What is the WERKSTATT?
The Werkstatt was designed by Moog Engineers for Moogfest 2014. The Moogfest Engineer Package
included two 3 hour workshops were you built a Werkstatt and then was shown how it works and how it could be modified.
Description of the Werstatt workshops from the official Moog site
Welcome to the Moog Music Synth building workshop at Moogfest 2014. The project for this event is called
"Werkstatt" (German for Workshop or Garage). Werkstatt is an analog patchable synth featuring 1 VCO,
1 Moog Ladder VCF, a VCA, an Envelope Generator, a LFO, and a 1-octave keyboard with glide. It is a patchable
synth with CV Ins and Outs available on a column of breadboard connections. It is also designed with hackability
in mind for the intrepid analog explorer.
The workshop is devoted to building and understanding the Werkstatt and hopefully inspiring a desire to explore
the world of Moog synths and analog musical electronics.
The Werkstatt keyboard is a simple switch matrix arranged 4 by 4. A simple free running
oscillator using one of the schmitt triggers in U14 drives a couple of dividers to make a 4 bit counter. Two
bits are decoded using a 4051 8 to 1 analog switch for the columns and another decodes the other two bits
to select the row.
Note that only 13 of the 16 possible switches are used. When a switch is pressed, it connects a row and a column.
Diodes are used for isolation so that pressing two switches does not short out two of the columns. The row
multiplexor output is fed to the keyboard trigger logic. The trigger logic clocks 4 data latches that save the
value of the counter. The output from the latches is converted to an analog value using an R-2R ladder. The analog
value is scaled and buffered.
To drive the keyboard logic from an Arduino, I added wires from the output of the row multiplexor (input to thr keyboard
trigger logic). One to each of the counter outputs so the Arduino can read the counter value.Later I added a wire to the kb clock
so that the Arduino generates the clock. Originally the clock was free running.