I was disappointed by Star Wars: Jedi Challenges as a product, thankful I only paid clearance price for it but that also meant I couldn't demand a refund for a lackluster experience. No matter, I still got enjoyment by taking apart its Lenovo Mirage AR headset to learn how it worked. And now I will take apart the main peripheral: Rey's Lightsaber.

Production promotion proclaimed this to be a "collectible-grade" lightsaber. I have no idea what that is supposed to mean. Perhaps Disney licensing department has defined categories for their merchandise, but as far as I'm concerned, it's just marketing fluff.

Fluff aside, I will give it credit for being far more detailed than I had expected. A high-quality shiny chrome finish throughout the device gave it a much more premium look than cheap Halloween costume lightsabers made out of dull gray plastic pretending to be metal. Chrome finish aside, though, this is sadly still just plastic pretending to be metal.

This saber talks to the phone inside the Mirage AR headset via Bluetooth. (When powered on, my phone can see it as a Bluetooth device named "Rey's Saber".) FCC paperwork is required for all consumer products sold in the United States that transmit and receive data over any kind of radio frequency including Bluetooth. Such data is public record so armed with an FCC ID (O57AR7651N in this case: O57 is Lenovo, and AR7651N is the Jedi Challenges product) we can go to FCC's ID search page and see what has been filed for a product. This frequently includes photos of the product in disassembled form, a very useful guide for teardowns. Nothing like a detailed iFixit teardown guide, but we can see the major pieces and look for fastener locations. It cuts down on the fruitless hunting, especially when the fasteners are well hidden, which they were for this saber.

Thanks to the filing document "TempConfidential_Internal Photos_Rev1" PDF, I could see a fastener lined up exactly at the location of a nonfunctional button. It was held with double-sided tape and could be removed to access the Philips-head screw underneath.

Freeing that single screwed allowed the tip to slide out.

If somebody wanted to repurpose this lightsaber as a costume prop, it should be easy to replace the soft translucent white tip with something more appropriately mechanical in appearance.

That translucent white tip is illuminated by this surface mount component.

Backside of this small circuit board indicates it is a trio of LEDs in a single surface mount package, controlled by four wires: one each for green, red, and blue and a common ground.

Returning to the FCC filing PDF, I saw the base had two heat-set inserts to accommodate machine screws and the picture quickly guided me to where they were hidden underneath glued-on rubber pads.

Remove those two to release the base.

Rubber pads hid two more screws.

Removing them allowed the grip to slide off.

Things got trickier from here. Looking at filing pictures I could see a screw is hidden underneath this button, but I couldn't see a graceful way to access it.

I ended up prying against the four little claws inside the saber in order to release the button, then I could access that screw.

Then I could slide off the center ring section, exposing three final screws holding the exterior in place. Once removed the exterior could slide a fraction of a millimeter but it is not yet completely freed.

A bit of wiggling pointed to this button as the culprit. This is a functional button and that knurled surround hints at a ring I could remove, but that was an illusion. I saw little plastic pieces inside and thought I should pry them free just like I did the previous button.

That was a mistake. Prying the button free damaged both it and the socket it resided in. Now that I could look at its distorted shape, it appears to be designed to be uninstalled with a quarter-turn counterclockwise. I have no idea how I would grip this button (while installed) solidly enough to perform that quarter turn overcoming the little nub designed to resist accidental turning. Maybe a suction cup? I don't know. What I do know is that it's now too damaged to be reinstalled with a quarter turn clockwise. I had hoped to tear down this saber nondestructively in case I have an idea for repurposing it, but I have passed that point of no return. Ah well.

Setting that disappointment aside, I can look at saber internals. It is a very thinly populated board with few components.

A Nordic Semiconductor nRF52832 runs the show, built around an ARM Cortex-M4 CPU.

The black plastic backbone securely holds an electric motor with an eccentric weight on its shaft. This would be good for shaking the saber in our hands to signify battle action.

The black plastic frame also holds this piece of metal that does nothing except add heft to the saber so it feels appropriately substantial when picked up.

Given its weight, I had expected a chunky array of NiMH or even NiCad rechargeable batteries inside, but it's actually a slab of metal and this thin little lithium-polymer pouch. I would have said it was undersized to drive the tactile feedback motor but I'm no battery engineer.

Several test points are visible adjacent to the battery directly behind the microcontroller. I assume Lenovo/Disney locked down the nRF52832 so we can't flash our own firmware. Maybe a skilled ARM security researcher could find a way in via glitching the power supply for fault injection, but I don't know how to do that. The locked-down nRF52832 can be unsoldered and replaced with an unlocked chip, but such tiny BGA chips are also beyond my current skill level.

I didn't expect to find much in the way of reusable components, and I didn't. I was surprised at the robustness of the mechanical construction. I had expected to find a single screw and have it fall apart in two halves. I'm glad I found the FCC filing PDF, which made this teardown go smoother and almost nondestructively. Now for a change of pace, I'll take apart the final hardware component of Star Wars: Jedi Challenges, a simple illuminated AR beacon.