Simple gate circuit?

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Zijnzijn Zijnzijn!
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Simple gate circuit?

Post by Zijnzijn Zijnzijn! » Sat Jun 27, 2020 5:28 pm

I've been dreaming of making a gate machine box to have some external control over modules. Specifically what I'm thinking of is having , say, 8 inputs/outputs with a simple on/off switch between them to feed sequences thru/turn off at will, but also wired up to each output a push button (arcade machine thing maybe?) that shoots out like 5 volts for as long as it's pushed down. So while the sequence is muted, you can tap some random gates/triggers in. I'm a major beginner and I feel like this is maybe a simple circuit, if anybody could point me in a good direction on where to start?

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Eloc
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Re: Simple gate circuit?

Post by Eloc » Sat Jun 27, 2020 6:08 pm

Do you just want to pass gates/triggers through it? If so it should be quite simple. If you want to pass audio and have the pushbutton gates/triggers too, then it might be a little more complex. (Well there are simple ways for both, but audio requires a bit more if you want to do it nicely)

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Zijnzijn Zijnzijn!
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Re: Simple gate circuit?

Post by Zijnzijn Zijnzijn! » Sat Jun 27, 2020 6:55 pm

Eloc wrote:
Sat Jun 27, 2020 6:08 pm
Do you just want to pass gates/triggers through it? If so it should be quite simple. If you want to pass audio and have the pushbutton gates/triggers too, then it might be a little more complex. (Well there are simple ways for both, but audio requires a bit more if you want to do it nicely)
Not really audio - the only thing that'd come thru the input would be gates/triggers. The button would, on its own, send out gates/triggers

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Re: Simple gate circuit?

Post by KSS » Sun Jun 28, 2020 12:49 am

ON-OFF-(ON) toggle switch/ middle pin is output. Wire it to a jack. Top pin is related to the toggle being pressed down, for which the (ON) means it's a momentary action. So wire this top pin to 5V or whatever trigger-gate voltage you use. Bottom pin goes to your input jack.

You can create 8V for your gate with two resistors. say 10K to 12+ and 20K to 0V,GND. take your 8 from their joined free ends.

Flatted type bat will work better than standard 'bat' toggle for momentary action, and the standard bat handle is improved with a plastic toggle cover like you see on Buchla. Don't use red, the crappy plastic material they're made of these days breaks down and splits. Blue or black or grey or yellow or green or.. is ok.

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Navs
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Re: Simple gate circuit?

Post by Navs » Sun Jun 28, 2020 3:10 am

^ :tu:

You could also look at the Doepfer DIY page for an example of a simple manual gate:

http://www.doepfer.de/DIY/a100_diy.htm

There are also some images of switch types to help you visualize the circuit.

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Re: Simple gate circuit?

Post by KSS » Sun Jun 28, 2020 6:00 am

Thanks Navs!

The idea of this module intrigues me. Add a knob to set a variable voltage out and it's quite a useful little utility.

In the tiny-is-everything Eurorack vein, four tall trimmer knobs, next to four switches with pairs of jacks In/Out between in 4HP feels like a winner.
Could see a bigger 8switch version too. Twin pairs of four gang switches so you could hit-change a few at once. Put all 2x4 switches low on the panel, and 2x4 knobs up high to give space to actuate. Better maybe as dual unit per single module. That way you could go as wide as you wanted.
From top: In,Out x2, knob x2, space, switch x2. Just mocked it up in 2HP. It works. Def gonna make a few of these. Stay tuned..

edit: since OP really wants bigger button, there can be a side panel with only two buttons -or more. Big button panel plugs into the tiny control module. Two pin HDRs simply parallel the big button to the open mom. TOGL SW position. Best of both worlds. Duco F-F to patch the two behind the panels.

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Graham Hinton
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Re: Simple gate circuit?

Post by Graham Hinton » Sun Jun 28, 2020 6:28 am

Zijnzijn Zijnzijn! wrote:
Sat Jun 27, 2020 5:28 pm
I've been dreaming of making a gate machine box to have some external control over modules. Specifically what I'm thinking of is having , say, 8 inputs/outputs with a simple on/off switch between them to feed sequences thru/turn off at will, but also wired up to each output a push button (arcade machine thing maybe?) that shoots out like 5 volts for as long as it's pushed down. So while the sequence is muted, you can tap some random gates/triggers in.
If you just want to process Gates to control AR envelopes then it's simple, if you want to process Triggers too that may be being counted then it's not. The difference is dealing with noise and contact bounce to give clean transitions. Simple envelopes hide this little nuisance.

You could do it in hardware or you could do it all in software in the smallest bottom of the range PIC. You need a comparator with hysteresis on the input Gate/Trigger and debouncing on the button and switch and then multiplex between the two. You should also consider minimum times. What happens when you change the selection just as a Gate starts? Will you let a spike glitch through or will you stretch it?

I suggest that you play with one channel with a PIC12F508 and when it is debugged repeat the device eight times or then work on expanding the software on a device with more pins.

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