Originally posted on Hack a Day:
Candle flicker LEDs are a one part replacement for a real candle. They contain both a yellow LED and a control chip that modulates the light to create a candle effect. [Cpldcpu] took a deep look into reverse engineering one of these LEDs.
To analyze the circuit, which is potted into the LED itself, a shunt sense resistor was connected to the LED. By connecting this resistor to a logic analyzer, the control signal could be observed.