I’ve just finished the last details on the light dimmer box I’ve been building for Hunter Cross. He’s constructing a large “geode” sculpture which is supposed to glow, and he wants the lights to pulse like a MacBook sleep light. The project has gone through a number of major design changes, so the device I’ve ended up building is rather less elegant than it might have been had I designed it to do this job from the start, but it certainly does the job it needs to do. That is, it supplies up to 30 amps at 12V DC, running a 500 Hz PWM duty cycle, and modulates the pulse ratio with a perceptually linearized sine wave.

It looks pretty.

The background light in this video doesn’t actually change; that’s just the camera compensating for the additional brightness as the light on the desk fades up.