This is a very simple touch sensor switch that is build with the 555 timer IC. ... Touch Sensor Switch Circuit with 555 timer. February 27, 2013 by P. Marian ... circuit diagrams and crazy projects ...

When the infrared light beam is interrupted, the oscillator built around the 555 is enabled and starts to produce a warning tone. Finally, the test values indicated in the infrared barrier alarm ...

Here’s your useful and beautiful circuit for the day — [New Pew]’s vibration sensor takes manual control of the flip-flop inside a 555 timer and lights an LED in response.Use it to detect ...