Sunday, June 17, 2018

Exo Sequencer for Eurorack

The Exo Sequencer (as in... exotic, external, exoplanet, exothermic...) is a sixteen step sequencer with control voltage and trigger outputs. The control voltage range is relatively small (around 3V), and is not quantised. 

The width of the module is 18HP. 

The step order is selected in a number of ways: 
• Sending a gate or trigger to the INC input will increment the sequence
• Sending a gate or trigger to the DEC input will decrement the sequence
• Sending a combination of four LOW or HIGH signals to the four inputs A0, A1, A2 and A3 will select the step as a binary address e.g. 0000 will select step 1, 0010 will select step 3, 0111 will select step 8, 1111 will select step 16 and so on
• Sending a control voltage to the STEP input will directly select the step number, where 0V is step 1 and roughly 3.3V is step 16. This control voltage can be scaled using the STEP potentiometer
These methods for selecting the step order are not mutually exclusive, and can be used in conjunction with one another. 

The length of the sequence (used for calculating when using the INC, DEC or STEP inputs) is selected via the LENGTH potentiometer and can be modulated via a control voltage input. 

The offset of the sequence (determining the starting step) is selected via the OFFSET potentiometer and can be modulated via a control voltage input. 

Circuit board layouts, schematics, code, panel files for laser cutting and a bill of materials can be found here: 

This module is also on Modular Grid
A demonstration video is coming soon. This module can be seen and heard in some of the videos in this post