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Use an LED as a sensor

Posted on Tuesday, February 4th, 2014 in LEDs, sensors by DP

img_4840

Michael Beyhs shows us how to use an LED as a sensor:

How the code works:

  • Configure all analog inputs to outputs and pull low to turn on all red LEDs.
  • Turn one analog input pin into an actual Input and read the amount of light that is reflected into it.
  • Turn that input back into an output and continue on to next.
  • After all inputs have been read adjust the PWM of the blue LEDs according to the amount of light that was measured.
  • loop forever…

Via Hacked Gadgets.

This entry was posted on Tuesday, February 4th, 2014 at 7:00 pm and is filed under LEDs, sensors. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

4 Responses to “Use an LED as a sensor”

  1. Carl Hage says:

    The usual (more sensitive) method of using an LED as a light sensor is to charge a diode with a reverse bias, then measure the time it takes to discharge. If the LED is used as an emitter and sensor, then 2 ports are needed to be able to forward bias as an emitter and reverse as a sensor. Search “led light sensor” or “forrest mims led sensor”.

  2. steves says:

    Besides light, what is it sensing?

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