Droid sensors!

Hey, gang.

Recently someone over on the Astromech Builders site designed a way for your R2 to randomly move its head back and forth without outside influence. A really nice little design and a nice little plus for when you have the droid turned on, but it’s not really doing anything…

He provided two different sensor options, but as I have come to expect, MY droid won’t really work all that well with either.

One option was a 3D printed piece in the center of the dome - RIGHT where I have a non-typical (but IMHO quite clever) Qi power source for the lights in the dome itself. After a bit of searching on the 'net and some trial and error with Qi Pads, I finally found one that had internals that were small enough to fit inside the sensor ring.

But how to hold it all together…? Glowforge!

Presenting the Roam-A-Dome Qi combo sensor:

An acrylic backplate to support the two circuits coaxially. Worked like a champ.

The OTHER side is just a sticker that you apply to the inside of the dome - except there’s that pesky Qi pad in the way… Not when you’ve got a Glowforge!

Clearances are hard to manage because with the dome on the body you can’t really get inside to check them. While the Qi system was providing power properly, that sticker was still a bit too far from the sensor ring.

Not only did 1/16" acrylic provide JUST the right spacing, it also protects the Qi Pad!
So now the sensor ring is installed AROUND the Qi power system. Next step is teaching myself how to program the system and learning a little more about radio control systems so I can tie this all in without affecting the radio controls for the dome.


That’s a great solution and a very high quality build. Feel free to post as many details about this as you like, glowforge-related or not.


I’m having trouble visualizing exactly how this works. Any chance of seeing video of it in action?


You had me at Astromech…


Unfortunately, it’s INSIDE the R2’s head and there’s really no way to get a camera in there to show it… I lifted the dome slightly and took this, but it’s hard to make out any details.

I’ll try to explain - the 9 sensors on the bottom piece (red circles) each contain a light source and a photocell:

When that light shines up at the disc rotating above it, it gets absorbed by the black areas, but reflects back from the white areas, triggering the photocell.

The combination of all 9 sensors reading the pattern of black & white on the disc provides enough information for the processor to know exactly what direction the disc (and therefore Art’s head) is facing as it rotates.

I hope that helps a little?


It helps some, but now I wanna see R2’s head rotate!

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Wow! That looks complex but cool!!

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Still running manually for now (a bit more work to do!) but as requested, R2’s head moving and the display successfully tracking that movement! Woo-hoo!

(The high-pitched whine in the background is because I have some things set differently for this test. And that board obviously won’t be hanging out like that.)


Better than the original!

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Old Star Wars is best Star Wars!

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