Introduction: Touch Switch

The Switch which basically detects the touch & accordingly turns ON & OFF.

Step 1: Parts

For Touch Switch we need 4 Parts as listed:-

1) IRFZ44 (40..any IRFZ Series Mosfet) it is a Special type of MOSFET which holds its o/p.

2) Touch Plate.

3) Resistor of 470 ohm.

4) LED.

Apart from this you also need a general purpose printed circuit board, battery cap & male-female pins.

You can Buy DIY Kit for this project as well as Parts from HERE !

Step 2: Circuit Diagram

  • Here S1 and S2 indicates the touch. S1 for switching ON & S2 for switching OFF.

Step 3: Making Touch Plate

  • Take the strip of the touch plate shown in step 2. Cut the plate such a way that 3 strips come under it.
  • Now take a strip of 3 male pins & solder as shown in figure.

Step 4: Soldering Switch

  • The source of the MOSFET is given directly 9v dc.
  • Gate is soldered with 2nd female pin (middle one).
  • The drain is soldered with 470 ohm resistor whose other end is given to the LED & the other terminal of the LED is grounded.
  • Two other female pins the left most & right most is given 9v & other one is grounded.
  • Now all the vcc & ground are taken at two female pins where we need to connect the battery.
  • Now when you put your finger between the 9v & gate the LED turns ON. And when you touch ground & gate together it turns OFF.

Step 5: Applications

The Touch switch has infinitely many applications some of which are listed below:-

  1. It can be used as touch sensor.
  2. Anywhere at the place of regular switch.(Only for low voltage applications)

Comments

author
gm280 (author)2016-04-27

I see a few folks are asking about using 120vac capabilities with this circuit. If I were going to do that, I would incorporate an Opto-Isolator so that there is zero issues with the 120vac getting to the touch circuitry. Just a safer way to isolate things and my opinion.

author
Sy333 (author)2016-04-23

do i need to use a risistor ?

author
Geet Patel made it! (author)2015-07-28

Here is the PCB version of the touch switch.

temp_293646529.jpgtemp_-273207346.jpg
author
BeachsideHank (author)2015-05-19

Easy, simple circuit, clear description and images. I assume it can switch higher voltage/ current if a relay is used?

Thanks for sharing.

author
3of5 (author)BeachsideHank2015-05-21

I was just going to ask this, It would be nice for projects. Just remember to use a relay made for handling 9 volts. The tiny 120volt ones I find laying around would work nicely as I used to make morse code practice units with them. and when replacing the LED with a relay, don't forget to take the 470 ohm resistor out.

author

Yes if relay is used with this circuit it can be used for higher voltage application.

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