What do you get when you forcibly cross-breed an ordinary pedal bike, a Raspberry Pi and a headlamp? You get a heads-down display that projects your speed onto the road in front of you at night.
This is a prototype shown off at SXSW that hooks a Raspberry Pi up via HDMI to an LED Pico projector that replaces the standard bike lamp. It's still at prototype stage, and will only run for an hour -- and obviously not at all during the day.
"Heads Down" Display for Bicycles [MAKE]