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Topics - Gavin

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Programmers Den / Bluetooth Programming with Windows Sockets
« on: March 20, 2009, 02:06:12 AM »

Anybody working on Bluetooth Programming with Windows Sockets yet?
The old WIDCOMM stuff is too slow and you can't buy dongles that support it for much longer.
Broadcom bought WIDCOMM and M$ built a better faster stack. (Well more tenaciouls anyway, once you have it on VISTA you can't easily get rid of it.  Yes I know you can eventually, but then the old BTW5 stack won't connect to new dongles.

http://msdn.microsoft.com/en-us/library/aa362928(VS.85).aspx

I can help with a walk through, but I'm not able to start this project now.

G

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IR Pens / TSAL5300 v.s TSAL6400
« on: March 15, 2009, 10:40:19 PM »
An update on TSAL5300 v.s. TSAL6400.

Based on the spec sheets, I think the TSAL5300 is actually a newer as well as a better part than the TSAL6400
bigger numbers aren't always better or all part numbers would be 99999999999 by now.

The 5300 actually has cleaner lensing than the 6400, so though it's only +-22 deg
v.s. the 6400 +/-25 deg, the 5300 will give more even illumination.

Look at Fig. 9 - Relative Radiant Intensity vs. Angular Displacement
here:  http://www.vishay.com/docs/81011/tsal6400.pdf
v.s Fig. 9 for the 5300
http://www.vishay.com/docs/81008/tsal5300.pdf

As far as intensity goes, the 6400 specs min typ max at  25 40 125 mW/sr
while the 5300 is  30 45 150 mW/sr  so 5300 is slightly brighter.

They are both 940 +/-50 nm so same wavelength

If you need wider angle you can flatten or rough up the LED
Flatten and polish you can get +/-50 - 80 depending on where you do it. (cut the top off square)
Roughing with sandpaper, even 600 grit, will just make the light scatter everywhere and make it dim.
You want wider angle and brighter? go with a VMSx nnnn where x is B F G S etc determining wavelength, and the number "nnnn" will give you some variation in brighness, they are all 100mA flat lens PLCC-2 package LEDs


G

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IR Pens / Re: Vishay TSAL6200 - Can it be used
« on: March 14, 2009, 10:19:07 PM »
I've been investigating what IR LEDs Vishay makes to see which would be good for IR pen.

You want a wide angle so if you tilt the pen it still works, but you also want it bright enough.
The wider the angle the light is disbursed over, the less intensity at any point (i.e. the camera)
It's just like spraying a garden hose: on JET all the water goes to one place, but you have to point it.
on spray everything gets wet, but not a lot.
TSAL6400 is 25 while TSAL6200 is 10   ... btw, TSAL7400 is the same as the TSAL6400, but in a clear case.

Another consideration is wavelength of the light (nm) Wiimote can't see light we see or it would have too much "noise" to find the signals. Human vision sees from 400nm to about 760nm. Most of you have been using 940nm LEDs, I know the filter in front of the IR camera blocks to about 800mn, (has anyone measured it's absorbtion spectrum?). The thing is 830 to 890 nm LEDs are available and some are brighter (there is also better quantum efficiency, both in making the light in the LED and absorbing it in the camera), so 850nm and up should be fine. Let me know if anyone knows differently.

Anyway because everyone who isn't making IRpens for Wiimotes is busy lighting up security cameras, ;-)  there are lots of bright IR LEDs, many new to the market:
Here are a few to try in decreasing order of preference: (Get the one you can find as close to the top of the list as you can.)
TSAL6400   T-1 940nm   25    40mW/sr
TSAL7400   T-1 940nm   25    40mW/sr
TSHF5210  T-1  890nm   22  180mW/sr
TSHF5410  T-1  890nm   22    70mW/sr
TSHF6410  T-1  890nm   22    70mW/sr
TSHG6400  T-1  850nm  22    70mW/sr
TSHG5510  T-1  830nm  38    38mW/sr   Really wide but less bright, good in small room.
TSAL7600   T-1 940nm   30    25-75mW/sr   wide, less bright, good in small room, or with multiple cameras


If you are making a stick with the LED on the back and camera behind you
or to the side, try these surface mount chips, wide smooth beam, but flat top so not good for a pen.

Vishay VSMG3700    850 nm    60    10 mW/sr
Fairchild QEB421      880nm     60         48mW/sr


If you want to do the Johnny Lee tape on your fingers and wave your hands to make music or draw or whatever, you want a source of light that is a narrower beam, and you will need lots of LEDs to make it bright try these:
TSFF6210        870nm      10          90-180-450       


Forget most of the Lite-On and Everlight LEDs they are too dim, except
Everlight HIR5393C-L223  10mm  850nm  25 deg  150-200 mW/sr
A big 10mm LED that's really bright.

Gavin

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