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RGB LEDs are capable of generating a variety of colours by mixing red, green and blue colours. It is sometimes very interesting to replace single-colour LEDs and produce different colour combinations from these three basic colours using rGB LEDs. Usually, rGB LEDs have four pins—one for each colour and a common cathode.

Presented here is a simple application of rGB LEDs that produce different combinations of colours every time these are triggered by some Ir remote

R3

control. The circuit is built around the 4-ELW ELQDUy ULSSOe FrXQWeU 74HC793 (IC2), timer IC TLC555 (IC1), photo module TSOP1736 (IrX1) and some discrete components.

74HC793 (,C2) LQWeUQDOOy FrQVLVWV of four master- slave flip- flops that IrUP D GLYLGe- Ey- Wwr DQG GLYLGeby-eight sections. Each section has a separate clock input (pin 14 and pin 1) to initiate state changes of the counter rQ WKe KLJK-Wr-Orw FOrFN WUDQVLWLrQ. Outputs (Q1 through Q2) of IC3 are connected to the base of independent transistors (T1 through T3). The r, B and G terminals of the rGB LED are connected to the collector of transistors T1, T2 and T3, respectively, through 470-ohm current-limiting resistors.

As soon as the output from IC3 becomes active, it turns on the corresponding driver transistor (T1 through 73) DQG WKe FXUUeQW VWDUWV Wr IOrw through the respective LEDs inside the rGB LED. IrX1 (TSOP1736) is an integrated infrared receiver. The CMOS WLPeU FKLS 7/C 555 (,C1) KeUe LV wLUeG as a mono-stable multivibrator.

7Ke FLUFXLW FDQ Ee FrQWUrOOeG wLWK the help of an infrared remote control.