Negistor Experiment

I was looking around the internets the other day and stumbled across this little gem. 100 Oscillators! Zoiks.   As it turns out, I had already been toying with building a drone synth of some kind. Just was not sure what I wanted.

I had bought some Arduino mini pros and a FTDI programmer for stupid cheap.  They work fine, but the inspiration was low this sounded more interesting. From the sound of the video, it was an elusive circuit I had played with years ago.

The Negistor Oscillator!

The first time I had seen it was on a website that belonged to moosapotmus. The circuit seems simple enough.

Since I was building mostly stompboxes, I was striving for a 9v supply.  This was downright impossible to get to work except for a handful of 2n2222a npns that were in metal cans.

Eh…moved on.

The circuit on Look Mum No Computer is a little different.  There is an LED between the collector and ground.

Giving it a second shot, it was just as messed up.  Bringing up the supply voltage works to a degree.  I seemed to get similar results as here.  One type of 2N2222 would work while another 2n3904 might not really work at all. Sometimes they would only oscillate over a small range.

I picked out 5 transistors that seemed to play well enough together to piece together this.

ATTiny85 Midi controlled synth

The last time I tried to program the ATTiny85  to be controlled by midi, I did not have a lot of luck.  First thing is that apparently you need to have a bit of precision on you clock.  Internal clock speeds for these chips have low precision.

Also, midi is a standard…but a loose one at best it seems.  There are lots of ways to send the same note. The midi controller I had did not send things like I expected it to. And yet it was compliant to the spec. Still, this is hopeful.