Smartled progress and work stuff

Apr 01, 2010 13:35

Most productive week ( Read more... )

geekery, smartled, work

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richdrich April 1 2010, 03:16:13 UTC
Video added. I need a proper camera.

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randomdreams April 1 2010, 03:56:24 UTC
How are you going to have them communicate with one another? We've been spending a lot of time building communication systems between LED drivers and have largely settled on zigbee/xbee, although I'm still arguing that using the LED's themselves as transmitters, and possibly even as receivers, would have a lot of advantages.

Sorry to hear about VB, but paychecks are always nice.

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richdrich April 1 2010, 05:59:40 UTC
Depending on bandwidth/noise margin etc, either async over power, async (transmit only send-and-pray) or SPI.

The idea is to make something for a shipping price of well under USD10, and dimensions around 10mm square. which doesn't leave much room for a wireless transmitter.

The idea of having the LEDs talk to each other in a mesh is very cool though. How would you make a LED receive? Also, they would have to all point at each other.

(Also, a R+G+B+infrared led would be useful in this context).

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randomdreams April 2 2010, 02:39:47 UTC
It is apparently possible to measure a voltage across an LED that is off and getting illuminated by another LED of roughly the same or shorter wavelength: they work as lousy photodiodes.
I haven't actually TRIED this, but I've been told it by people who should know.

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richdrich April 2 2010, 02:55:49 UTC
Not with a cheap (10mV res) multimeter, it isn't.

(Just tried it with a couple of red leds).

But maybe a more sophisticated experiment would reveal something..

On a related topic (wireless), I have need of a Bluetooth transceiver where I can provide the packet datastream myself, using hardware. This is for an attempt at low-latency digital audio. I found the AT86RF212 Zigbee device, which would be great, except it's too slow. I need idealy 2Mbps.

Any places I should look?

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