myDAQ Laser Listener

myDAQ Laser Listener

Build the ultimate spy eavesdropping device and explore the fundamentals of waves. Using myDAQ and a laser, measure vibration and then convert light to sound.


The Laser Listener is considered by many to be the ultimate spy tech device, giving the user the ability to listen in on conversations that take place in a distant building without having to install a bug or transmitter at the location. Said to be invented in the Soviet Union by Leon Theremin in the 1940s, Theremin’s original system could detect sound from a nearby reflective surface by picking up faint vibrations.  It is rumored that the KGB used this device to spy on the British, U.S., and French embassies in Moscow.

Using Theremin's original designs, you can build you very own Laser Listener to hear the vibrations from any shiny surface.  You will use LabVIEW and the NI myDAQ to record the sounds, filter them, and play them back. Through this project, you will learn about lasers, reflection, vibration transmission, electronics, and filtering.


  • NI LabVIEW for Education software
  • NI myDAQ hardware
  • NI myDAQ Protoboard
  • Laser Pointer
  • Photodiode
  • Op-amp (e.g. LM431)
  • Resistors
  • Capacitors
  • Mirror (optional)
  • Speakers (optional)
  • Polarising filters (optional)


  • Computer Science - Through studying LabVIEW code, students will understand loops, queues, state machines, even structures, and parallel architectures in programming.
  • Sound & Wave Theory - Students will learn about the properties of reflection, diffraction, and wave behaviour used in audio and optical engineering.
  • Analysis Techniques - Students will be able to see the acquired data and analyse the properties of the audio wave.
  • Audio Analysis - An introduction to signal-to-noise ratios and audio quality can be seen as the placement and alignment of the laser pointer beam changes.
  • Filtering - Through the LabVIEW Express VI programming interface, students will learn the effects of filtering on sound waves.