9. Mar 4th-10th: More hard-to-soft transitions and new circuits#
I really want my synth to have some more interesting sounds than plain old square waves, so this week I went back to the breadboard, to build a couple of extra circuits that I hope to include
- XOR metallic sounds: Following this Hackaday tutorial, I built a breadboard circuit that takes two 40106 oscillators and mixes them into a weird chaos, using a 4017 XOR gate. And forgot to film it…
- Filtered drum sounds: Another Hackaday tutorial shows how to do filters and drums, and I think these would be a good addition! I had a go at building this one
- Sequencer: I think my project will really be complete if I have a sequencer module, but that’s a hurdle I still need to overcome - at this point it’d be a nice bonus. I didn’t end up making it this week, because it turned out that I ordered the wrong chip for it.
My plan now is to use the 40106 oscillator:
- Oscillators 1 and 2 will be pitch controlled oscillators, with at least four different touch sensors and variable resistors that can be attached. They will be able to be mixed via resistors or diodes
- Oscillators 3 and 4 will be used with a 4070 IC to make screechy weird frequency mixing sounds
- Oscillators 5 and 6 will control a very simple 4096 drum machine
Then I still need to figure out how to add high/low pass filtering and a sequencer module, if I get that far.
After considering many different options, I want to make sure that my designs are as close as possible to zero waste. This means using squares, rectangular strips of fabric, and grids with straight line slots, as much as possible. Any other shapes should be able to tessellate within a square, if that makes sense. Hexagons would be great, but they’ll result in waste fabric scraps.
Laser cutting more grids#
I cut some more grids (of different types) out of rubber fabric and two colours of fake leather. The settings I used are documented in the MAKE section of my final documentation
I need to make the grids larger! With more empty space around the edges, because I’ll need to add snaps, or other connectors, so that the modules can connect together.
Engraving circuit diagrams on the back#
I decided I’d also like to have the underside of each module show:
- Its circuit diagram
- A brief explanation of the logic gate used (if used), maybe including its truth table
(Update: I never got around to this but I still think it’s a nice idea)
I built a prototype soft amp module:
It worked ok, but I decided that the jack socket really needed to be soldered to a few pieces of wire rather than just sewn in, to make it more secure.
I also stitched a breakout for an XOR module, which looked like this:
But I didn’t get as far as actually testing it.
(Update: this module was cut because I didn’t have enough time to finish it, but it would be nice to try again in the future)
More soft potentiometers#
This week I also tested a new design for a potentiometer. The image below shows a very rough prototype. A strip of conductive fabric is placed on top of a piece of non-conductive fabric, secured at one end, and held loosely in place in the middle and other end by fabric loops. By pulling the unsecured end of the strip, you reduce the amount of conductive fabric that’s between point A and point B - it should work as a variable resistor!