November 12, 2008

How to make an infrared LED light pen

Simple instructions and shopping list for a great LED light pen.

If you want to experiment with Johnny Lee's Wiimote Whiteboard or other Wiimote hacking projects, I recommend starting by making your own IR LED light pen. My design shown here is sturdy, self-contained, cheap and easy to make.

Infrared LED pen for Wiimote Whiteboard



Click here for printable shopping list and instructions (PDF).

Here's your shopping list (makes 2 pens):

ITEMWHEREPART #COST
EXPO markersOffice Max21671870$6.00
IR LED x 2Radio Shack276-143$4.00
LED holdersRadio Shack276-080$1.50
SPST momentary switchesRadio Shack275-1571$3.00
N-size batteriesRadio Shack23-023$5.00
N-size battery holder x 2Radio Shack270-405$2.00
Soldering kitRadio Shack64-2802$8.00

TOTAL: $29.50

Directions:

  1. Over a trash-can remove the marker tip and core with a pair of pliers (be careful as the ink can spray a bit).
  2. Wipe out the inside of the marker to remove any remaining ink.
  3. Drill a quarter-inch hole for the pushbutton switch at the spot where your thumb naturally rests on the grip. The pushbutton is a hair larger than 1/4" diameter so you'll need to grind at the edges a bit to widen the hole until the pushbutton fits in snugly.
  4. With a fine piece of sandpaper, scuff up the surface of the LED - this helps diffuse the light to improve tracking.
  5. Remove and discard the nut and washer from the LED holder.
  6. Put the LED stems through the LED holder and slide the rubber plug onto the stems until it’s tight – having the LED on the outside of the LED holder helps more light shine out to improve tracking.
  7. Solder an 8 inch length of red wire to the positive lead, which is the longer one (you can also tell by looking inside the bulb - the positive electrode is the smaller of the two).
  8. Solder an 8-inch length of black wire to the negative lead.
  9. Thread the wires through the body of the pen and use a set of pliers to screw the LED holder into the tip of the pen. This takes SIGNIFICANT force to expand the hole slightly, but the end result is nice and snug.
  10. Fish the black wire through the hole for the pushbutton.
  11. Snip the wire about an inch from the hole, then solder that to one terminal of your pushbutton.
  12. Slip the remaining black wire back into the pen body and solder it to the other pushbutton terminal.
  13. Gently press your pushbutton into place.
  14. To leave more room for the battery, trim the excess wire leaving about an inch extending from the bottom of the pen body. Also trim the battery holder wires to about 1.5 inches each.
  15. Solder the battery holder wires to those of the pen (red-to-red!) [NOTE: this is your first chance to test your connections. The IR LED is invisible to the eye but it IS visible to the CCD of digital cameras. Point your camera at the light, press the button and you should be able to see it light up on the camera's screen.]
  16. Slide the battery and wire into the back of the pen and push the end cap back on as far as it'll go comfortably.


Good luck... let me know how it goes!

59 comments:

Jonathan Jones said...

I am a teacher and your blog has been very helpful with my research on Wiimote technology.

In your video what kind of wires did you use for the pen?

What inch drill bit did you use to drill whole?

jon139@mac.com

Ken Moore said...

Awesome - I'd love to hear more about your teaching.

Sorry, forgot to mention the wire - I used basic 20 gauge wire (http://www.radioshack.com/product/index.jsp?productId=2062656). I'm not an electronics expert, so maybe there's a better choice but this worked well for me.

The drill bit was 1/4"... you'll need to grind the edges of the hole a bit because the switch is a hair larger than that.

Good luck - let me know if you have any other questions.

Ken
ken(at)kenmooredesign.com

Ivan said...

Very nice projects, i am fascinating about all your work!! Keep going!! And Theremin i dont know what to say, fascinating... Pen ... :)) Really good work.

Anonymous said...

Awesome design and instructions. You made it very easy for the average guy to put together a homemade IR LED pen. The only thing that you might want to add though is that the LED light is invisible to the human eye. Unfortunately, not knowing this, I wasted more time then I'll admit taking it apart and putting it back together wondering why it didn't light up. {:O(

Anonymous said...

The part number and picture for the EXPO markers does not look correct. After purchasing all the items listed the battery holder does not fit.

Ken Moore said...

The battery holder doesn't fit in all the way - it's tight, and the cap will not close totally. It's a bit unsatisfying, I know. Any 1.5v battery should work, perhaps a AAA cell holder would fit?

Kevin said...

How long on average does your N-type battery last? My best guess is that my pen will be used about 3 hours a week to draw on my screen via the Wii-mote setup. The guy at Radio Shack was saying that it would run out quick. I am using a different style marker (generic big fat one commonly seen in classrooms) and have room length-wise for a AAA and the N-type holder I have is a perfect fit. the inside diameter of the pen is about 3/8 of an inch. Would a AAA last longer and if so, is the holder for one of those about the same size the N-type?

I just want to make sure that I'm getting my moneys worth paying $2.50 for a single battery when I could get a pack of AAAs for that much.

Thanks,
Kevin

Ken Moore said...

@Kevin, I picked N batteries because they're short and there's not much space in the pen body. I couldn't tell you how long the N battery lasts... but I'd be surprised if it ran out very fast. I created the pens for fun but I don't have a practical requirement for them like you do. However, if AAAs can fit in your pen's shell that sounds like the way to go.

Kevin said...

Thanks, I'll probably go with the AAA's then since they're cheaper to replace.

Brian said...

Ken, I had a bit of trouble figuring out which actual EXPO markers to use. I purchased the ones that you have listed but the tips are way too small for the LED holder to even snugly fit down in to them. I happened to have the same style in a chisel-tip laying around the house and was able to use one of these. The LED holder will still not fit very far down the tip of these either. I also ran into some issue when trying to fit the holder down into the tip. I had to twist it and thus it twisted the wires on the LED at the same time causing the whole pen not to work. Just thought I would mention the issues I ran into. I was able to get it to work; however, the tip is not down in the pen shell as far as I would prefer. I may try cutting this part back slightly in order for it to fit further in on my next one.

Ken Moore said...

@Brian - Sorry you ran into troubles. For me the "fit" of the LED holder was VERY tight - it required lots of force with the pliers to get the threading started but once it began I was able to twist and thread the holder all the way into the pen. If you come up with any worthy modifications let me know and I'll amend the post.

Erin said...

Ken, your directions for making a sturdy IR pen are the best I've seen. I am very pleased with the IR pens I made and look forward to using them in the classroom. To say the LED holder fits very tight is an understatement; that is the most difficult part of this project (fitting it on the pen tip), but with MUCH patience (and sore hands)it is possible. Thanks again and happy New Year.

Anonymous said...

I followed your instructions, then instead of the LED holder, I applied some super glue, held the LED in place for a minute... from there I followed your instructions... I too chose to use a AAA battery.

Nice instructions and video ... thanks!

Bruno Duarte said...

hi,
i'm curious about how do you use your pen in a graphic software as you show at the beggining of the film. Would you make a tutorial about that?

tks

Bruno said...

hi
Iam starting little procjets with IR and i would like to know how do you use the ir pen in graph programs like in the beggining of the video.
Tks!

Andi said...

Hi Ken! I just finished making two pens with your help. Thanks so much for all of your help. I am now going crazy with my Wii board! Super!

Ken Moore said...

Hey Bruno, you can find more info on the Wiimote Whiteboard, including the code to make it work, here: http://www.cs.cmu.edu/~johnny/projects/wii/

Anonymous said...

hi ken, i would like to know, are you using the same software that is given by johnny lee.......

horatio said...

Hi ken........ i would like to know are you using the same software that is given by johnny lee........

Ken Moore said...

Yep, same software as Johnny Lee.

Marisa said...

We tried to make a version of your pen -- no Expo markers so we used some pipe which meant that battery pack was hanging out of the pen. The adaption we had to make was we used a double A battery pack (2 batteries) because that was the smallest thing our Radio Shack had (it is still 1.5 volt). Alas the pen does not work. Do you have any great troubleshooting techniques?

Ken Moore said...

@Marisa, 2 x 1.5 volt batteries = 3 volts... you may have blown the LED? Also make sure to use a digital camera to check if the LED is on or not -- the human eye cannot detect the infrared light, but it does show up in the viewer of a digital camera. Thirdly, make sure you have the polarity correct (you can try swapping the polarity to double check).

Marisa said...

Sorry I used AAA not AA. Do you mean the polarity of the bulb?

Anonymous said...

I am a teacher and my class tried making the pen today using your video instructions - it went great! I bought the smaller size pens, but luckily had Highlight Pens also which worked really well and are cheaper.
Thanks for the video!

Sue said...

Thanks for both the video and the Radio Shack shopping list! I used a regular dried up EXPO dry erase marker, and it worked fine. You weren't joking when you said it took some force to get the LED holder in the tip. I used the drill to grind down the inside of the tip a bit to make it a little more receptive. It seemed to help. Given the bulge the LED holder produces, I'm impressed with the quality of plastic used by EXPO! For those of you wanting to use this for presentations, check out Classroom Presenter, a free program developed at the University of Washington. It's designed for TabletPCs, but I think it will work great as a 'smartboard' application. You might also want to check out
Smoothboard
as the software interface for your Wii remote. It's has more functionality than Johnny Lee's original software.

kingworks said...

I followed your instructions and have a working pen. When I connected it to the software, I noticed the battery started getting really hot, so I added a 2.2ohm resistor and the heat is no longer a problem.

Unfortuantely, the Wiimote seems to have trouble seeing the light from more than about 1.5 feet away. Is there a way to 'pump up' the output of the light? I'd like to get about 40 - 60" working distance, if possible.

Ken Moore said...

@kingworks, not sure why your battery got hot - I haven't had the same experience, but sounds like you solved that issue. Regarding visibility / distance, have you scuffed up the LED to help diffuse the light? I don't know if the resistor might be interfering with the LED's output, or perhaps you should consider ordering TSAL6400 LEDs from vishay.com -- I've found these to be brighter than the Radio Shack ones.

kruz said...

LED HOLDER:
Like most people I was struggling for a while with the LED holder. The way I finally managed to do it was to get an LED holder without the LED in it and thread it all the way through. I didn't have the wires in the way and I wasn't worried about breaking the IR LED. Once I put the LED with the holder, it was still 'tight' but it went through all the way much easier.


BATTERY HOLDER:
I wanted to use AAA batteries cause I have rechargables and they are exactly 1.2 volts. The AAA holder I bought didn't fit so I sanded it down... I also had to remove some of the plastic in the cap, to get it to fit without being tight.

-Kruz

Cole said...

Hey Ken, I love this whole guide. I'm actually doing this for my science fair project, and the research will be how IR lights work and how you can make your own smartboard, etc. I'm going to radioshack soon for all this stuff, and I'm going to use a fat expo marker so the battery fits. I was wondering though, if it was possible to use a rechargable N size battery with soldering tabs, and make the pen rechargable through the back end in some way. If it's no inconvenience to you, I was wondering if you could post here some suggestions or even email them to me at musicxbballfreak@gmail.com. I feel that using a rechargable n would be easier, provide a better fit, and the pen would be much more official. Thanks for the awesome guide.

Anonymous said...

You need to use a resistor with LEDs. LEDs are not light bulbs, they need a way to dump the current as heat.

Anonymous said...

Any idea on what kind of resistor?

iliosporos said...

Hi. nice work. What type of ir red do you use?

Ken Moore said...

The LED I use is a TSAL6400 from Vishay electronics:
http://www.vishay.com/docs/81011/tsal6400.pdf

I'm not an expert in these matters but all the Wii hacking forums recommend this LED and it seems to work well for me.

Mike said...

HI Ken,

Thanks for the tutorial, it was great- I only have one problem though- when I put the battery in, the light is always on, and pressing the switch down turns it off. This is the exact opposite of what I want. Any thoughts on why that might be? Thanks in advance!

Mike

Ken Moore said...

@Mike Hi there, I encountered the same problem early on, then I found out there are two types of switches: N.O. (normally open) and N.C. (normally closed) where pushing the button invokes the other state. See http://en.wikipedia.org/wiki/Switch Sounds like you inadvertently got the wrong type.

Anonymous said...

Hi Ken! I'm a graduate student of education at Rutgers University in New Jersey. I have a question for you: what is the chance that someone could rig up an infared laserpointer so that you could control your "Johnny Lee-style smartboard"? I looked on youtube for information about how to build infared laser pointer, but aparently they're popularly used to burn things. Are infared lasers always destructive, or could I really make a laser pointer to control my computer from across a classroom?

-borrowbreadcat

Ken Moore said...

@Anonymous, sorry I've tried experiments with laser pointers and the Wiimote doesn't recognize the dot (because it's red, not infrared). It would definitely be cool, but the technology isn't compatible.

borrowbreadcat said...

Well the reason I asked is because you seem like a pretty resourceful and electronics-handy guy. So what I meant was to ask if you could concieve a way to rig up a laser pointer which in fact emits infrared instead of visible light. My hope would be that the beam is intense enough that the point where the beam is refracted on your screen is intense enough to be picked up by the Wiimote.

Ken Moore said...

@borrowbreadcat a quick Google search shows that there are IR laser pointers out there, so it could be done... but I'll have to leave the ingenuity to you since I'm a new father and have another priority for the next 18 years :)

PB said...

Thanks for the easy instructions! Never used a solder gun before and it took me 30 minutes to make my first pen and worked like a charm. I had trouble finding the pens you had posted. So, I tried a different one that is longer and the LED Holder fits perfectly in tip of the EXPO Click pen, you don't have to worry about it being to snug. Others may want to try that pen. http://www.officemax.com/office-supplies/pens-pencils-markers/markers/dry-wet-erase-markers/product-prod2040157

Ken Moore said...

@PB Thanks for that tip! I've added the info to my video and text instructions.

Amir said...

hi ken,
im thinking about starting this project, im still kind of confused about the type of switch i need 2 buy, is it the normally open switch http://www.radioshack.com/product/index.jsp?productId=2062546

Ken Moore said...

@Amir, yes, the normally-open switch is what you want. That way when you're not pressing the button the light is off, and vice-versa.

David Fountain said...

With regard to the distance that the wii remote can see the IR dot we at <a href="http://www.irpens.co.uk>irpens.co.uk</a> have found that the genuine Nintendo wii remotes have a far greater ability to detect at distance. We've tried about 8 or 9 third-party remotes and none of them are very good beyond 6ft, the genuine remote we place several meters further - which of course gives a greater field of view.

janoo said...

sir it was awesome
plz rly my comment
my doubt is that this work on every screen without any intermediate thing
my mail@ is rahman_janoo1992@yahoo.com

G3TT3R said...

I honestly have no functional use for an IR pen but I'm really interested in light drawing. Do you think that your IR pen model would work for an actual LED light pen? Granted an LED light does need a resistor, I'm sure the Expo pen you've used would provide ample space for it, I was just curious to your thoughts on this. I will say that you have a great inventive mind and I hope to see more things come from your brilliant mind. Btw, congrats on the new addition to your family.

Ken Moore said...

@G3TT3R Oooh, light painting, yes I think this pen would be ideal for that. Aside from adding a resistor everything else would be the same... if you create this please post some photos and I'll link to them. Re: daughter, thanks! She's 1 year old now, doing great... teething aside :)

Anonymous said...

if you want to check if the IR led works, use the camera on your camera phone.

jamesalli said...

can you a different battery other then n size

Ken Moore said...

@jamesalli yes, I only used a 1.5v N size battery because it's shorter than a 1.5v AA and fit into the pen case wel.

Rachat de credit said...

Thank you it has been a very good guide, now to make an infrared led light pen is definitely very easy with the help of your recommendation. Thanks

Anonymous said...

Thanks for the easy instructions! Never used a solder gun before and it took me 30 minutes to make my first pen and worked like a charm. I had trouble finding the pens you had posted.

led par lighting

led par 38 said...

Thanks for information you've share, and its very very helpful to other like me .. good job I can wait for another teaching from you.

Led Holders said...

Wooah You just gave me a really nice idea that i can also do my self thank you for sharing! =)

Anonymous said...

Thanks for your video! Helped a bunch!
Heres my pen

http://imageshack.us/photo/my-images/805/irpen.jpg/

Ken Moore said...

@Anonymous ... looks great! Glad the tutorial was helpful.

John Connolly said...

Hi, I had two questions:

I have a PC laptop, and i connect my laptop to my lcd tv. Can i use a pen on the TV or does it need to be right on my PC screen?

Also, does the pen work on a laptop?

Thanks,
jmconnolly.lsma@gmail.com

Ken Moore said...

@John Connolly you can "draw" on any surface where you do the calibration step. It could be a wall, though the down side there is you wouldn't see visual feedback like when you "draw" on a computer screen or tv.

Printed Circuit Board said...

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