Ardubracelet Lets you Play Tetris on your Wrist!

Making your own Tetris game is almost a rite of passage for hackers — [Kevin] has stepped up the game a little by making this awesome-flexible-triple-displayed-Tetris-watch dubbed the Ardubracelet.

At the recent Maker Faire SF our head editor [Mike] got a chance to meet with [Kevin] from Arduboy who told us about some of his upcoming projects — this wearable was one of them!

It features three super bright OLED screens on a flexible circuit board with conductive touch buttons to continue with the minimalist design. Instead of a wrist strap he’s actually made the ends magnetic to hold it in place — did we mention the battery also lasts for over 10 hours?

At the heart of the flexible circuit board is an Atmega328p, which is the same chip used in the Arduboy (a credit card sized GameBoy). This is just the first prototype but he’s planning on making it even better in the future complete with Bluetooth and some 3D printed parts to make it look a bit nicer.

15 thoughts on “Ardubracelet Lets you Play Tetris on your Wrist!

  1. Very cool idea.

    However, I don’t think this is a flexible circuit board” per se. I could be wrong, but this looks like several rigid PCBs jumpered and held together with kapton tape. I was hoping to learn of some OSHPark style fab house for flex PCBs, but no love. I know flex PCBs can be fabricated just like any rigid PCBs, but they’re still too expensive for my hobby prototypes.

    Still a cool proof of concept!

    1. There is flex! Each OLED is built on it’s own flex pcb and then ribbon cable out to a flex prototype board from Adafruit. I also would LOVE a fab house for prototype quantity flex circuits but from what I can tell the production of flex circuits requires a mold for each shape you use and the processes for laser cutting and CNC do not scale well for batch volumes… Would really enjoy it if someone proved me wrong however!

      Here is the process I used:
      http://www.pcbfx.com/main_site/pages/start_here/overview.html

      Used their toner transfer and the laminator they suggested. Bought some copper clad kapton from ebay and several (14) tries later… That is part of the reason the current version isn’t entirely flex because it’s difficult to do the toner transfer over long traces especially on flex material.

      Adafruit carries a flex protoboard I used, and also the flex material “Pyralux” which is a brand named version:
      https://www.adafruit.com/products/1518
      https://www.adafruit.com/products/1894

      Good luck! Stay tuned for a second go! :)

      1. Thanks for the good information, Kevin. I know copper clad kapton is readily available and I’ve etched PCBs at home for decades (Ahtropologie catalogues rule for toner transfer, BTW)…but all of the flex designs I have in mind require multilayer fabrication with vias. I’ve actually stopped etching at home altogether, since OSHPark is so cheap and I can get 2-4 layer PCBs fast enough through them.

        I suppose vias could be accomplished using a laser cutter. Cut holes within decent sized pads, and solder blob the layers. Might have to try that sometime. And with a sufficiently powerful laser (100W+?) you might be able to prototype the flex circuit in one pass.

        Looking forward to seeing your next revision!

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