.)



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    28 Discussions

    matt leddingzapper067

    Reply 7 years ago on Introduction

    I know... it is exactly swallow size for small kids.
    Have to be careful, or make a bigger pen with little peeps around.


    8 years ago on Introduction

    I found a nice "invisible ink pen" at the local Dollar Store that came with an ultraviolet LED built into the cap. It also cam with batteries and a press button to activate the LED.

    The assembly came apart quite easily - nothing was glued or soldered. I simply pulled out the UV LED and replaced it with one I had from an old remote control.

    Works like a charm but the battery life is very short.

    I intend to attach AA or AAA batteries to it somehow in the long term.

    I only mention this because it was one or two Canadian dollar(s) for everything except the IR LED, everything was included, and it was already configured as a pen.

    This is the pen in question:

    That link is provided just so you all know what the pen looks like, but I suppose you could order the pen there as well if you like.

    There are several variations of this idea out there, and a host of LED flashlights that could also be used.

    I liked this one because it was shaped like a pen and all you had to do was screw off the top and pull out the entire LED assembly, attach the IR LED and put it all back together - no fuss, no muss.

    matt leddingshakespeare1212

    Reply 8 years ago on Step 1

    um, James, or Shakespeare, I appreciate your enthusiasm, and and glad you are helping people make wii whiteboards. However, this is a website for people who like to make stuff rather than buy it. This instructable is meant as a gateway to get people making them themselves. Therefore, it probably isn't the ideal place to sell Whaleboner pens, and you might get banned for spamming. (which is a pity, because you can probably get a lot of ideas from here.) I also make custom pens, but the best IR pen is a "homemade by owner" pen.

    shakespeare1212matt ledding

    Reply 8 years ago on Step 1

    Thank you for the warning but I do make all of my IR pens myself, and setting up a Wii Interactive whiteboard, is enough of a DIY project in and of itself. Many people who are on this board also sell what they make, and where is the harm in that?

    matt ledding

    8 years ago on Introduction

    Have put up some other pens that I made, which might serve as a starting point for other creations for some of the makers here... in the last page of the instructable, they are commented on.


    Well the pen IS a bit of a joke, I should probably put up some of my more serious pens... However I put it up to show how minimalist you can go for testing the wii whiteboard ecosystem. 


    9 years ago on Introduction

    Hah I did this a fair while ago when I attempted a proper IR pen and my soldering iron fried itself (I always found that ironic). I did the exact same thing only using blue tac. Just as efficient, and as an added bonus it holds to your finger.

    2 replies
    matt leddingIzzeh

    Reply 9 years ago on Introduction

    Izzeh, that sounds faster and prettier, ... and I would add, definitely more cool than mine, if it sticks to your finger. (and I suppose you need to stick it to your finger to keep the end from coming off.) I will try it out. I love Instructables for the ability to evolve ideas... if anyone else has ideas for quick and dirty IR pens, I am looking forward to hearing them.

    the Led from the wii has a different angle of vision I think, but maybe you could... I think it'd be more expensive though... the LED is pretty cheap, and Farnell carries them if you have one in Mexico.