Cosplay Lightsabers are basically glorified touch-lights for the longest time until the advent of LED strips. These LEDs, also known as Neopixel are sold by Adafruit. It does not take too long for them to be mass produced & become much cheaper over time. One can find decent LED strips from eBay & many other online shops. It’s so popular that even the hot favorite entry level soundcard Nano Biscotte V4 supports LED strips. The NBv4 manual recommends the use of mini DIN or XLR connectors. These connectors can be hard to integrate depending on the design of the hilt. So some genius came out with this:
This is a good design that can handle dueling. The flip side offers soldering pads to connect the respective wirings to the LED strips. I suspect these connectors won’t come cheap & it got me thinking, what if we can make something similar to the left connector with cheap commodity parts?
Neodymium Magnets
I had fetish for strong magnets even before I became an Apple fanboy. What if we could connect things together like the (older) Macbook Pro magnetic adapter?
It turns out to be feasible, as shown above. The magnetic grip is so strong that I have trouble separating them, but that also means it can withstand dueling strikes on the blade.
The Design
The most important component is the ring magnet which has an outer diameter that’s approximately the inner diameter of blade polycarbonate tube (~19mm). The basic design looks like this:
I used clear sticky tape to adjust the alignments such that all the rings are equally spaced out. The respective wiring stubs need to be soldered onto the parts before doing this alignment. I used a photo without wires for clearer illustration. The hilt side, cut from an uncut 40" blade tube, looks something like this:
Notice the thin resistor lead sticking out, that’s for the data line connected to the ring magnet. Thanks to the reminder from the helpful SaberTrio folks, there will be significant amount of current flowing through the + & - cables, so use appropriate wires. I used the magnets for connecting the data line since the current flow is significantly lower. The hilt-side connector (above) is part of the inner chassis that looks like this (below, on the left):
When fully integrated into the hilt, it looks like this:
Parts list
Ring magnets (10 pieces for USD$10.80): https. ://www.aliexpress.com/store/product/10pcs-19x5-Super-Strong-Round-Neodymium-Ring-Magnets-19mm-x-5mm-Hole-14-Rare-Earth-N50/2346014_32784099867.html
Assortment of Copper Washers (USD$8.38): https://www.aliexpress.com/store/product/120pcs-set-Assortment-Copper-Gaskets-Flat-Washers-Sealing-Ring-Set-with-Box-8-Sizes-For-Hardware/2657136_32784959069.html
Copper rivets (200 pieces for USD$3.57): https://www.aliexpress.com/store/product/UXCELL-200-Pcs-3-32-Diameter-1-8-Long-Shank-Flat-Head-Bolts-Copper-Solid-Rivets/2614007_32788271286.html
Sugru mouldable plastic: https://sugru.com. This holds everything together once the rings are aligned with the sticky tape.
Closing
This magnetic connector design is quite straight forward, both sides (hilt & blade) are essentially the same. The magnetic attraction is very strong, so glue the connectors to the respective holders (blade & hilt) such that it’s easier to disconnect the blade from the hilt.
The SaberTrio hilt that I am using has 2 screw sets, one for holding the blade & the other for LED sink tube, which is replaced with my connector. Hilts with single screw set (holding the blade to hilt) will need long enough wires such that the connectors can be pulled out of the hilt to a point where one can disconnect (eg. laterally) the blade from the hilt.
Time for me to work on the blade!
