A tutorial by ElectronZap shows how to make a simple and cost-effective touch switch using a 555 timer chip, a few other electronic components and a breadboard.
The circuit exploits ambient noise in the environment, which is generally enough to overcome the large resistors used in the design and trigger the threshold and trigger inputs of the 555 chip, thus activating the switch.
However, the reliability of such a touch switch is questionable and could easily be affected by environmental factors such as humidity or temperature.
For these reasons, the narrator suggests using a more reliable touch switch circuit design.
These alternatives include using touch switches that measure skin resistance or specialised modules that can be easily integrated into DIY projects.
Regardless, the touch switch utilising a 555 timer is a low-cost entry-level example of how to introduce the basics of electronic circuitry to hobbyists.
