Thursday, April 08, 2010

DIY 8-Step Waveform Editor




This is an example application of using the previously-mentioned 8-slider thingy. An analog waveform can be changed by changing the position of the sliders. The sliders represent the shape of the waveform. This is achieved by multiplexing the resistance of each slider in sequential order, then outputting to a voltage divider. An 8-way analog multiplexer is used, as well as a binary counter and a simple square wave for timing generation.

The schematic is given below. Note that the pots are incorrectly labeled as 10k, although 10k pots are fine.

9 comments:

aggaz said...

Nice! Have you a schematic?

Sebastian Tomczak said...

updated with schematic :)

Gottfried said...

should these faders be linear or rather logarithmic? thanks!

Sebastian Tomczak said...

I used linear.

Jacques Laroche said...
This comment has been removed by the author.
Brett said...

I would think for this schematic, linear would be preferred to manipulate the voltage of an 8 "point" waveform. If this were altering the pitch of an oscillator, logarithmic would seem to make more sense, and give you more dynamic range.

Danny Cisco aka. Neutro said...

This is just what I have been looking for!

l'd love to have 2 of these in a modular with CV or MIDI control.

Perfect timing, as i just started learning about multiplexing at TAFE.

Pete said...

Neb question: Could a 555 chip be used as an alternative to the 40106 as the square wave generator?

Pete said...

I'll answer my own question months later: Why, yes, any chip that can provide a clock source can be used!

A variation of this generator is in my Lunetta :).