I need some help designing a circuit; I am new to designs and hope someone can help me out. I need a a circuit with multiple color leds or RGB led. When voltage is applied to the circuit I would like it to turn a random color for about ½ second and stay off till voltage is off and turned on again. Would this be a difficult to do, I am just starting to understand electronics. Thank you in advance.

 

Are we allowed to have continuous power & applied V just as a control signal ?
My favorite random circuit is the fast & slow clocks controlling a 4017 or 4022. I'll throw in an example, " Firefly in a Bottle ". Is LED common cathode or common anode ? How bright does LED need to be ? 4017 can drive 10 mA @ 6 V. Basic change would be to reset U3 from pin 10 & change U1 to a one shot.