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Pencil sharpener


The idea of production line lied in my head for a while. But this particular one was the second one. I built apple peal factory that was a complete fail first. I managed to fried my microprocessor and two servos. At the end it was not able to peal the apple. I gave up and decided to design another machine, particularly pencil sharpener.

I started the assembly from the pencil rotation module which was to most significant and difficult one. After many attempts I used part of the gola stuck inside a Lego piece which holds the piece safe and solid. Then I build the input and output platforms. The output one is designed to hold the pencil during the sharpening and enable it to shift. The input one then serves to fetch the pencils from the belt.

The next step was a belt and pencils buffer. In this phase, the most difficult task was to tune the pieces placement so the belt takes only one pencil in each step. Then the push mechanism for the rotation module followed. Even this part encountered many redesign attempts. The last version uses a tooth bar.

The last issue concerned the pencil removal problem from both sharpener and rotation module. The winner was a sticker placed on the rotation module. It bites in the pencil while the module is being pushed back. When the pencil is in the output position, it moves up and releases the pencil. The module then continues to the start position. Furthermore, the pencil is rotated in reverse position after it is sharp again. This frees is from the sharpener and releases the tension in the rotation part as well.

In order to finish this creation, I have also built a small truck which is used for pencils expedition. After the sharpener was built I had to create all the programming and make final tuning of the mechanics and time all the operation together. The sharpener is operated by three motors and three servos. It contains together 6 moving parts.

Pictures, schemes, videos

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Source codes

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PencilSharpener.c: main file
PencilSharpener.h: headers file

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