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Momentary Touch sensor
Moderators: adafruit_support_bill, adafruit

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Momentary Touch sensor

by iLLaFenT on Tue Aug 04, 2020 2:34 am

Hi , first post on here. I have been searching around but need help. So I have the Momentary Capacitive touch sensor and need help wiring it. I will be wiring it to a guitar effect pedal. I will replaced the 3dpt foot switch with the sensor. How do I go about hooking this up? Do I wire the output of the sensor to the input of the guitar PCB circuit?
I will post pictures when I strip down the PCB
thanks

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Re: Momentary Touch sensor

by adafruit_support_bill on Tue Aug 04, 2020 5:37 am

The output of the capacitive touch switch is a logic-level signal. LOW by default and HIGH when touched. Depending on the design of the effect circuit, you may need some additional circuitry to interface with it.

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Re: Momentary Touch sensor

by iLLaFenT on Tue Aug 04, 2020 11:40 am

What kinda of additional stuff would i need?
IMG_9175_500pix.jpg
IMG_9175_500pix.jpg (173 KiB) Viewed 46 times

IMG_9171_500pix.jpg
IMG_9171_500pix.jpg (226.25 KiB) Viewed 46 times

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Re: Momentary Touch sensor

by adafruit_support_bill on Tue Aug 04, 2020 12:15 pm

Without a schematic, it is impossible to say for sure. But my guess is that your 3pdt switch is switching analog signals. You could replace the switch with a 3pdt relay and a transistor circuit controlled by the touch switch to drive the coil. Unfortunately, most of the 3pdt relays are designed for switching power, not signals. So they may be a bit bulky and power hungry for your application.

https://www.te.com/commerce/DocumentDel ... ng=English

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Re: Momentary Touch sensor

by iLLaFenT on Tue Aug 04, 2020 1:31 pm

so something like this? Relay bypass PCB

https://buildyourownclone.com/products/ ... pass-board

Image

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Re: Momentary Touch sensor

by adafruit_support_bill on Tue Aug 04, 2020 3:23 pm

Something like that. Looks like that one has just a DPDT relay in it. Not sure what the third pole of your 3pdt switch does, but that bypass will only switch 2 poles.

It also looks like that bypass circuit is set up for a 'normally high' input. So the momentary cap-touch switch would not be ideal. You could use one channel of this board which has 'normally low' outputs: https://www.adafruit.com/product/1362

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Re: Momentary Touch sensor

by iLLaFenT on Tue Aug 04, 2020 8:08 pm

I was mistaken the switch is a 2dpt since there are only 6 terminals.
this is where is am. Hopefully i can use the really and then wire the touch sensor to that.
What is the best touch sensor material to use? I need it to be fairly study since i will be touching it a lot.
I have a guitar with an XY kaos pad on it and want that similar instant response with a decent area.
IMG_9181_400pix.jpg
IMG_9181_400pix.jpg (248.82 KiB) Viewed 38 times

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Re: Momentary Touch sensor

by adafruit_support_bill on Tue Aug 04, 2020 8:20 pm

Any conductive material will work. Copper foil behind some 3mm acrylic generally works well.
https://www.adafruit.com/product/1127
https://www.adafruit.com/product/4607
Or a nice polished metal plate if that works better for the aesthetics of the guitar.

Keep in mind that the sensitivity increases with the surface area of the touch pad. If it gets too big, it can get a bit unstable. Probably best to experiment with some foil first to find a workable configuration.

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Re: Momentary Touch sensor

by iLLaFenT on Tue Aug 04, 2020 11:41 pm

Thanks for all the help! I'm a noob.

So whats the difference between low and high mode? i will order that chip you linked.

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Re: Momentary Touch sensor

by adafruit_support_bill on Wed Aug 05, 2020 5:48 am

So whats the difference between low and high mode? i will order that chip you linked.

For that chip, all the outputs are normally at 5v (HIGH). When you touch the pad attached to one of the input channels, the corresponding output goes to 0v (LOW).

Note that this device is designed for 1.8v to 5.5v operation. I know a lot of guitar circuitry is designed to be powered with 9v. It looks like that bypass board has either a 3v or 5v voltage regulator on it, so you may need to 'borrow' some power from that board for the touch sensor.

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Re: Momentary Touch sensor

by iLLaFenT on Thu Aug 13, 2020 7:08 pm

so I'm thinking of using this relay since its setup to be momentary.



Image

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Re: Momentary Touch sensor

by iLLaFenT on Mon Aug 31, 2020 9:47 pm

slight delay, i was waiting for the effect kit to restock. back in design mode
how could i hook this touchpad up?
https://uk.rs-online.com/web/p/touch-switches/8232258/

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Re: Momentary Touch sensor

by adafruit_support_bill on Tue Sep 01, 2020 5:57 am

Not familiar with that product. The seller should be able to advise you on how to connect that up.

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Re: Momentary Touch sensor

by iLLaFenT on Tue Sep 08, 2020 11:31 pm

So i have been trying to figure this out. I am also waiting on responses from the manufacturers.

pedal project1_100pix.jpg
pedal project1_100pix.jpg (329.81 KiB) Viewed 6 times

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Please be positive and constructive with your questions and comments.