Uploaded October 2010 | Updated September 2026, 3 weeks ago
This year for Halloween I made skulls and candles from liquid urethane plastic and custom made silicone molds. The skulls are painted, but the candles are just colored resin and solid urethane 'flames'. (Smooth On ColorMatch 325 resin for both with So-Strong red tint for the candles.)
To get them to flicker I slapped together a LED flicker circuit using an Atmel ATMega48 microcontroller. It generates twelve software PWM's to provide for a dozen uniquely flickering candles. Update rate is about 89Hz, so the only flicker is what it intentionally put there by the code.
Wiring is using ethernet cables (cheap and available in long lengths) with six candles per jack plus power. The LEDs are 'warm white' in PLCC-6 package. The candles are actually hollow and the LEDs are mounted in the tip. The plastic flame on the top diffuses the light and lets it shine through the red plastic giving the nice candle look.
This year for Halloween I made skulls and candles from liquid urethane plastic and custom made silicone molds. The skulls are painted, but the candles are just colored resin and solid urethane 'flames'. (Smooth On ColorMatch 325 resin for both with So-Strong red tint for the candles.)
To get them to flicker I slapped together a LED flicker circuit using an Atmel ATMega48 microcontroller. It generates twelve software PWM's to provide for a dozen uniquely flickering candles. Update rate is about 89Hz, so the only flicker is what it intentionally put there by the code.
Wiring is using ethernet cables (cheap and available in long lengths) with six candles per jack plus power. The LEDs are 'warm white' in PLCC-6 package. The candles are actually hollow and the LEDs are mounted in the tip. The plastic flame on the top diffuses the light and lets it shine through the red plastic giving the nice candle look.
