Relay Bypass With Microcontroller

All frequent questions on switching: true or not true bypass, transistor-based or mechanical.
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POTL
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Post by POTL »

Hello
I again asked the bypass question on the relay, using a microcontroller.
I see several circuits that are similar, but the microcontrollers are different
Basically it's Attiny13 / Attiny85 / Pic12F675
I'm still far from digital technologies and I want to start studying these technologies, tell me about the difference between these microcontrollers in the operation of the bypass switch.
Will there be any difference in the work or for these purposes the microcontroller model does not play a significant role?

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Post by kingmafw »

In my opinion the microcontroller is only the tool to get it done. Food for thought can be found here:

Microchip PIC:
http://www.coda-effects.com/2017/02/rel ... -code.html

ATtiny:
viewtopic.php?f=13&t=24589&hilit=pruttelherrie
it is mei sizzen net to dwaen

Johannes Harald Kingma - FWS Pedals - Germany

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POTL
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Post by POTL »

Thanks, I read, I'm wondering if there is a difference in the performance of these microcontrollers, I'm interested in making 2 modes of operation:
1) Turning on and off
2) Switching on by holding the button and turning off by releasing the button
Can both of these types of microcontrollers work equally well?
Is there a difference?

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Post by marshmellow »

Any controller can do that. It's just a matter of preference for the designer.

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Post by POTL »

marshmellow wrote:Any controller can do that. It's just a matter of preference for the designer.
thanks

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Post by POTL »

J0K3RX wrote:or, you can try these..
https://guyatoneus.com/shop/3pdt-smooth ... ro-series/
thanks, but I do not see the point of paying $ 15 per switch, it's 10 times more expensive than the usual 3pdt in china

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Post by POTL »

for this bypass, an anti-click resistor of 1 mega-ohm between the ground and the input is not needed

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Post by plush »

POTL wrote:for this bypass, an anti-click resistor of 1 mega-ohm between the ground and the input is not needed
1-10Mohm pull down resistor is used to drain signal caps and mitigate the potential differences once the pedal is turned on.

It has nothing to do with the relay/3pdt click noise which both do have.
I guess you should leave your pull down resistor in it's place.

To mitigate relay click noise (debouncing), 5-10ms of soft or hard muting (via optofet) is normally applied. Muting means that you cut your signal to ground for a period of time untill your relay contacts stop bouncing. Contact bouncing could be very noticeable in high gain circuits or delay/reverb lines. ...small signal relays are more prone to bouncing, since their contacts groups are thinner and more springy than your typical 3pdt's.

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Post by black03 »

plush wrote:
POTL wrote:for this bypass, an anti-click resistor of 1 mega-ohm between the ground and the input is not needed
1-10Mohm pull down resistor is used to drain signal caps and mitigate the potential differences once the pedal is turned on.

It has nothing to do with the relay/3pdt click noise which both do have.
I guess you should leave your pull down resistor in it's place.

To mitigate relay click noise (debouncing), 5-10ms of soft or hard muting (via optofet) is normally applied. Muting means that you cut your signal to ground for a period of time untill your relay contacts stop bouncing. Contact bouncing could be very noticeable in high gain circuits or delay/reverb lines. ...small signal relays are more prone to bouncing, since their contacts groups are thinner and more springy than your typical 3pdt's.
Even with an optofet, pop or click noise is still heard in a speaker, if you are at a high volume. After a lot of research I think there is no solution to completely eliminate the noise.

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Post by plush »

black03 wrote:
plush wrote:
POTL wrote:for this bypass, an anti-click resistor of 1 mega-ohm between the ground and the input is not needed
1-10Mohm pull down resistor is used to drain signal caps and mitigate the potential differences once the pedal is turned on.

It has nothing to do with the relay/3pdt click noise which both do have.
I guess you should leave your pull down resistor in it's place.

To mitigate relay click noise (debouncing), 5-10ms of soft or hard muting (via optofet) is normally applied. Muting means that you cut your signal to ground for a period of time untill your relay contacts stop bouncing. Contact bouncing could be very noticeable in high gain circuits or delay/reverb lines. ...small signal relays are more prone to bouncing, since their contacts groups are thinner and more springy than your typical 3pdt's.
Even with an optofet, pop or click noise is still heard in a speaker, if you are at a high volume. After a lot of research I think there is no solution to completely eliminate the noise.
If so, there is an issue with your optofet or your code.
I have no click noise in mine. I've measured it with my scope, there is a slight bump (due to fet's resistance turning on/off very fast), but it's not audible at all.

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Post by black03 »

plush wrote:
black03 wrote:
plush wrote:
POTL wrote:for this bypass, an anti-click resistor of 1 mega-ohm between the ground and the input is not needed
1-10Mohm pull down resistor is used to drain signal caps and mitigate the potential differences once the pedal is turned on.

It has nothing to do with the relay/3pdt click noise which both do have.
I guess you should leave your pull down resistor in it's place.

To mitigate relay click noise (debouncing), 5-10ms of soft or hard muting (via optofet) is normally applied. Muting means that you cut your signal to ground for a period of time untill your relay contacts stop bouncing. Contact bouncing could be very noticeable in high gain circuits or delay/reverb lines. ...small signal relays are more prone to bouncing, since their contacts groups are thinner and more springy than your typical 3pdt's.
Even with an optofet, pop or click noise is still heard in a speaker, if you are at a high volume. After a lot of research I think there is no solution to completely eliminate the noise.
If so, there is an issue with your optofet or your code.
I have no click noise in mine. I've measured it with my scope, there is a slight bump (due to fet's resistance turning on/off very fast), but it's not audible at all.
There is no code problem, I have consulted a lot and everyone determines that it is almost impossible to eliminate the noise completely. When there is loud volume, the noise will appear, I do not know how to show you an audio so you can check

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Post by Optical »

You can control ramping of the optofet to some extent using variable current control from the processor
How is the overall impression of the optofet causing a momentary muting?

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Post by black03 »

Optical wrote:You can control ramping of the optofet to some extent using variable current control from the processor
How is the overall impression of the optofet causing a momentary muting?
I understand that and it is ok, the problem is to energize the circuit the pop is still, of course much more light than a 3pdt, but all the brands of pedals have the noise, there is none that has managed to eliminate it completely. In fact, suhr uses a slightly louder switch and I understand that it makes pop lessen.
but wampler, strymon, bogner, lovepedal, catalinbread, digitech, etc etc all have noise unfortunately.

If you have the solution, please help me! I am using the coda circuit

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Post by Optical »

Are you using an optofet?
It seems to me that the pop could be reduced or eliminated by ramping the fet conductance rather than switching it from high to low a fast as it can

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Post by black03 »

Optical wrote:Are you using an optofet?
It seems to me that the pop could be reduced or eliminated by ramping the fet conductance rather than switching it from high to low a fast as it can

Yes, I use the p222A

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Post by black03 »

Optical wrote:Are you using an optofet?
It seems to me that the pop could be reduced or eliminated by ramping the fet conductance rather than switching it from high to low a fast as it can
Can you explain how that would be?

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