#795 CD4011 Toggle Touch Switch

Testing a common CD4011 touch switch circuit with single on/off toggle pad.

Build

Here’s a quick demo..

Notes

This is a common touch switch circuit based on two NAND gates from a CD4011.

I’ve made a touch pad from a small piece of copper-clad circuit board, with pins for plugging into a breadboard.

In practice, the performance is quite unreliable, certainly not good enough for a real-world application.

Circuit Design

Designed with Fritzing: see ToggleTouchSwitch.fzz.

schematic

Performance

Testing on a breadboard:

bb_build

See a quick demo..

In practice, the performance is quite unreliable. It appears very dependent on ambient humidity, and how dry or moist one’s fingers are. Certainly not reliable enough for a real-world application.

Replacing the touch pads with a push-button actually works quite well. Adjusting the capacitor value could improve debouncing the switch.

bb_alt

Credits and References

CD4011 datasheet

Reference Circuit #1

https://www.talkingelectronics.com/projects/TouchSwitch/TouchSwitch-1.html