Sphero R2-D2 Teardown

In honor of Force Friday, we teamed up with the engineers over at Sphero to bring you two exclusive teardowns of Sphero’s just-released-today Star Wars toys featuring R2-D2 and BB-9E, a brand new character featured in the upcoming movie.

As one of the most popular characters in the Star Wars universe, there’s certainly no shortage of R2-D2 products for fans and collectors: we’ve seen garbage bins, kitchen timers, bubble machines, and even this jet plane. R2-D2 toys range from static action figures to robots that drive and respond to vocal commands.

Sphero engineers, not satisfied with what’s already on the market, told us they wanted to make the most detailed and realistic R2-D2 toy ever — one that embodies all of the essential quirks we’ve come to know and love with this classic character.

 

For this teardown, we’re focusing in on 3 major features of interest:

1. Turning head - the head contains a gearbox to power rotation and 3 PCBAs to power R2-D2’s light features.

2. Retracting third leg - just like in the movies, this R2-D2 has a third leg that fully retracts inside the body when he’s standing still and extends when he’s moving about.

3. Locomotion - Sphero’s R2-D2 moves in a very realistic fashion, driving along the ground in tripod mode and also waddling side to side when standing with two legs.

For our new readers, Fictiv is a manufacturing platform for part fabrication (including 3D printing and CNC machining) and our expertise is around the mechanical side of hardware development. For teardowns, we dig into the mechanical systems and leave the electrical analysis to our EE friends.

Turning Head

  • The head consists of an outer cover with both painted and assembled decals, an inner “skull”, and a gearbox for the rotating motion.
  • The head cover and skull are held together via beefy cantilever snaps.
  • The skull and the output of the gearbox are fixed via three screws.
  • The skull holds 3 PCBAs for the numerous lights all around the head. Plenty of light walls are incorporated into the skull to prevent light bleed.

Retracting Third Leg

  • Just like in the films, Sphero’s R2-D2 has a third leg that fully retracts inside its body when R2-D2 is standing still, and extends when he’s moving about.
  • This is not a small toy by any means, but the body is pretty tight for space thanks to this feature. The battery takes up very little room in comparison.
  • The third leg extends via a cam mechanism actuated by a motor & gearbox. The same motor and gearbox is also responsible for other parts of the locomotion.
  • The third leg has no mechanism for propulsion; it’s purely for stabilization and emulation of the way R2-D2 drives in the movies. At the bottom of the leg there is a pad made of acetal, which is excellent for low-friction applications.
  • An acetal pad was selected over wheels/balls, as a larger surface contact allows it to “float” on top of carpet

Locomotion

  • R2-D2’s two side legs have 3 degrees of freedom: shoulder, ankle, and feet.
  • To drive, R2-D2’s body swings up and forward, its side-legs swing backwards at the shoulders while the feet remain flat on the ground, and the third leg drops.
  • The shoulders and ankles are ultimately powered by the same motor & gearbox as the third leg.
  • The shoulders are controlled from inside R2-D2’s body via a cam, and the shoulder joint in turn rotates the ankle with a clever four-bar mechanism inside the leg.
  • Cams, followers, and gears are made of Delrin and Hytrel to avoid the need to lubricate the mechanism. These low-friction (more expensive) materials also mitigate noise, which is important for a high-quality feel.
  • Sphero’s R2-D2 is able to waddle from side to side thanks to these mechanisms.
  • R2-D2 has tracks in both feet so it can drive on different surface types, from hardwood floors to carpets. We regret not testing it on sand before the teardown, but we can always put it back together and take it to Burning Man.
  • The gearboxes that drive the tracks are fairly isolated from the exposed tracks so hair and debris don’t get trapped inside. With any luck, V2 will have tiny vacuums on the feet.
  • Sphero’s engineers shared that the first iteration of the track was prototyped with off-the-shelf Gates timing belt, purchased on McMaster-Carr.

Main Takeaways

The animation features on this product are really realistic — they wonderfully mimic the way R2-D2 moves in the films. Sphero’s engineers mentioned that it took many cycles of prototyping and testing to achieve this result (how terrible that they had to watch the movies over and over again...).

We can also appreciate all the hard work that went into the details of this product. For example, no screws are visible as-normal, since most are hidden behind snap-fit panels and the speaker is cleverly hidden behind the front vents and coin slots, which naturally provide an outlet for sound transmission.

It’s also worth noting that many of the body details such as vents, logic displays, and ankle cylinder wedges are all separate components. It would have been easier and less expensive to mold these with the main body panels and paint on the contrasting details, but the features would not be as crisp, and the outcome would not be collectible-quality.

During the teardown, I was reminded that in the films R2-D2 is often under repair (like when Luke Skywalker found Princess Leia’s message while cleaning sand out of R2-D2’s gears). Perhaps it’s a coincidence, but Sphero’s rendition of R2-D2 really pays tribute to these scenes with its easy disassembly. We only had to do a very small amount of irreversible destruction to get the head cover off.

Big thanks to the hardware team at Sphero for giving us a first look at this great new product — brb while we try to put him back together like Luke has done so many times!

+ We’ll be posting a special article in the coming week based on an exclusive interview with the Sphero engineers behind this new product as well as the new BB-9E product, so be sure to subscribe below to get it delivered to your inbox!

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