AFTERGLOW is a WPC pinball machine extension board that aims at softening the hard light on/off transitions that result in replacing the original incandescent bulbs with LEDs.

The brain of the board is a Arduino nano. It samples the original lamp matrix from the WPC Power Driver Board using two parallel to serial shift registers.

The basic principle involves resampling of the original lamp matrix signals at 4kHz. This allows for PWM LED dimming with 3 bits (8 brightness steps).

The resampled signal is output via serial to parallel shift registers an driven by 16 MOSFETs.

Make sure to check the for detailed information and instructions.