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Author Topic: IR Pen Improvements  (Read 17324 times)

Offline jacob358

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on: January 11, 2008, 11:31:32 AM
I wanted to open this up for discussion and investigate possible ways to improve the IR-Pen to be better received by the wii-mote.  I have seen the post on this board on adding stronger IR LED's and adding multiple LED's and I think this is a good idea but also wanted to shoot back some ideas of my own. I was considering attaching a convex mirrored disk in front of the IR-LED  to reflect the light beam back directly into the wii-mote(essentially pointing the LED at the wiimote regardless of direction). I will be trying this out sometime soon I plan to use the bottom of a beer can cut into a circle to achieve this. I will update this once I have tried.. I am very open to new ideas that could be used to improve the functioning of the IR pen.
-J


Offline atomriot

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Reply #1 on: January 12, 2008, 09:31:57 PM
in the general hardware section i posted my pens

http://www.wiimoteproject.com/index.php?topic=44.0

i used a semi transparent (fogged) cover for my LEDs so it lights up that apparatus and the wiimote picks that up WAY better than if i take them off. since my LEDs point directly at the screen and not at the wiimote

Details, details. Things to do. Things to get done. Don't bother me with details, just tell me when they're done.
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Offline cvitullo

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Reply #2 on: January 21, 2008, 10:03:21 PM
ooo you could attach the led to a small momentary switch just behind it so when you press, it turns on the led.

you'd need a hard surface though, and you'd need to press pretty hard.


Offline The Steven

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Reply #3 on: January 30, 2008, 11:39:04 PM
Here's a dumb question....

Who says the LED has to be in line with the axis of the pen?  If you have the LED facing back to the Wiimote it would be more "noticeable". 

For the pen in your left hand bend the LED back 135 degrees backwards and 45 degrees counter-clockwise from the switch (facing the front of the pen, the pen in right hand would be the same, except rotated clockwise.

My $.02


Offline atomriot

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Reply #4 on: January 31, 2008, 08:31:52 AM
you would always have to hold the pen the same way then. so when you go through the setup of the screen, however your holding that pen would need to be the same way you are holding it no matter where you are.

Details, details. Things to do. Things to get done. Don't bother me with details, just tell me when they're done.
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James Lionel Price


Offline dice

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Reply #5 on: January 31, 2008, 01:34:06 PM
What do you think about this...?

         Original                                                            Dice v 0.1

Sorry this was done very quickly in PS

You take a dermal cut the top of and drill into the LED and fill it fill it with a reflective material, (Solder, medal shavings...) something that would reflect the beam.

What do you all think about that?

Its just an idea I had when working with this problem. I think the benefits would be that no matter what angle the pen is held it would reflect more torwards the back.

Dice :)
« Last Edit: January 31, 2008, 01:36:02 PM by dice »


Offline richwhite

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Reply #6 on: January 31, 2008, 03:20:44 PM
That wold work nice ... I have also found on a shiney dry erase board the wii really pics up the IR (reflection) nicely as well .

Rich
The Edusim Project

http://edusim3d.com

Offline dice

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Reply #7 on: January 31, 2008, 04:00:59 PM
do you think a round or pointed shape would be best for the cut out?

Ill have to test it out and see.
Dice :)


Offline The Steven

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Reply #8 on: February 04, 2008, 12:48:11 AM
Quote from: dice on January 31, 2008, 01:34:06 PM
What do you think about this...?
(snip)
You take a dermal cut the top of and drill into the LED and fill it fill it with a reflective material, (Solder, medal shavings...) something that would reflect the beam.

What do you all think about that?

Its just an idea I had when working with this problem. I think the benefits would be that no matter what angle the pen is held it would reflect more torwards the back.

Dice :)

Dice, I think you're on to something there!  I've seen LEDs like that used for marker lights on cars, the primary reflector (on the LED) sends the light to the secondary reflector in the mount and then outward.

As a side-note...
Does anyone know the maximum frame rate for the Wiimote?  I was thinking of putting a 555 in astable mode in the light pens, set to different PPS rates so the software could distinguish between pens... Or using a 556, two different PPS rates could be achieved, let's say 15PPS for left click and 30PPS for right click.


Offline ZaPPZion

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Reply #9 on: February 04, 2008, 02:58:16 AM
According to Johnny Lee's webpage, the FPS/capturing speed of the wiimote's IR sensor is 100Hz.


Offline joniwan

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Reply #10 on: February 13, 2008, 09:41:39 AM
Quote from: dice on January 31, 2008, 01:34:06 PM
What do you think about this...?

You take a dermal cut the top of and drill into the LED and fill it fill it with a reflective material, (Solder, medal shavings...) something that would reflect the beam.


So did anyone try this? Did it work? Will solder grip to the LED top?

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Offline joniwan

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Reply #11 on: February 13, 2008, 09:48:09 AM
Quote from: cvitullo on January 21, 2008, 10:03:21 PM
ooo you could attach the led to a small momentary switch just behind it so when you press, it turns on the led.

you'd need a hard surface though, and you'd need to press pretty hard.

Or you can use a micro switch which is a lot more sensitive to pressure...I just ordered the smallest one I could find (8,2×2,7×10,9 mm) and I'll try it out shortly...But just how sensitive are the diodes to touch/pressure?

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Offline techie

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Reply #12 on: February 14, 2008, 04:04:15 PM
For the reflective fill of the end of the IR LED, why not use chrome paint? Spray some into a container and use a toothpick to apply it to the LED. I think I will try it this weekend if I can get a moment away from my wife.


Offline javafrog

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Reply #13 on: February 18, 2008, 06:01:15 AM
I just registered because I was going through some problems regarding the accuracy of the detected pen's location and I want to share my results with you.
First, I had constructed a single LED pen, using a high-output LED (http://www.conrad.de/goto.php?artikel=153818). It worked well for short distances (read: 1,5m), but for greater distances, the wiimote would track the pentip along a very coarse grid that reflects the angle at which the wiimote is pointed towards the surface, causing drawn lines to get very ugly (see attached file).

However, by building a second IR pen, following the "big motha" idea (http://www.wiimoteproject.com/index.php?topic=29.0), these problems could be eliminated entirely, giving me a smooth, pixelwise detection again, even for greater distances (4-5m). I hope that this information can be of some help to you (I sure wish I had it from the beginning).


Offline lderooy

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Reply #14 on: February 26, 2008, 10:31:40 PM
here is a neat idea about diffusing a LED (look at the link below referencing uchobby). If you think about the top of a LED to be like a lens of a camera then if you cut it off and maybe sand the surface, then the light might get dispersed more.  I might try this with some regular LEDS so I can see the results without using some sort of IR camera.

http://www.uchobby.com/index.php/2008/02/25/improving-the-ping-pong-ball-led-diffuser/#more-108


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