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How to make a touch sensor replicate an on/off switch - HELP!

wrongsideof40

Dec 29, 2017
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Dec 29, 2017
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Hi folks - I have a touch-sensitive switch, intended for use with Arduino, like this...

https://www.ebay.co.uk/itm/TTP223B-...742124&hash=item2a5c1681ab:g:faQAAOSwLzdWSXos

It has a three-pin connector: VCC, OUT and GND. Touching the switch momentarily switches the output from low to high. What I actually want to achieve is the effect of having an on/off switch which is normally open circuit, then closed circuit (or 0V), when closed. The power drawn by the load will be negligable (1mA approx) so no need for relay, etc.

Can anyone please suggest the simplest, solid-state way of achieving this. I'd like to continue to use the PCB, as the touch interface is just right for my needs.

Any help very much appreciated.

Thanks
 

kellys_eye

Jun 25, 2010
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Feed the output signal to the base of an NPN transistor via a 1k resistor.
Connect the emitter of the transistor to 0V and put the load in the collector circuit (one side of the load connected to the collector, the other side to the supply).
 

Minder

Apr 24, 2015
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Or the later alternative, a Fet, the 2N7000.
M.
 

wrongsideof40

Dec 29, 2017
4
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Dec 29, 2017
Messages
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Thanks folks BUT- I tried kellys_eye suggestion, and this worked, with respect to allowing power to flow to a load (gracious thanks!).

Perhaps I poorly explained what I want to do: I want an output that will ground when the touch switch is activated, and to be open circuit, when not. The appliance I am signalling to will activate when its input is grounded, if that makes sense.

I probably need to reconfigure that transistor (or FET) but I don't know how.

Thanks again
 

Minder

Apr 24, 2015
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Here is the original PDF on it, ignore the 55¢ !
M.
 

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Arouse1973

Adam
Dec 18, 2013
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Please clarify. Press the switch once and the circuit activates, press it again and it de-activates. Or press and hold the switch and the circuit activate and release the switch and the circuit de-activates?
Thanks
Adam
 

wrongsideof40

Dec 29, 2017
4
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Dec 29, 2017
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Hi. The latter: activate for as long as switch is touched (which is what it does already, although this can be reconfigured). But rather than switch the supply to the load, I want to ground the output, when activated...
 

Arouse1973

Adam
Dec 18, 2013
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So if it does it already what do you need to do?
Thanks
Adam
 
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