555Timer. - Here is Circuit and Project Crazy Multicolor Flashing LED Globe using LM555. 555IC (IC1-LM555) is wired as a monostable multivibrator (MMV) working on regulated DC5V supply. RC components R2(1K) and C2 (100uF) sets the monotime period. At the front end of the circuit, one single-color flashing LED (LED1-5mm Red) is connected across the power rail through a current limiting resistor (R1-1K). The pulse output available from this LED is directly fed to the trigger input (pin 2) of the 555 IC. The control voltage is driven to the control voltage terminal (pin 5) of IC1 through a resistor (R4-1K). For normal use, the control voltage can be generated from a 10K multi-turn potentiometer (P1-10K) as shown in the circuit diagram. Actually, any kind of DC voltage level generator can be used to control this circuit. It could come from a photoresistor voltage divider, sound to voltage converter,from a microcontroller,etc etc. The IC1 output (from pin 3) is then extended to two 5mm multi-color flashing LEDs (LED2&LED3) through a single current limiting resistor (R3-47R).