IR Multi-Position Switch

This multi-position switch is operated by the IR transmitter with HT12R described elsewhere in the issue.The signal transmitted by the transmitter enters the circuit through infrared detector IC4. At the output the demodulated signal is available, that via R2 and T1 is routed to the input of IC1 (decoder type HT12D). Like the encoder IC, this IC has already been described in Elektor Electronics on multiple occasions and we will therefore not describe it again here. On the PCB the address lines of IC1 are by default connected with a thin trace to ground. The default address is therefore zero. By cutting the trace with a sharp knife the corresponding address input can be made logic high.This change of address is only necessary if multiple transmitters are active in the same house.

Resistors:
R1 = 47Ohm 
R2,R3,R6 = 100kOhm 
R4 = 51kOhm 1
R5 = 1kOhm 5
R7-10 = 10kOhm 
Capacitors:
C1 = 220µ F 16V radial
C2 = 100nF
C3 = 47µ F 10V radial
C4 = 1µ F 10V radial
Semiconductors:
D1,D2,D3 = 1N4148
D4 = LED, red, high-efficiency
T1 = BC557
T2,T2 = BC547B
IC1 = HT12D (Holtek)
IC2 = 78L05
IC3 = 4017
IC4 = SFH506-40 or equivalent
Miscellaneous:
Re1,Re2 = 12-V relay, e.g., Siemens V23057-B0002-A101
K1,K2 = 2-way PCB terminal block, lead pitch 7.5mm
PCB, available from The PCBShop