A new 4HP version of the ADSR module, based on an Arduino + DAC to generate an envelope control voltage for a VCA, VCF or whatever.
GATE IN input – when this goes high (5V), a new envelope starts
ATTACK knob – rise time 0s-11s of ramp up to initial peak 5V level
DECAY knob – fall time 0s-11s of ramp down from initial peak 5V level to SUSTAIN level
SUSTAIN knob – constant level 0V-5V which is held while GATE remains high
RELEASE knob – fall time 0s-11s of final ramp from SUSTAIN level to 0V
ENV OUT output – control voltage in range 0V-5V
LEDs next to each knob chase through the A-D-S-R sequence.
Circuit
This is exactly the same circuit as the original ADSR module – please see that page for details and Arduino software.
The circuit is split over two pieces of perfboard cut from a larger board, connected by 14-way headers and sockets at top and bottom. All components are wired point-to-point with 30 AWG kynar wire.
The first board has four Alpha 9mm vertical pots and two PJ398SM mono jack sockets which mount directly to the aluminium front panel.
The four LEDs have 8mm lengths of insulating sleeve on their legs, to match the height of the other components.
Pots, sockets and LEDs all wire directly to pins on the two 14-way sockets, connecting to the second board…
The second board has:
- two 15-way sockets for the Arduino Nano
- MCP4822 DAC
- LM358 op-amp, chosen to go all the way down to 0V with a single-rail power supply.
- 10-way boxed power connector with only +12V and 0V used, and an electrolytic capacitor chosen to fit the available space.
Because space is so tight, some of the components and wiring are located under the Arduino.
The second DAC channel and the second op-amp in the 8-pin package are not used – in previous builds these were brought out to extra PCB pins for future experiments.
ShedSynth 