10 STEP SEQUENCER
This analog sequencer was designed with the idea of cooperative play in mind. It can be used as a standalone instrument, or linked together with other sequencers running on the same clock speed.
Mark Kleback and I were working separately working on sequencers based on Nicholis Collin's schematics in his Handmade Electronic Music. We were playing music together and we wanted to figure out a way to sync up out sequencers together simply. Very similar to what MIDI does for people's instruments, but we wanted something much simplier and easier to build and implement. So we designed this new circuit to allow multiple sequencers to be tied together or run off a master clock.
The circuit is designed to have two different timing circuits, internal and external. The internal clock is a controllable 555 timer circuit. With a switch you can change to an external clock that can be anything from other 10 step sequencers or a master clock programmed through a microcontroller.
The clock pulses the CD4017 decade counter which you can control with a ten step rotary switch. The length of the sequence can vary between 1 and 10 steps. Each step is shown visually using an LED and sent through a potentiometer to vary the voltages coming out (or rather to change the note in the sequence). There is also an on off switch for each not if you want to skip notes in the sequence.
Mark and I also added a CV output jack at the ouput of the decade counter for the user to control other instruments. Like the Realistic in the video above. However if you choose not to control an external instrument, the output of the CD4017 is routed through CD4046 Phase-Lock Loop to create audible tones. The range of frequencies is dependent on a few resistor/capacitor pairing off the CD4046 which the user can change depending on their needs.
It just so happened that ITP Camp was looking for people to help teach a workshop on sequencers. Mark and I took our schematic and designed and fabricated some printed circuit boards and put together some kits for campers. We taught a two day workshop for the campers. The first day was scheduled as solder workshop to get the sequencers up and running, and the second day was a concert for all the sequencers together.
We even got a mention on the Make Blog for our sequencer kit. We still have plenty of PCBs of the sequencer. Just send me an e-mail if you want one, and I'll happily send it. You can even see the build instruction from the sequencer class HERE