Inspired by a question by @benniii here’s a nice custom unit that implements a slope detector, it’s not perfect but it’s pretty darn close!
cv1 == your incoming signal (S) that you want to detect a change on
cv2 == an external clock - this could be the output of another channel on your ER-301 - it needs to be just into audio rate to work effectively.
Inverting the incoming clock signal on one of the channels makes the S&H Units sample the signal (S) alternately.
S&H Output (SH1) > Mixer channel 1
S&H Output (SH2) > Inverter > Mixer channel 2
This cancels the incoming signal out except where there is a change in pitch, i.e. the alternating S&H triggers allow for a small time difference and therefore a signal output when the difference is there.
A VCA boosts the signal a bit, and then an Envelope Follower acts as a signal rectifier. Without this some of the output signals (when changing from a higher to a lower voltage) are negative and won’t act as a trigger.
Place the Slope Detector in the trigger of a Sample Player Unit to trigger a sample whenever a pitch change is detected. You could use the sample player to output a well formed trigger, gate or audio.
slope-detector.lua.zip (1.3 KB)