Debouncing Tactile Swicthes

1

Hi guys,

I’m fiddling a bit with a shift register circuit that I eventually will turn into another drum sequencer unit.

on the breadboard, the tactile switches are sending more that 1 trigger. I think they need some debouncing ro prevent that and the internet is full of different circuits to do so. I thought why not ask here on the forum. as always many thanks for your advice/help

2

Simplest option is to through a cap at it, typically a few hundred nano farads between the switch output and ground. I’ve seen some people complain that certain kinds of switches are worse than others, the red panel mount push buttons in particular.

3

Why dont you use a debounce library to handle it, just put a time for the debounce of 50mS, plenty of helpful libs out there, ones even called bounce

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4

Hi, im not using any Arduino, its just full analog with push buttons. No libs needed😁

I could however skip the whole thing and build Moritz Klein’s latest project instead. The way he explains it its just beyond belief. Even people with small knowledge (at least you’re able to read schematics and component symbols), but other than that, his video’s are awesome.

He starts with something small that could already work out for some…

If you go to Erica Synths, you can download the manual which includes the complete schematics (almost at the end of the document). The first schematic you see at one of the firsr pages is just a simple sketch.

Thanks and credits to @moritzklein that he shares that info for the DIY’ers

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5

Well you should be using an Arduino.

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6

Happy cake day @craigyb

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7

The belt and braces approach to debouncing requires using an RC (Resistor-Capacitor) circuit coupled with a Schmitt trigger or an inverter with hysteresis.

  • RC Circuit: Connect a resistor in series with the switch and a capacitor in parallel with the switch output to ground. The capacitor charges slowly when the switch is opened and discharges slowly when closed, smoothing the fast “bounces” into a slower voltage transition.
  • Schmitt Trigger/Hysteresis: Feed the smoothed analog voltage into a Schmitt trigger (or a logic gate with hysteresis, like a CMOS inverter) to convert the slow, smooth transition back into a clean, sharp digital signal. The hysteresis ensures that the output only changes state once the voltage is well past the threshold in one direction and then well past the threshold in the other, ignoring any minor, residual noise during the transition.

Crack on!

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8

Hi Farabide

how are you doing? I hope well. May I ask a question.

A while ago I’ve builded the 4 voice 16 step drum Sequencer from @moritzklein
and im very very happy with it. Just wondered if I could make a small adjustment to
the trigger part. Adding steps you must press a push button sending a +12v pulse to a transistor right? when deleting steps from the sequence, I need to press another push button that is connected to +12v, but for this I also need to press the trigger push button.

schematic is here

1 voice trigger schematic
1 voice trigger schematic841×594 60.5 KB

Want I Like to achieve is to have both push buttons from adding and removing working separately. Im just thinking how to do that so I thought maybe removing the VT4 transistor’s Collector from the trigger button and connect it directly to +12V.
Then when deleting steps, I only need to press the delete push button.

should this work? or what are your thoughts? thanks and have a nice day

adding and removing steps independently
adding and removing steps independently612×620 42.6 KB

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Hi there, this looks ok to me. I’d mock it up and give it a go. Sorry, stuck abed today. I’ll have a proper dive when I’m able.

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