Above is the transmitter and the image below is the receiver:


To adjust the circuit, hold down S1 while pointing LED1 at the receiver. Adjust R6 until you hear the relay click.
You can increase range by using a high output LED for LED1.
Bright light will stop the receiver from responding to the transmitter.

Resistor [R1] : 11K, ¼W
Resistor [R2] : 1M, ¼W
Resistor [R3] : 1K, ¼W
Resistor [R4, R5] : 100K, ¼W
Potentiometer [R6] : 50K
Capacitor [C1, C2] : 0.01uF, 16V
Capacitor [C3] : 100pF, 16V
Capacitor [C4] : 0.047uF, 16V
Capacitor [C5] : 0.1uF, 16V
Capacitor [C6] : 3.3uF, 16V
Capacitor [C7] : 1.5uF, 16V
Transistor [Q1] : 2N2222
Transistor [Q2] : 2N2907
Transistor [Q3] : NPN Phototransistor
Diode [D1] : 1N914
IC [IC1] : LM308
IC [IC2] : 567
LED [LED1] : Infrared LED
Relay : 6V Relay
Switch [S1] : SPST Push Button
Battery [B1] : 3V