[Chris] at PyroElectro sent in a great 8-part write-up of a miniature infrared theremin.
The theremin is based on a PIC microcontroller and an infrared distance sensor. The build log goes through the theory of operations for the IR sensor and tone generation. [Chris] definitely does a great job showing the math that went into the design.
Although this project isn’t a true theremin because it operates on light like a few other projects we’ve covered in the past, it’s easier to play because of the hard-coded notes. The build does show some promise though – he could likely expand it to use more accurate ultrasonic sensors or use, “two proximity sensors, one for treble and one for bass like an accordion.”
The theremin is usually played with both hands providing a continuous pitch and volume. This project features hard-coded, discrete notes, so we’re wondering about the possibility of implementing MIDI on this IR theremin. The original MIDIbox was based on the same microcontroller as this project, so it’s definitely a possibility.
Check out the video of the theremin in action below.
[youtube=http://www.youtube.com/watch?v=K6bF3Q_YM68&w=470]
related link: http://gieskes.nl/instruments/?file=wavetable-radar
That’s… not a theremin. It doesn’t play in a very similar way at all, and it doesn’t operate by the same principles. Folks like to call anything they can wave their hands around in front of and makes a noise a theremin. In that case, most small children and some pets are also theremins.
Interesting project, in fact, but not a theremin.
Karate chop music !!!
MIDI, being about 30 years old and not changing one bit is pretty easy to implement. It’s ttl serial at a funky speed with a simple op code that says what channel and note/cc and after touch.
a ‘real’ theremin is a real interesting instrument from a historical and analog systems standpoint. I can see how an IR theremin to a heterodyne theremin is as different as a guitar is from a ukulele or a violin but until there is a taxonomic definition of hands free electronic music instrument I think IR theremin isn’t misleading. As far as a novice sees is a music box that you don’t touch.
OTOH don’t call my euphonium a french horn or a trumpet and don’t tell me that it isn’t a tuba.
I built a cheap optical “Theremin” using two 555s and 7 other components. Its based on a design by Forrest Mimms III from a old Learning Electronics book. http://themakersworkbench.com/?q=node/309
Bassackwards “keys” for starts. When it’s as analogue as the voice, that’s when it gets fun!