My kids are like a lot of kids and scared of the dark, so I thought it might be cool to make a little electromagnetic shake lantern that uses a coil, magnet along with a super capacitor, joule thief circuit and led's to provide a nice battery free light that can be charged by "shaking" it.
The order of 32 awg magnet wire came in so I wrapped a new coil, this time I also designed and added some edges to make the wrap a bit easier, this makes it more like wrapping a spool and has small holes for wire to pass through which helps to organize the wire.
I did a 22 mm section in the middle with 10 layers which equals ~800 turns.
When testing with the same generic magnet setup as before (10x 1.5mm thick x 12mm magnets) I was now able to generate ~1.5v..
Testing with 2x 10mm thick x 12m N52 rated magnets that I ordered https://jc-magnetics.com/Magnet-Cylinders/Magnet-N52-12mm-12mm-Discs, I was able to get this up to 2.5v, not exactly as much as I really wanted, but should be enough to get it working..
Built a coil to test the power generation using some 28 awg magnet wire.
After marking out ~25mm section in the middle of the 1/2" tubing I did 6 layers of 28 awg, gluing it every so often to ensure it didn't uncoil on me.
This came out to ~250-300 turns.
When testing with the magnets I was only able to generate ~.5 volts. I tried with both 5 magnets and 10 and it still roughly the same voltage output. I think I need to get more turns to get to a higher voltage.
The issue is with the 28 awg wire I am only able to go 1 or 2 more layers before I use up all of the space available for the outside 1" tubing. So I need to try switching out to a smaller gauge.
I went ahead and put in an order for some 32 awg which should give me close to 2x the turns in the same cross section.
I will also redesign the drill holder and a couple coil edges to help make the process a little easier next time. A tighter and neater coil should generate a higher voltage.
Updated and Refined the design to better fit the components. - Added a threaded top cap to allow for access to electronic components - Added a 2 piece base to allow a 9mm switched potentiometer to be used to turn the light on/off and dim. - Cleaned up the general design to make it look better.