Linear shake generators have been around for a while, best example is the shake to load led lamp.

I hope to scale down this principle.

I choose to use cylindrical magnets with 3mm diameter and 3mm length.

Now i was in need of a tube with 3mm inner diameter and wall as thin as possible.
Every 10th of a millimeter more between the magnets and the coils would lower the generator.

But where does one find a thin walled  tube?
Well i tryed a few things like this pneumatic tubing with the lead of a thermocouple for a coil...

This actually worked when i checked with the Multimeter in AC mode...i was geting around 0.12mV...still basically nothing but a start.

Next step was to use another even thinner wire, so i took a old broken mini drone motor and stripped it of its windings.

That allready looked a lot cleaner, but it didnt perform better.

The walls of the pneumatic tube where just to thicc.

Then it came to me, the nozzle diameter of my 3D printer is 0.4mm thats thin.

So i printed a very thin pipe in vase mode, at first i had problems with cooling but then i just slowed down the print to 10% and it worked.

That gave me some better results, but still way to little voltage to run anything usefull.

I have to get above 20mV so i could use a LTC3108 energy harvesting IC to get some usefull voltage.

Then i found out that by stacking a few coils in series i could get higher voltages, so i gave it a try (lighter for scale).

I also printed a few washers to keep 3mm distance between the coils and a few tiny distance keepers for the magnets.

This setup generates 100uA peaks in short circuit and about 10mV peaks without load.

Thats still below the 20mV DC i need to reach...but a step in the right direction.

I think i will just add more coils in series.

Another idea would be to add 2x 1:100 SMD transformator.

That would give me 1000mV peaks in theory. then i could add diodes and will be left with about 300mV pulsed DC.

Slap a condensator behind that and the LTC3108...bam done.