Ever since buying a couple of modules, I’ve fallen in love with analogue modular synths, they are addictive beyond belief and I’ve yet to find anything as engrossing as standing in front of it twiddling knobs for no apparent reason generating all sorts of swirling modulating filtering noise. I can loose hours very easily. As always though I’m never satisfied and I want to tinker. One of my projects I’m most actively researching is the idea of an arduino based Step Sequencer.

There are a million threads online with people desperately trying to get their trusty arduino’s to generate control voltage. The problem you have is that the arduino doesn’t live in a real analog world, it’s all about the digital. The only smooth it can do is PWM, and even then it’s really not go lovely to listen to. There are huge threads about people applying filtering, or faking analog with complex software, or powering 8bit, 12bit 16bit DAC and the huge amount of arduino sketches needs to handle them, and to be honest it’s totally terrifying for something that is as easy as turning a pot. So I decided to take a different approach. (if you really want to make music with an arduino, go see midivox, I just got a couple and they kick ass)

I want to keep the analog signal pure, and only handle the step side of the equation using the arduino. So the initial idea would be 8 pots, 1 thru 8. a single CV in, a single CV out. The arduino would be hooked up, so that when messages are sent down the USB connection, current passes thru 1 specific pot and comes out the other side.

So I can set up my “notes” with the analog pots, and then just trigger which one, when, how long and what order they get “played”.

After this initial prototype, I’d shoot higher and aim for 3 or 4 rows of 8 each with their own dedicated CV in and out, and gate outs, and tempo outs, and LED’s flashing, and a front accessible USB port, and way to store sequences on a memory chip that is slotted into the front and sequences chosen using nothing but the power of the mind, etc etc etc.

It seemed like a no brainer DIY project, that maybe one day would lead to PCB’s and kits and open source and all that stuff I aspire to do.

Due to my limited real knowledge thought I’m already overflowing with questions. First of which is how I do this, and what’s the best “switching” mechanism should I use. Should I use relays, optoisolators, Voltage controlled resistors, transistors or just good old plain Jane relays. I have some open question on the arduino forums so hopefully I’ll get some validation for my madness. Any suggestions feel free to jump in.