OVER/under

In keeping with our interest in generative modular compositions, We would like a way to programmatically introduce a sense of progression. We believe we can accomplish this with a counter module. Such a module would increment or decrement an internal counter on receipt of a related trigger. When the counter rises beyond a specified limit (or drops below zero), the module outputs triggers to indicate the associated condition.

The working name of this project is OVER/under.

• inputs

  • steps (knob)
  • steps (CV, -5 – +5V)
  • increment (trigger)
  • increment (button)
  • decrement (trigger)
  • decrement (button)
  • enable (gate)
• outputs

  • overflow (trigger)
  • underflow (trigger)
  • wrap (trigger)
  • percent/progress (CV, 0 – +5 or +10V)

The module will also have some kind of display to indicate the counter's internal state, either an LCD with boxes (think Pam's Euclidean rhythm display) or a series of multicolor LEDs.

The percent or progress CV out sends a stepped voltage based on the counter's progress to the selected step count.

A proposed pseudocode outline appears below.

init:
  length = 1
  counter = 0
  
  n = max length
  k = knob CV scale
  r = output range for percent out (+5V or +10V) 

loop:
  clear expired triggers
  read steps knob
  read stops CV (norm = 0V)
  length = k * [steps CV] + [steps knob], clamped to [1, n]
  counter = counter % length, do not emit wrap triggers
  read enable (norm = +5V)
  if enable > +2V and increment triggered:
    if ++counter >= length:
      counter = counter % length
      emit overflow trigger
      emit wrap trigger
  else if enable > +2V and decrement triggered:
    if --counter <= 0:
      counter = counter % length
      emit underflow trigger
      emit wrap trigger
  update interface
  set percent out to (counter / n) * r

This project is ideal for testing within the virtualized environment offered by VCV Rack.