Youtuber sycmuzak posted this demo/explanation of his breadboarded sound circuit –

My homemade 555 timer synthesizer. I made it in about 2 hours from 2 555 timers, 4 capacitors, 1 resistor and 3 potentiometers. Schematic can be made available if demand is high enough. This is one of my first 555 timer projects, and I’m a high school sophomore, so feedback is appreciated.

It seems demand was high enough to warrant a schematic posting. Looks like fun –

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  • yachris

    But I only see two Potentiometers in the schematic, but he has three in the video…?

  • Jesse

    I think he just replaced one of those resistors in the schematic with another potentiometer.

  • TJ Arey

    What are the values for the diodes by the speaker?

    Are they just common switching diodes or do you have something special in mind?

  • Sycmuzak

    Yeah, i have three pots just for more control, take your pick on where to put it. The diodes are un-necessary, i made that schematic on a circuit simulator and it forced me to use diodes, but i didn’t use any in my actual project.

    • http://fablab-nuernberg.de Chris

      Nice Job! What are the values of the Potis? 100 Ohm or kOhm? Thanks

  • nicolas gravel

    diodes ARE NECCESARY to stop backcurrents from the inductance of the magnet in the speaker each time you switch the state betwen on and off.
    so, if you want to burn your 555 until a couple of days… use typical diodes. and study something about Lenz current in inductance systems

  • Jason Yaeger

    Kool! A DTMF generator! Add a 3×4 grid of buttons and the right resistors and you can use it to dial a phone! Or a 4×4 grid and use it to HACK phonelines!!! (Well not since the ’80s lolz)