5N30.50 - Hearing Infrared

Code Number:
Demo Title:
Hearing Infrared
Infrared Spectrum
Area of Study:
Remote Control with Infrared LED, Radio Shack Amplifier/Speaker, Solar Cell, and IR Filter.

Aim the remote control at the solar cell and listen to the pulses that are emitted.

An interesting demonstration is to aim the infrared remote control at the solar cell and hear the pulses and then insert the IR filter in front of the remote control to absorb the signal.

NOTE: The IR filter from a 35 mm projector seems to work best.

  • Jennifer Birriel, "Digital Imaging of Infrared Light: Digging Deeper", TPT, Vol. 58, #2, Feb. 2020, p. 138.
  • Ernie McFarland and Tom Kehn, "Seeing Infrared", TPT, Vol. 38, #5, May 2000, p. 314.
  • James O'Connell, "Decoding the TV Remote Control", TPT, Vol. 38, #1, Jan. 2000, p. 6.
  • Harry Manos, "Hearing Infrared", TPT, Vol. 35, #9, Dec. 1997, p. 552.
  • Stanley J. Micklavzina, "Tricks with Invisible Light", Physics Education, Vol. 38, #6, Nov. 2003, p. 492.
  • Mark Davids, etc, "Pulse-Code Modulation", Teaching about Lightwave Communications, 1994, p. 3-28.
  • Rick Beyer, "Surfing Safari", The Greatest Science Never Told, p. 168.
  • Brian Jones and Matt Fackelman, "Remote Tones", Don't Forget the Duct Tape, p. 121 - 124.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.