3d Printed Hand-cranked Generator

I tried to make a little hand-cranked generator to practice my CAD and 3d-printing skills and enhance my knowledge in those topics. This was my first time designing mechanical gears and with the built-in "gear-toolbox" of Fusion360, it was pretty easy.

The outcome of this project does not serve a purpose because the produced power is only enough to power a small standard LED. So it is more like a little fun project to do when you are, just like me, starting to really get into this topic.

Supplies

I mostly used stuff I had laying around, except for the axis I used, in Germany, it is called "Zylinderstift". For the 3d printed parts, I used standard PLA and in my case Galaxy Grey from Prusa.

• PLA
• 1x 8x80mm Zylinderstift/Axis
• 2x Ball bearings with 8mm diameter
• Standard LED
• Generator (low voltage, literally one of the cheapest you could get)
• 5x M2 Screws
• 4x M2 Washers
• 4x M2 Bolts
• 8x M4 Screws
• Some glue (fix the generator outlet to the main frame)

Step 1: CAD Design

I have uploaded my STL file of the whole design - feel free to make adjustments and improvements. The design is really simple and straightforward.

Step 2: 3D Printing

Here is a list of all the components that need to be 3d printed:

• Frame 1
• Frame 2
• Gear 1
• Gear 2
• Handle
• Handelhead
• 2x distance holders between frames
• Bottom cover

I used the PrusaSlicer standard profile "Draft 0.25mm" for every part and sometimes a little less infill than 20%. Some parts benefit from a raft but it really depends on how "clean" your printer is working.

Step 3: Assembly

The assembly is also pretty easy, one tricky thing was the insertion of the axis into the bearings - I had to use a hammer to get everything in place. After screwing the generator and distance holders in place it is time to put the handle head onto the handle with the last M2 screw. After this, the handle is put on the end of the axis and the cable outlet of the generator can be glued in place just like the bottom cover.

As the last step, the LED is out into the generator outlet and you can start spinning!

Step 4: Final Thoughts

The Axis/Zylinderstift and the used bearings are major overkill. In my next project, I will try to find appropriate parts.

With a few changes and a different generator, one might charge his/her phone with such a hand-cranked machine. There are several projects and builds out there that already do that - I would like to try it on my own for the sake of gaining more knowledge and learning from my mistakes.