For the upcoming Maker Faire the Hip Monster’s sisters team wanted a challenge. Something that required precision and also aligned well with our theme of education and steampunk artistry. What they choose to do was a true mechanical mind, a computer built with gears, the Leibniz Calculator.

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This proved to be our hardest project to date. While videos online had it look simple the precision proved difficult. We first designed a rig composed of separate segments of wood so we could explore different layouts for the gears and rods quickly. Arguable the most critical part, the step drum (the wheel like gear) was completed by the sister team in a few hours which gave us false hope the whole project would be easy.

The step drum shown above is in the center of the device. It was made from a circular piece of wood with nine evenly spaced holes along its edge. In each hole we put screws of different lengths that could be adjusted with bolts to “tune” the device on the fly. At first, we thought this would be a temporary solution but in the end we did not modify it. The device proved to be finicky and our step drum’s ability to be tuned was essential to get it to work.

Over months of trial and error and rewatching youtube videos endlessly we finally had the Ah-Ha! moment. The rig stayed in the exact same position on our workbench as a parade of other projects were started then finished as it rested, in complete. Then everything just clicked, one sister released that we were thinking two dimensional when the problem was in the third dimension. The the other sister fixed the rig and then the Leibniz Calculator worked like a charm.

Here is the final design with some added steampunk flourishes. See it in person at this year Bay Area Maker’s Faire. This project only succeed by everyone working together, listening to everyone’s ideas and refusing to get frustrated. In the end it feel more like a piece of art than calculator.

The above video shows the user adding. You use the Leibniz Calculator by first positioning the step drum to the value you want to add, subtract or multiply. Then you rotate the drum. As it spins it engages the counting gear which keeps track of the current value of the computation. The key is, since the step drums spokes are of different lengths when the drum is rotated the counting gear only is turned based on the length of the spokes. You add by rotating the drum clockwise, subtract by counter clockwise and multiply by doing a full rotating the number of time you want to multiply a value by.  For example, if you want to multiply 5 by 4 you set the step drum to 5 and rotate it 4 times.

Above you see the tens dial to the left, showing 2 which is twenty (5X4).

 

Happy Creating!