Hackaday Prize Entry: Internet of Fidget Spinners

We just closed out the Internet of Useful Things round of the Hackaday Prize, which means we’re neck deep in judging projects to move onto the final round this fall. Last week, everyone on Hackaday.io was busy getting their four project logs and illustrations ready for the last call in this round of the Hackaday Prize. These projects are the best of what the Internet of Things has to offer because this is the Internet of Useful things.

We’re not sure how [Matthias]’ project will rank. It’s an Internet of Things fidget spinner. Yeah, we know, but there are some interesting engineering challenges in building an Internet-connected fidget spinner.

This is a PoV fidget spinner, which means the leading edges of this tricorn spinner are bedazzled with APA102 LEDs. Persistence-of-vision toys are as old as Hackaday, and the entire idea of a fidget spinner is to spin, so this at least makes sense.

These PoV LEDs are driven by an ESP8285, or an ESP8266 with onboard Flash. This is probably the smallest wireless microcontroller you can find, an important consideration for such a small build. Power comes from a tiny LiPo, and additional peripherals include an accelerometer to measure wobble and an optical switch to measure the rotation speed.

These electronics are fairly standard, and wouldn’t look out of place in any other project in The Hackaday Prize. The trick here is mechanical. [Matthias] needs to mount a skateboard bearing to a PCB, and no one has any idea how he’s going to do that. A fidget spinner should be well-balanced, and again [Matthias] is running into a problem. Has anyone here ever done mass and density calculations on PCBs and lithium cells? Is it possible to 3D print conformal counterweights? Has science gone too far?

Will the Internet of Things PoV Fidget Spinner make it to the finals round of The Hackaday Prize? We’ll need to wait a week or so to find out. One thing is for certain, though: you’re going to see this on AliBaba before September.

23 thoughts on “Hackaday Prize Entry: Internet of Fidget Spinners

  1. Perhaps you can electroplate the outer raceway of the bearing in nickel, then copper, then chemically tin plate it to make it solderable.

    Or just use a high performance adhesive epoxy that glues fiberglass to steel…

  2. I would use some kind of solder down clip, rather than risk melting the cage inside the bearing, which on 608 bearings is usually plastic.

    For balancing, I’d use the lead tape they sell for balancing ceiling fans, just cut it to size/weight.

    1. Additional thought. A small magnet could be mounted in the “grip” part that connects to the inner race, and a hall-effect sensor on the pcb to measure the magnetic field as it whips by.

    1. However, since everyone seems to assume that I will use the PCB for structure, I will probably build two… One with the back cover and one without. Let’s see if it can be done

  3. Jb weld it on.
    For the balancing (as its a lightweight piece), run a thread of cotton through the very center of the bearing with small rigid tube to elongate the bearing structure and prevent side wobble, then work on it like a bicycle wheel, allowing it to freely rotate and find its heaviest point at the bottom.
    Bit of trial and error and you’ll have it perfectly balanced.

  4. Awesome circuit/idea, well done :)
    Just some thoughts…The central bearing could be a generator to self power the led’s. the faster you spin, the more LED’s light up or change colour etc. Maybe a super cap to build charge, could turn in to a game device.

    1. Thank you!
      I’ll keep that in mind for the next version ;) Would be great if it could be done. However, it would not spin shorter than most fidget spinners, as part of the energy is transferred to the battery.

  5. Mount coin cell on third wing(wing without bearing) for counterbalance. Use flanged bearing to support at one end and machined nylon ring on other end to press fit. Then screw the pcd to the nylon ring.

  6. He really only needs to 3D print something like a rubber grommet (i.e. Ninjaflex) to mesh the PCB to the bearing. It will help to dampen some of the vibrational forces.

  7. I made one about a month ago. 7 LEDs, ATmega328p, coin cell at each end. I have programmed a clock, RPM, count revolution, and a bunch of animations. You can set the time by spinning it. I used two IR sensors so I can detect direction. The 328p timer 2 is running off a 32kHz crystal so it runs as a RTC and the internal 8MHz for the main clock.

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