https://a360.co/3yoCRfSThis is probably my most time-consuming 3DP project yet; completely reworking the guts of my UltraSabers lightsaber to fix all the cut corners it came with, and upgrade to 18650 power source with BMS and charging circuit. Original Obsidian e-gyro controller only does sound and lighting effects and used 14500 cells in a battery holder.
First up was several iterations before I came up with a workable design for the battery pack. Ultimately I went with a split assembly as this allowed me to completely encapsulate the 18650 cells & BMS PCB. Cells are staggered to allow as much room as possible for wiring from one end of the hilt to the other.
Here I've bonded the Obsidian controller PCB to the battery pack with a blob of good ol' silly-cone RTV sealant. This is roughly how it will reside in the hilt; the space behind the pack is where the LED ballast PCB and speaker go. The space forward of it are where the power switch and emitter module go.
There's a space of aboot 50mm right in the middle which is all the space available for the switch and excess wiring to scrunch up when this is assembled. This problem is a major part of why it took several days of tinkering in my off-time to get everything figured out.
In the middle of all this came some R&D work. I wanted to replace the original ballast resistors with some CC LED driver PCBs I found online; however after multiple test scenarios, they proved not durable enough mechanically or electrically for the abuse intended. I eventually abandoned this testing after smoking a couple LED emitters and half-dozen CC driver boards. I am toying with the idea of mixing up my own 3-ch CC LED driver PCB to fit in this space; I might follow through with that if I find a chipset that actually handles the abuse under testing.
When I first got my saber, I changed the color to a deep royal purple to match my generally lawful neutral alignment; getting that requires mixing red & blue at drive current levels determined by trial/error. On top of that there is another channel for "flash on clash" functionality in the sound/light controller PCB, so I use all 3 elements in this one. As I had already done the headache work with the ballast resistors, ultimately I returned to that arrangement when the CC LED drivers proved inadequate.
Here is the ballast PCB, LED emitter module and battery pack before adding the charge circuitry; I've covered the LED wires with Kapton tape to make it act as a ribbon cable, and to add a layer of protection against pinch damage. Yes, they are made of multi-strand Cat5 cable; I use what works, and it has the right mix of flex and just enough rigidity to push back into place rather than bunch up as the parts are assembled in the hilt.
One of these days I'll get this 10W LED emitter on the left working. These require a completely different emitter housing and collimator lens; also aboot 4x as much VA power source so will take a lot more finagling, and will absolutely require a working CC driver array to fit in a usable-sized hilt. Future plans...
Component density is pretty high for a fabricobbledy project. The sub-board plugs into the controller via a short pigtail of Dupont connectors...
...and the LED channels are broken out into another row of Dupont connectors facing back towards the front of the hilt. There's a Schottky diode in there so that we don't have sparks if something shorts the charge port, and the ugly soldering is to ensure the heavy resistors are anchored to multiple vias in the perfboard so they stay put under heavy impact from mock combat.
Before you ask, yes I've repaired the potting over that inductor with a fresh layer of epoxy. It's just not really visible here.
Here I've designed and printed the speaker bracket and the charge port; they go together in layer cake fashion...
...with the charge port poking up like a smokestack.
Once I add the pommel ring, it looks a lot better. The battery, speaker and charge port layer cake required an additional 3mm clearance overall; I was able to gain that by printing up the random-looking spacer ring in the first pic. Once sealed up, the entire insides of the thing becomes a resonating chamber for the little speaker; the difference in sound is amazing once you tighten the pommel ring down. In this case, that perfboard PCB actually works in my favor.
And here's the money shot; this lightsaber has e-gyro controller with flash-on-clash, motion sound effects, fully-programmable sound library, 18650 power source with more than 2X the power density of original, and charge/BMS circuitry the original design never even thought of. As a bonus, it works perfectly with the 8.4V charger I already have for my bicycle headlight.
Printed on my CReality CR-6SE in XINGTONGZHILIAN Brand Black PLA, 0.16LH, 60mm/s, 200°C/60°C Bed, no adhesion, Supports enabled/touching buildplate, infill set manually to 1mm grid, 1.2mm wall/top/bottom thickness, with combing & bridging mode enabled and part rotated to benefit bridging; otherwise all Cura defaults. Total time: Fuck if I know... mnem
And my son is more excited aboot it than I am...