Instructables

Robot Voice Changer without using IC's?

I want to make a robot voice changer circuit but it seems that the IC's are not available in our country. Is it possible to construct one using transistors instead?

What you want is some sort of oscillator that you can use to modulate the voice. Here are 2 to choose from. Now, take the output from the oscillator and feed it to the 2nd section of this schematic (after the 555 timer output) and you will get to choose from 4 different modulation waveforms. Finally, feed that output to another transistor that is biased to just the turn on point (approx. 0.6V)  so that you can feed your voice into that Emmitter/Collector (depending on what you use, NPN or PNP) and control it's modulation at the base.

What you end up doing is chopping the voice into parts of it's original form, losing half of the modulation signal. That gives you that staccato sound of a robot.

I highly reccomend you get a circuit simulator. That way, you can tweak the values of a circuit to see the outcome without building it in the real world. You can get the free student version of Circuitmaker here. Of course, you may get any other that you would like.

Good luck,
Qa
rickharris2 years ago
Yes

http://www.instructables.com/id/Build-an-analog-vocoder/
Sure. Find all the info you can on the IC that would be best for your voice changer. If you can get enough info on it you can reconstruct the IC with basic through hole components. Just be ready for it to be a rather large circuit.