Flip switch using triggers / pulses over time? ( rate counter? pitch comparator?)

hey, all.

i’m trying to make a geiger counter effect in VCV. specifically, i’m trying to make a geiger counter with an alarm that goes off when the rate of “blips” (the “radiation”) reaches a certain level.

here’s what i’ve got so far to generate the blips:

VCO outputting pulses > bernoulli gate > sampler (“blip” sound) > output

when i increase the LFO speed, more pulses get through the bernoulli gates. it sounds pretty convincing!

but for the life of me, i can’t figure out how to go about making an alarm that goes off when the rate reaches a certain speed. i have the alarm sound – it’s just a steady beeping tone. but i’m not sure how to turn it on and off.

i’m still pretty new to modular in general, so there might be a name for the exact thing i’m looking for and i just don’t know it yet. but basically, i need a module that will count how many pulses come out from the bernoulli gate, and if the rate exceeds a certain amount within a certain amount of time, it sends a signal to a switch to turn the alarm on. and when the pulses fall below a certain amount within a certain amount of time, it sends a signal to turn the alarm off.

i’ve tried using slew limiters to smear the triggers into a signal, but it’s pretty jankety and doesn’t work across the whole sweep of possible rates. i’ve also tried taking the output of the VCO itself, rather than the bernoulli-fied triggers and running it through a pitch tracker, then running the pitch tracker into a comparator. again, it’s pretty jankety, and isn’t relying on the actual “blips”, which diminishes the effect somewhat.

been tinkering with this for a couple of hours now, so any and all help is appreciated!

Geiger_counter.vcv (10.4 KB)

I used the rising edge of the gates from the bernoulli as input to a slew limiter. rise time is fast and fall time slower, it takes a bit of adjusting to get it right. the comparator is set to 4.9 (out of 5V max ) - it triggers an adsr for the alarm oscillator (the right FM-OP)

This was what I could come up with.


This is my approach. Since you want to measure triggers over time, you need a counter (Event Timer) and an additional steady clock (1.st LFO1). The Event Timer will only release an End-Trigger, when it has counted down to zero, and that only happens when there were enough clock-triggers before the timer-clock resets the event timer. This works only on the accelerating part, but you could use a gate-delay to set the length of the end-gate and connect that to a momentary switch.


dang, you guys work fast! excellent methods, and many thanks. :grin:

right before i came back to check on replies, i implemented what i’m now calling the “caveman” solution:

for some reason, it didn’t occur to me to use a constant voltage to control the VCO while sending it to the comparator at the same time. :tipping_hand_man:

either way, it’s not perfect, and i like both your implementations more for getting an alarm that functions based on the number of pulses coming through. you know, like an actual alarm! and i just know that’s gonna be extremely useful in future patches of all kinds.

big thanks to you both for solving a mystery that kept me up tinkering half the night. :slightly_smiling_face:

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