Introducing the first Arduino based Analog-to-Digital-to-Analog Modular USB Interface
Besides the system described below (based on the ADDAC001 Brain Module) there’s also ADDAC standalone modules:
ADDAC101 .WAV Player
ADDAC200 Multiples
ADDAC201 Voltage Inverter
ADDAC302 Nchunk Control
ADDAC401 Gated Envelope Follower
An overview over the ADDAC00x System:

Available Modules
ADDAC001
Brain Module
8 Channel Digital to Analog Converter AD5668 IC with:
.16 bits resolution (0-65535)
.8 amplification knobs
.8 monitor leds
2 x 11 position switch
Assignable control knob
Reset Button
Arduino based Software with ATMEGA1280 IC
Transmit & Receive Leds
USB programmable
16HP
Eurorack format
compatible with +-12v and +-15v power supplies
This is the Brain of this set of Modules, all the other ones shown below are unable to operate without it.
This module contains the Atmega1280 IC, the FTDI232 IC for USB communication and the AD5668 IC a 16-bit Digital to Analog converter.
The outputs are true analog voltage. These are NOT PWM outputs.
This module can be connected to a computer through USB and interfaced with Max/Msp, Live, or your favorite software using OSC or MIDI
It will be shipped with a standard set of modes described here and easy updated through the Arduino software
Software instructions will be made avalable soon
For java enthusiasts an Arduino library is available to program new modes or reassign them
For C++ enthusiasts the same Arduino library will be open-source and full control enabled |
ADDAC002 – CV/Manual Inputs
6 Channel Switchable CV or Manual Input
10 bits resolution (0-1024)
6 led to visualize input
+5 to +10v attenuator
8HP
This module allows 6 CV inputs to be read by the ADDAC001 module
These can:
.be sent to the computer to read CV voltages
.act as normal CV inputs and be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
The resolution of the digital to analog converter is 10 bit so this means that the input will be converted to a value between 0 and 1024 where 0 = 0v and 1024 =10v
A switch chooses between CV or Manual input
In CV Mode the knobs are used to amplify the incoming CV voltage so that a signal that is between 0 and +5v can be amplified to 0 +10v for full analysis range
in Manual mode the knobs are used to manually set a value between 0 and 1024
A maximum of 3 of these modules can be connected to a Brain Module |
ADDAC003 – Manual Inputs
5 Channel Manual Inputs
10 bits resolution (0-1024)
4HP
This module allows 5 Manual inputs to be read by the ADDAC001 module
These can:
.be sent to the computer to read position
.be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
The resolution of the digital to analog converter is 10 bit so this means that the input will be converted to a value between 0 and 1024
A maximum of 3 of these modules can be connected to a Brain Module |
ADDAC004 – Gate Inputs
8 Channel Gate Inputs
0 – 5v/12v
4HP
This module allows 8 CV/Gate inputs to be read by the ADDAC001 module
These can:
.be sent to the computer
.act as normal Gate inputs and be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
ON / True above 2.5v
OFF / False below 2.5v
A maximum of 3 of these modules can be connected to a Brain Module |
ADDAC005 – Gate Outputs
8 Channel Gate Outputs
0 – 5v
4HP
This module allows 8 Gate outputs
ON / True = 5v
OFF / False = 0v
A maximum of 3 of these modules can be connected to a Brain Module |

ADDAC005W – Well-Tuned Gate Outputs
8 Channel Fixed Gate Outputs
8HP
This module will allow 8 Gate outputs with it’s ON voltage quantized to a “well-tuned” note
Inspired by La Monte Young’s “The Well Tuned Piano” Piece, this is an alternative gate output module quantized to 8 notes of his very particular tunning
1v per octave analog quantization between 4 and 5v
this range will allow it to keep the gate output function for logic signals
ON / True = +4v to +5v
OFF / False = 0v |
ADDAC006 – Nunchuck Input
3 Axis accelerometer
X/Y Joystick
2 buttons
4HP
comes with a nunchuck remote modified with a Mini-DIN5 connector
This module allows the connection of a Nintendo Nunchuck remote to read it’s 3 axis accelerometer, the X/Y Joystick and it’s 2 buttons
These can:
.be sent to the computer
.be used in the Nunchuck Mode to send out independent CV voltages for each of it’s readings
.be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
A maximum of 1 of these modules can be connected to a Brain Module
Picture is outdated, it turned out that the nunchuck connectors in panel mount don’t seem to exist so i’ll use Mini-DIN5 female sockets instead |
ADDAC007 – Ethernet Input
Enables Internet access
4HP
This module allows connection to a browser, hopefully will be able to read and write information to the web
Such as:
.retrieve information from server feeds, ex. weather conditions
.send and receive CV values through a server, ex. interfacing synths at distance
.operate the synth through a browser
.visualize synth operation on a browser
Only one module can be connected to a Brain Module |

ADDAC201 – Voltage Inverter
2 Channel Voltage Inverter with Offset control
8HP
Allowing negative voltage outputs from ADDAC001 outputs
This module is the first standalone one, meaning that it can be used with this system or as a standard standalone voltage inverter, it operates totally independent from the ADDAC001 brain unit
Inspired by and used under permission of Matthias Herrmann, Fonitronik’s Attenuverter |
Future Planned Modules
|
ADDAC005A – Adjustable Gate Outputs
6 Channel Adjustable Gate Outputs
6 Knobs
0 – 5v
8HP
This module will allow 6 Gate outputs with it’s ON voltage adjusted by a knob
ON / True = 0 to +5v adjustable
OFF / False = 0v |
ADDAC005Q – 4bit Quantized Output
2 independent Quantized Outputs
2 knobs for tuning
4HP
This module will allow 2 independent 16 note outputs quantized to 1 volt per octave |
ADDAC009 – Midi In / Out
2 independent Quantized Outputs
4HP
This module allows 2 independent 16 programmable note outputs quantized to 1 octave per volt |
ADDAC011 – 8 CV Outputs Expansion
8 Channel Digital to Analog Converter AD5668 IC with:
.16 bits resolution (0-65535)
.8 amplification knobs
.8 monitor leds
8HP
This module will allow 8 more independent 16 bit CV Outputs |
Special Order Custom Modules
ADDAC001N
Brain with Nunchuck
Same specs as ADDAC001 module but with Nunchuck input instead of manual knob |
|
Modules made by Schaeffer in gold faceplate with pure white engraving

The ADDAC
Introducing the first Arduino based Analog-to-Digital-to-Analog Modular USB Interface
Besides the system described below (based on the ADDAC001 Brain Module) there’s also ADDAC standalone modules:
ADDAC101 .WAV Player
ADDAC200 Multiples
ADDAC201 Voltage Inverter
ADDAC302 Nchunk Control
ADDAC401 Gated Envelope Follower
An overview over the ADDAC00x System:
Available Modules
ADDAC001
Brain Module
8 Channel Digital to Analog Converter AD5668 IC with:
.16 bits resolution (0-65535)
.8 amplification knobs
.8 monitor leds
2 x 11 position switch
Assignable control knob
Reset Button
Arduino based Software with ATMEGA1280 IC
Transmit & Receive Leds
USB programmable
16HP
Eurorack format
compatible with +-12v and +-15v power supplies
This is the Brain of this set of Modules, all the other ones shown below are unable to operate without it.
This module contains the Atmega1280 IC, the FTDI232 IC for USB communication and the AD5668 IC a 16-bit Digital to Analog converter.
The outputs are true analog voltage. These are NOT PWM outputs.
This module can be connected to a computer through USB and interfaced with Max/Msp, Live, or your favorite software using OSC or MIDI
It will be shipped with a standard set of modes described here and easy updated through the Arduino software
Software instructions will be made avalable soon
For java enthusiasts an Arduino library is available to program new modes or reassign them
For C++ enthusiasts the same Arduino library will be open-source and full control enabled
ADDAC002 – CV/Manual Inputs
6 Channel Switchable CV or Manual Input
10 bits resolution (0-1024)
6 led to visualize input
+5 to +10v attenuator
8HP
This module allows 6 CV inputs to be read by the ADDAC001 module
These can:
.be sent to the computer to read CV voltages
.act as normal CV inputs and be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
The resolution of the digital to analog converter is 10 bit so this means that the input will be converted to a value between 0 and 1024 where 0 = 0v and 1024 =10v
A switch chooses between CV or Manual input
In CV Mode the knobs are used to amplify the incoming CV voltage so that a signal that is between 0 and +5v can be amplified to 0 +10v for full analysis range
in Manual mode the knobs are used to manually set a value between 0 and 1024
A maximum of 3 of these modules can be connected to a Brain Module
ADDAC003 – Manual Inputs
5 Channel Manual Inputs
10 bits resolution (0-1024)
4HP
This module allows 5 Manual inputs to be read by the ADDAC001 module
These can:
.be sent to the computer to read position
.be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
The resolution of the digital to analog converter is 10 bit so this means that the input will be converted to a value between 0 and 1024
A maximum of 3 of these modules can be connected to a Brain Module
ADDAC004 – Gate Inputs
8 Channel Gate Inputs
0 – 5v/12v
4HP
This module allows 8 CV/Gate inputs to be read by the ADDAC001 module
These can:
.be sent to the computer
.act as normal Gate inputs and be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
ON / True above 2.5v
OFF / False below 2.5v
A maximum of 3 of these modules can be connected to a Brain Module
ADDAC005 – Gate Outputs
8 Channel Gate Outputs
0 – 5v
4HP
This module allows 8 Gate outputs
ON / True = 5v
OFF / False = 0v
A maximum of 3 of these modules can be connected to a Brain Module
ADDAC005W – Well-Tuned Gate Outputs
8 Channel Fixed Gate Outputs
8HP
This module will allow 8 Gate outputs with it’s ON voltage quantized to a “well-tuned” note
Inspired by La Monte Young’s “The Well Tuned Piano” Piece, this is an alternative gate output module quantized to 8 notes of his very particular tunning
1v per octave analog quantization between 4 and 5v
this range will allow it to keep the gate output function for logic signals
ON / True = +4v to +5v
OFF / False = 0v
ADDAC006 – Nunchuck Input
3 Axis accelerometer
X/Y Joystick
2 buttons
4HP
comes with a nunchuck remote modified with a Mini-DIN5 connector
This module allows the connection of a Nintendo Nunchuck remote to read it’s 3 axis accelerometer, the X/Y Joystick and it’s 2 buttons
These can:
.be sent to the computer
.be used in the Nunchuck Mode to send out independent CV voltages for each of it’s readings
.be assigned to change specific functions on the algorithm running in the ADDAC001 module, speed of a lfo for example
A maximum of 1 of these modules can be connected to a Brain Module
Picture is outdated, it turned out that the nunchuck connectors in panel mount don’t seem to exist so i’ll use Mini-DIN5 female sockets instead
ADDAC007 – Ethernet Input
Enables Internet access
4HP
This module allows connection to a browser, hopefully will be able to read and write information to the web
Such as:
.retrieve information from server feeds, ex. weather conditions
.send and receive CV values through a server, ex. interfacing synths at distance
.operate the synth through a browser
.visualize synth operation on a browser
Only one module can be connected to a Brain Module
ADDAC201 – Voltage Inverter
2 Channel Voltage Inverter with Offset control
8HP
Allowing negative voltage outputs from ADDAC001 outputs
This module is the first standalone one, meaning that it can be used with this system or as a standard standalone voltage inverter, it operates totally independent from the ADDAC001 brain unit
Inspired by and used under permission of Matthias Herrmann, Fonitronik’s Attenuverter
Future Planned Modules
ADDAC005A – Adjustable Gate Outputs
6 Channel Adjustable Gate Outputs
6 Knobs
0 – 5v
8HP
This module will allow 6 Gate outputs with it’s ON voltage adjusted by a knob
ON / True = 0 to +5v adjustable
OFF / False = 0v
ADDAC005Q – 4bit Quantized Output
2 independent Quantized Outputs
2 knobs for tuning
4HP
This module will allow 2 independent 16 note outputs quantized to 1 volt per octave
ADDAC009 – Midi In / Out
2 independent Quantized Outputs
4HP
This module allows 2 independent 16 programmable note outputs quantized to 1 octave per volt
ADDAC011 – 8 CV Outputs Expansion
8 Channel Digital to Analog Converter AD5668 IC with:
.16 bits resolution (0-65535)
.8 amplification knobs
.8 monitor leds
8HP
This module will allow 8 more independent 16 bit CV Outputs
Special Order Custom Modules
ADDAC001N
Brain with Nunchuck
Same specs as ADDAC001 module but with Nunchuck input instead of manual knob
Modules made by Schaeffer in gold faceplate with pure white engraving