LASER Transmitter/Receiver

Schematic Of Transmitter

Schematic Of Receiver

Parts

Part Total Qty. Description Substitutions C1, C2 2 0.1uf Ceramic Disc Capacitor C3 1 100uf 25V Electrolytic Capacitor R1 1 100K Ohm 1/4W Resistor R2 1 1M Ohm 1/4W Resistor R3 1 10K Pot Q1 1 NPN Phototransistor U1 1 741 Op Amp U2 1 LM386 Audio Amp SPKR1 1 8 Ohm Speaker T1 1 8 Ohm:2K Audio Transformer MISC 1 Wire, Board, Knob For R3, LASER Tube and Power Supply Notes In the transmitter schematic, no ballast resistor is shown because most small LASER power supplies already have one built in. Yours may differ, and a resistor may be needed. The receiver should be kept away from bright lights. You may want to put a piece of wax paper in front of Q1 to keep the LASER from swamping it. In order to get any decent amount of modulation, you may need to drive T1 with more then a watt. The circuit can be made to transmit computer data with the use of two modem chips.