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Topics - micbridge

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IR Pens / Meet Pixel - a small and clean LED pen
« on: May 26, 2008, 01:59:06 PM »
I wanted to share the second incarnation of my side-mounted LED pen. I always wanted to make a mini-LED pen for use at my desk since I started this crazy project in March.

I took a small laser pointer, cut off the laser diode, and then attached leads to the provided switch(negative end) and case (which carries the positive). Using a Vishay TSMF3710-GS08 surface mounted (SMT type) LED I was able to solder the leads coming out the end and fold the LED over to form the point. See pics below...

Link to my Picasa page for more on this and other wiimote projects:

IR Pens / Side-Mount LED test
« on: May 17, 2008, 05:09:07 AM »
Prompted by benpaddlejones' "Summary of IR Pens & Interactive Whiteboards that work" I did some wiimote testing at work. I used blank slides in powerpoint and wrote on the screen with different distances and mounts for the wiimote. I found the side-mount pen to be most effective even out to 15 feet. The wiimote really starts to lose resolution after that. The wiimote did pick up the single side-mounted Vishay TSMF3710-GS08 IR surface mounted (SMT type) LED at 15 feet, but you could tell that it worked better with two side by side LEDs to make a bigger IR blob for the wiimote to track. (thankyou gabort for pointing this out in your post 'big motha') I've posted the powerpoint slides below for your review. The fun thing was that people kept stopping by to play with the wiimote whiteboard so some of their diddles are included.

Here is a link to the side-mounted pen approach:

IR Pens / Side-Mounted LED - a whole new approach
« on: May 11, 2008, 05:36:03 AM »
Hey gang. I've been working on a new pen concept that would fix the traditional problems with the original IR LED design: forward facing LED, IR wavelength not optimal, one LED not powerful or large enough. I found a different kind of LED light at that is smaller and flatter then your traditional LED. (see mouser link below) You can fit three of these across a dime and when you lay them on the table the light would shine up towards you not to the side. Their wavelength is 870nm which I understand from this forum is right where the wiimote is most sensitive to IR light. The old Vishay TSAL6400's are 950nm which work but I wanted every advantage when trying to get my wiimote to pick up the IR light.

So I set out to get these and put them on a previously made pen. I used the online LED calculator and got my new resistors (10 ohm 1/8 watt). The little LEDs were difficult to solder because of their size, but the end result was brilliant. Too bad I'll have to wait till work tomorrow to try them out. I expect great things however because if the old style pen kinda worked, this pen has got to give the wiimote a definite light source to follow.

I'll return and report how it performed, meanwhile please link to my Picasa page to view photos and specifics on the pen and the new diodes. Look at the second half of the photos to see the new diodes.

One last thing. I planned to make two pens: one large format pen with four leds for presentation use with a projector, the other will be a very small slimline pen for use at my desktop monitor using only one of these diodes for Photoshop work.

Project Ideas / Universal Wiimote Mounts
« on: April 22, 2008, 09:00:56 PM »
As I go along the wiimote white board development process; making pens, getting the bluetooth to work, I've had a couple epiphanies on wiimote mounts that I'd like to share. Having an amature fascination with electronics AND neodymium magnets has actually paid off. Skip to the bottom if you need links to pictures....

First, a 'universal' non-invasive wall mount for the wiimote: Get a strong 3/4"x1" neodymium magnet and run it along a gypsum bd partition wall. You will soon find that the magnet makes a terrific stud finder. In fact, the magnet 'sticks' to the wall grabbing the screw in the gyp bd with great tenacity. Next, get yourself a short, cheap 6" camera tripod from Radioshack. Extend two legs of the tripod and then put the third 'short leg on the magnet on the wall. Click! Now, glue a 1/4" nylon nut from Lowe's on to the bottom of your wiimote around the center of balance (roughly below the speaker on the top side). I used Gorilla glue to great effect and let it setup overnight. You can now screw the tripod into the base of the nut glued to the wiimote. Now any nearby wall can support your wiimote for whiteboarding!

Second, and along similar lines, you can hang your wiimote from just about any ceiling. I am working this project for the exclusive purpose of developing a portable wiimote whiteboard for our architectural practice. As such, we make most on site presentations in boardrooms with acoustical tile ceilings. The grid of said ceilings are made of steel. If the magnets work for the wall, then they can also work for the ceilings. Buy yourself a telescoping pointer with a neodymium magnet on the end. You know the kind, they are at hardware stores and used generally for fishing keys out from behind refrigerators. Remove the screw from the non magnet end and remove the pocket clip, halfway screw the end screw back into the telescoping pointer. Get a paper clip and bend it straight, if that makes sense. Then twist the center part of the paper clip 360 degrees around the screw post and tighten the screw. Take some time and bend the paper clip down into two separate 'L' shaped legs that will snap into the grooves on the sides of your wiimote. If you do this well, the paper clip will have pretty good holding power on the wiimote. Now, extend the magnet end of the pointer and click it on to the metal runners on your acoustical tile ceiling (ACT). Now you can have great flexibility in placing your wiimote to face the screen without undue setup time or damaging your client's boardroom with tape. If you do not have an ACT ceiling to work with, pull out that 3/4"x1" neodynium magnet you used on the wall earlier. snap it on top of your pointer magnet. Run the magnets along your gypsum bd ceiling and sure enough you will find a screw and the whole apparattus will hold there in mid air. It is pretty cool to see your wiimote setup hanging from a smooth ceiling.

Here is my Picasa page cataloging my wiimote progress. Near the end you will see video showing how these mounts came together and what they look like. The best part for me is you can still set up the wiimote with all its parts and two mounts in the palm of your hand.  :)

IR Pens / What am I doing wrong?
« on: April 02, 2008, 07:15:52 PM »
I've got two AA's in a pen in series. I know juice is flowing because it lights up an incandescent flashlight battery great. I have the very Vishay 6400 IR LEDs That are recommended. I have a 1/2 watt 16 ohm resistor on the positive side of the LED. I know power running through the LED because I can feel the heat after a few seconds.

After so much tweaking and fabrication I feel disappointed. Is the problem the 1/2 watt resistor?

IR Pens / Energizer cell phone quick charger as IR pen
« on: March 30, 2008, 08:27:29 AM »
I have been working on my IR pen and am enjoying the challenge. I was just at the store and I saw one of those energizer cell phone quick charge packs and I thought Man! Batteries, Button, in a clean little pack. If I am successful in getting this wiimote whiteboard to work and the folks at work want me to make more I'm going to try converting the battery charger.

Anyone have any additional ideas or comments?

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