[Dave] spiced up his new 2012 Nissan Juke with a little tail-light amendment. You can see that outlining the rim of the light enclosure is a series of dots. This is an LED strip that he added to augment the brake lights. It’s glued in place, and features side emitting LEDs so that the light will be focused behind the car.
To control the strip he’s using an ATtiny85 microcontroller. It’s the chip on the right, and an optoisolator next to it protects it from the 12V vehicle power which drives the strip (via a MOSFET), and acts as a trigger when the brake pedal is pressed. He wrote a few effects into the firmware. When the lights are turned on, the strip fades up to 75% over about eight seconds. When the brake pedal is pressed they go to 100%. Check out the video after the break (it seems a little weird to us, as the video runs 18 seconds but the audio keeps going… YMMV).
We’ve seen a couple of tail light concepts that flash the brake lights when you stomp on the pedal. Unfortunately the Juke (and all other cars as far as we know) don’t have functionality built-in to sense when you’ve really given the brake a sudden jolt. It makes us wonder if this info could be gleaned from the CANbus?