Sunday, October 20, 2013

Propeller Chip Tiny Digital Recorder

Demo Board rev D, E, F, click to enlarge

Set up a Parallax Propeller chip with microphone in and speaker out (or run code on the Parallax Propeller Demo Board) to enable a digital recorder for a few seconds of sound record and playback, much like a unit sold at Radio Shack.

"It records one second of sound into the Prop's RAM (no SD card etc. needed), then plays that sound when another sound exceeds a sound threshold."


The code is provided by Raymond at the Parallax Forum. "It uses the demo board's microphone (voice activated) to record·a second of audio. Then, it plays it back out the speakers a second later. After this, it will randomly either repeat or record again. Of course, this idea could be extended into a WAV recorder... This works good for recording something short like "Boo!" for Halloween effects. Nothing else is needed to store the record except the Prop chip itself. You don't have to have it say "boo" to be a Halloween feature... just a mysterious parrot.. unseen, but heard will offer up lots of fun. Just make sure that the mysterious parrot is loud enough, but coming from an impossible to determine source (maybe a ceiling speaker). Play with the timing and have it be a weird echo of sorts."

File Type: zip‎ 18.5 KB

Beau Schwabe offers a variation with ECHO capabilities used in a Halloween application. "I was playing around with this object a little bit tonight for a Halloween prop, and I figured out a way to really sustain the echo for long periods of time (about 20 seconds). When you adjust the bit resolution, you can really get some funky robotic to large auditorium sound effects..."

Propeller Echo Test - Happy‎ 1.89 MB‎ 1.89 MB
Propeller Echo Test.spin‎ 3.9 KB‎ 568.2 KB‎ 591.3 KB

For downloading a schematic that includes revision G:

Microphone-to-VGA demo in the OBEX.