7 things to know about Easel Proto

The program card slot on the Buchla Music Easel program card is a great platform for DIY, but like anything Buchla, it’s not completely intuitive.
The program card slot has access to 45 different signals. They’re not all strictly inputs or outputs - they’re signals that you can connect to and either read or influence.
The original Music Easel Program Card - described in lots of detail in the Original Easel Manual by Allen Strange from p23 onwards - was designed to store patches. So, with a handful of resistors, you could preset sequences and fader or switch positions.
But you can do more than just save patches: build an LFO, and patch that wherever you like. Attach an Arduino and generate euclidean pulse streams. Randomise things that can’t normally be randomised. This proto board is designed for hacking, not for preset storage (although of course you can do both).
It includes space for 3 x banana jacks, 2 x switches, 3 x potentiometers (with the supporting circuitry).
If you add pin headers and rows of resistors (as shown above) it becomes a patchbay for on-the-fly rewiring and prototyping your prototypes."
This is a good introduction to the proto board: Music Easel Hacking for Beginners.