Use an LED as a sensor

in LEDs, sensors by DP | 4 comments

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 in LEDs, sensors and tagged , .

Comments

  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?

Leave a Comment

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Notify me of followup comments via e-mail. You can also subscribe without commenting.