I'm trying to trigger a motion sensor on a door (for fun and to learn more about these systems) using Arduino based electronics (ca 5V, ca 50mA). According to Wikipedia, these sensors (PIR sensors, passive infrared sensors) work at >8-14000nm wavelengths - can these be tripped using an Arduino as power supply - in theory / practice, or are there good reasons why this is a futile fun experiment to start with? I'm guessing a common infrared diode will not do the trick (ca 1000nm).

  • 2
    \$\begingroup\$ use a TV remote control to try your idea \$\endgroup\$
    – jsotola
    Sep 1, 2020 at 0:54
  • \$\begingroup\$ If you are a Position IR or Remote IR newbie, you might find the following two answers useful (1) raspberrypi.stackexchange.com/questions/113016/… (2) raspberrypi.stackexchange.com/questions/103452/… Cheers. \$\endgroup\$
    – tlfong01
    Sep 1, 2020 at 2:05
  • \$\begingroup\$ I found a duplicate of this actually, @jsotola this will not work - and shouldn't - even at higher power levels. Correct me if I'm wrong but as far as I found there is literally no feasible way to generate electromagnetic oscillations at frequencies 8-14um wavelengths for electronic enthusiasts (e.g. without extremely dangerous levels of voltages) and with low power output (i.e. just enough to trip a PIR sensor). \$\endgroup\$ Sep 1, 2020 at 13:36
  • \$\begingroup\$ the sensor detects body heat, the motion of a warm object, to be exact ... maybe it can be fooled with a power resistor across a battery, or a light bulb \$\endgroup\$
    – jsotola
    Sep 1, 2020 at 14:49

1 Answer 1


These devices are sensitive at about 1Hz, try a blinking incandescent lightbulb with a reflector behind it.

If it doesn't work it might be between zones: try relocating it left or right a bit.

A person has a thermal brightness of about 100W but the reflector should boost a 3W lamp enough that it can be seen by the sensor.

  • \$\begingroup\$ great idea I will try this \$\endgroup\$ Sep 4, 2020 at 5:04

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