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Analog LED (touch) switch - without uP

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misiacik7

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Hi,

I saw many switches that are using uP and code.

1) Is there a way how to make it analog way? I dont care if there will be 2 led if needed... One as Light source and second as recipient (sensor).

2) It should have two ouputs based on time of being "pressed".
- when i "press" the switch for less then app. 0,5s it should let short signal pass once
- when i hold it more than 0,5s after release it should let let short signal pass second time (one on by pressing and second one on releasing the switch)

Any idea?
 
Have a look at this collection..https://www.555-timer-circuits.com/

There will be something here for you...

(hint... if you get a dual 555 timer with two different functions)
 
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I'm not clear what the LED is for. If you are just trying to make a touch-switch which generates one short pulse if touched briefly and two short pulses if touched for >0.5s then you don't need an LED at all: you could do this with CMOS logic gates.

Alec
 
There are well made capacitive touch sense chips that handle static discharge and changes in temperature & humidity. After that, a 555 & some gates or a uC will let you do what you're looking for.

Cypress Semi has a line of uCs that are specifically for touch sense input / process -> output. Their stuff has a learning curve, but it's worth it. You can do functions using their products that take multiple chips otherwise. Good Hunting... <<<)))

Oh yet again... I reread OP only to realize it's sufficient vague to not know if I'm relevant....
 
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Ah....if an ordinary LED is to be used as a light sensor that's a different kettle of fish. The circuit will be quite complex, as it will be necessary to amplify the sensor signal and use modulated light to overcome the effects of background illumination and noise pickup.

Alec
 
to 4poyros:

you are right... I am looking for panel (touch) switch. Something like "Capacitance touch switch", but done by 2 LEDs. One which will be still on, and the second one used as sensor. The sensor will sense the light reflected from finger, which will be close enough (pressed switch). But I am not familiar with programming uC, therefor I want it "analog" way.
 
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