Automatic transmissions were a breakthrough for cars more than half a century ago. Now we have an automatic gear shifter for a bicycle. Colorado State University engineering students Ben Johnke, Bill Engelking, and Matthew Stout created a bike that shifts gears by itself based on several inputs: rear wheel speed, pedaling direction, and initial chain position.

The students used the factory derailleur cable system, but they added high-torque servo motors instead of hand-turned levers. The bike uses four PIC microcontrollers to process the inputs, control the shifting, and display data to the user.

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The Colorado State University engineering students who created the self-shifting smart bike (left to right): Ben Johnke, Bill Engelking, and Matthew Stout.

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