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I'm currently using a photodiode (found here) along with the appropriate emitter to send data between mobile robots. I'd like to the sensor to optionally be used as an ambient light sensor using a filter with lower sensitivity.

My trouble is picking out what this "ambient light" should be. Since the photodiode is only sensitive between 750 and 1150 nm, I imagine I need an IR bulb. However, every IR bulb I look at doesn't seem to specify what wavelengths it outputs. They also seem to all be used as heat sources, which I'm not sure I need. Ideally I'd like a cheap option that I could just stick in a lamp, but I'm open to other ideas. Does anyone know where to buy the correct IR bulb? Or what the correct IR bulb would be?

Thanks!

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  • \$\begingroup\$ you have gone down the bulb source as research to a question and then asked about it. This is common, but I think you will get the best help if you ask about what you technical problem is. \$\endgroup\$
    – Kortuk
    Mar 20 '11 at 17:37
  • \$\begingroup\$ By "IR bulb" do you mean a heat lamp, or something else? Most heat lamps have the vast majority of their radiation output at wavelengths much longer than IR LED's. \$\endgroup\$
    – supercat
    Mar 20 '11 at 18:51
  • \$\begingroup\$ @wcmartin - Any special reason you want a bulb and not an IR emitter? (aka IR LED) \$\endgroup\$ Jul 18 '11 at 15:58
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I figured I should post what ended up working for me. Someone suggested I just use a typical 100 Watt incandescent light bulb, so I did. It worked great and gave off the right amount of IR for this project. I imagine an IR bulb would have been overkill.

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    \$\begingroup\$ or the IR bulb would be much lower wattage. \$\endgroup\$
    – Kortuk
    Jul 18 '11 at 8:11
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Would a bunch of high power IR LEDs do? 850nm LEDs are common and easy to get hold of.

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  • \$\begingroup\$ You are writing an answer, if the question is not clear ask. It might be important to ask how much light is needed, but your answer could be much better then asking the OP(Original Poster) another question. \$\endgroup\$
    – Kortuk
    Mar 20 '11 at 8:47

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