Finding that his recently purchased LED Christmas lights defaulted to an annoying blinking pattern that ... alternating 500 Hz square waves with a 555 timer and a 74HC74D dual flip-flop.

The illumination LED lights up or blinks in response to remote control operations and lights up in different colours according to the status of the TV. Yes, but it's not advisable. Without the LED ...

It’s a freeform circuit that synthesizes sound using 555 timers ... in the form of a RGB LED. One with a self-contained circuit to cycle through various colors and blinking patterns.