Partial to things that go bump in the night, Bill built a circuit that slowly illuminates and fades a pair of red LEDs. It consists of two op amps, one producing a slow rising and falling voltage (3 - 6V) and the other functioning as a voltage comparator. In operation, a linear 3V ramping waveform is generated at pin 1 of the LM1458 IC and buffered with an emitter follower transistor stage. Make the rate adjustable by using a 100K potentiometer in place of the 47K resistor at pin 2. Install it in a skull as a Halloween prop or if spooky things aren't your thing, use it as a fancy power indicator for a home appliance.
For Bill Bowden's complete instructions to build your own Fading Red Eyes circuit, go to
|"Fading Red Eyes" Parts List|
|Amt||Part Description||Allied Part #|
|2||Operational Amplifier LM1458||288-1090|
|1||100 ohms Resisistor||895-0465|
|1||22 muF Capacitor||852-6516|
|Additional parts required: 9V Battery|