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Author Topic: Picking the right photodiode  (Read 396 times)
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Congo
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I need to transfer data from my Windows Phone 7 to mC. The problem is that WP7 doesn't have any type of usb client control. So I was thinking, I could connect photodiode to mC, change in voltage will be used to represent data. I have already coded 32 characters using two voltage states, that should be enough. Light will be emited from WP7 screen, just flashing black/white when in sending mode. I would isolate external by building a stethoscope-like fraim for diode. My question is what model of photodiode should I use? Changes in screen light will be every 20 ms. Do I need some kind of amp for voltage from diode ? 
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Dubuque, Iowa, USA
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I'd start with any IR phototransistor you can get your hands on; basically whatever is available at the local electronics store. A round/5mm instead of a rectangular one would probably be the best. If you can isolate it well and you're holding the phone closely you shouldn't have a problem.

If you can get your flash rate up to around 38khz then you could use an IR receiver and you'd have the amp built in.

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Congo
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Thank you for replying. What kind of amp circuit should I build? Would something like 741 DIP OPAMP, 3-18V, 1MHz, GENERAL PURPOSE, DIP8 be useful?
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