This cool device is capable of weighing a person and measuring their center-of-gravity, similar to the Wii Fit Balance Board. But this one’s 100% LEGO. The board is raised by three rack sliders from the Mercedes Arocs set, driven by Large motors through worm gears. The large motors constantly move up and down - the weight on each area is measured by the difference in speed of going up and going down. The sliders have plenty of torque - I’ve calculated that it takes a weight of 40kg (90lb) to stall just ONE of the motors. As you can imagine, the board itself has to be EXTREMELY robust to withstand a person’s weight on it. The board is able to measure weight, calculate BMI (given height of user) and play simple balance games. It also has a calibration program where you place an object of known weight on the board for it to calibrate to. Be sure to check out Additional Information for more pics, info and a video, and get ready for more amazing builds :D!