Sequencer for Analog Music Synthesizers

Features:

Up to 16 steps/voltages, each with its own LED
Each step can be enabled or skipped
Two basic step timing modes:
Individually adjustable step duration mode - each step lasts 1,2,4 or 8 time units
or:
Individually adjustable step stutter mode - each step has 1,2,4 or 8 gate pulses
Gate and triggers for each step can be enabled/disabled
Moog-style S-trigger, or gate output as build options
Positive trigger pulse output also available
Selectable internal (adjustable rate) or external clock
Sequence can be triggered by external input or pushbutton switch
Sequences available: Up, Dn, Up/Dn, Random step, Random voltage
Selectable restart or stop at end of sequence
Two (equal) buffered voltage outputs, one with variable glide
Selectable output voltage range - 0 to 5.33V or 0 to 10.66V
Saved voltage values can be truncated to next lower equally-tempered value, or unconstrained
In tempered mode, voltage skips to next equally-tempered (1V/Oct) value when encoder is turned
Up to four sequences can be stored/recalled in non-volatile EEPROM
Requires single +12VDC 500 mA power supply

One goal was to make the unit less expensive and easier to build by using a microcontroller and a 14-bit DAC together with a single encoder to make adjustments. This also makes implementing new features and modes much easier, since it's software instead of hardware. There are still a lot of switches and LED's to wire up, as you can see in this picture of the underside:

This is something that I am still fine-tuning and would like to get some other people to use and comment on. I have two blank PC boards (3.8"x2.5"), identical to the one in the above photo (but blank), available for $30 each, which includes a programmed PIC chip and shipping to USA addresses. Nothing else is provided, so you would need some kind of case, a 12VDC 500 mA AC adapter, a bunch of LED's, toggle switches, pushbutton switches and 1/4" jacks.

Here are the schematics of the sequencer:

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Here is a recording made with my minimoog clone, using this sequencer. It demonstrates the stutter feature. The external control voltage is added to the keyboard voltage, so I was pressing keys to move the pitch up and down while feeding in a sequence that simply repeated.

DISCLAIMER: I take no responsibility whatsoever for the use and/or implementation thereof, or the misuse leading to damage to equipment, property, or life, caused by the above circuits.