The Useless Candle
Remember the cool Usless Machine? Well now there is a Useless Candle. New idea but just as much useless fun. As soon as you light the candle the system detects that it is lit and blows it out. 🙂 “The control circuit for this project is built around a 555 timer IC. When light shines on the CdS photoresistor, the voltage at pin 2 drops below the trigger threshold. This