Light Detector Schematic Diagram
Light detector schematic diagram. This circuit detects light falling on the Photo-cell (Light Dependent Resistor) to activate the 555 and generate a tone which is sent towards the speaker. Pin 4 has to be kept less than 0.7v to make the 555 off. Any voltage higher than 0.7v will activate the circuit.
Main page of the image: Light Detector Schematic wiring schematics