This project is for controlling a balancing robot that I built with the Lego WeDo robot kit. Several photos are included as backgrounds. You can see a video of the robot in action here: https://vimeo.com/131129123 It consists of a balance that rotates freely, with a movable weight on each arm. One can be pushed along by hand, the other is moved by the motor via a rubber band. Once the green flag has been clicked, the robot will move its weight so that the arms balance. If you then push the freely movable weight in, that arm will tip up, but then the robot will move its weight in until balance is restored. If you then push the freely movable weight out again, that arm will tip down, but the robot will move its weight, this time outwards, until the balance is again restored. Note that their is a yellow counter-weight on the right arm, to balance the weight of the motor and mechanism on the other. The two movable weights both weigh exactly the same. It is important to position the Lego hub so that the wires don’t interfere with the balance. I found it best to place an object under it, so that it was raised up level with the centre of the balance. My original aim with this project was to create a mechanical calculator. You can do multiplication with a balance like this, by placing a certain number of weights a certain distance from the fulcrum. The distance on the other side at which you will need to place another weight to achieve balance is equal to the number of weights times their distance from the fulcrum. (So long as all weights weigh exactly the same.) This therefore provides a method of doing multiplication. I think this should be achievable with the WeDo kit, but you would either need quite a bit more Lego, to make a much longer balance, or you would need to add non-Lego parts as well. You’d also need to find a better way of moving the weight with the motor, so it could be moved over much greater distances. If you manage to make anything along these lines, please let me know.
A Komaba original.
