BBJJ (Blinky Ball-Jointed Jellyfish)

thingiverse

Sometimes a model on Thingiverse catches your eye, and you just have to add some light or lights to it. That's exactly what happened with this one. As soon as I saw it, I immediately downloaded it, hollowed out the dome and middle sections of the jellyfish, scaled them up as big as my trusty Printrbot could handle, and started printing. After finishing the print and assembly on Saturday, I had to wait a few more days for the electronics to arrive. It stands about 13 inches tall, and you can check out a video of it in action at: https://www.youtube.com/watch?v=M_Wk8TVNJt8. The bottom and tentacles are available on the original page. All I did was scale them up 1.8x (I think I scaled the tentacle end up more, maybe 2.6x - print one and see if it fits before you print the rest). In fact, print one of each of the ball-joint connecting pieces first and test for fit before you print everything. I had to make some minor size tweaks to get them to work on my printer. Print Settings: Printer Brand: Printrbot Printer: Simple Black Rafts: Doesn't Matter Supports: Yes Resolution: .2 Infill: 10 Post-Printing: Physical Assembly: Snap the ball joints together in the obvious way. I used a hot-air gun to thermal weld the middle section to the bottom section once all the tentacles were attached. I also welded on the center mast (to hold the electronics) and the latches. Still working on getting the latches just right. I used a hot-air gun and a set of pliers to punch holes for the charging port on the Adafruit PowerBoost 500C and my button. Electronics: In this build, I'm using: Adafruit Neopixel ring - 12x5050 RGB - https://www.adafruit.com/products/1643 Adafruit PowerBoost 500 Charger - https://www.adafruit.com/products/1944 Generic 1000mAh LiPo - http://www.ebay.com/itm/361366607971 An Arduino Nano that I picked up for a couple bucks from Aliexpress - any Arduino that will fit should work fine for this. Generic pushbutton A bunch of wires See the breadboard picture for my circuit. I'm monitoring the battery voltage and flashing a warning, then shutting down if the battery gets too low. I also destroyed the power LEDs on both the Arduino and the Powerboost. Heat them up with a soldering iron and they'll fall off or get brittle. Once brittle, a screwdriver and a little aggression will make the lights stop blinking. Code: Arduino code using FastLED is here: https://github.com/bobiam/blinky_jellyfish Pattern can be advanced via serial (send "n" noquotes) or button (interrupt on pin 2). It's relatively trivial to add a serial Bluetooth module like the cheap JY-MCU if you want to send patterns from your phone. I was happy with a button, personally. Why is this a Work In Progress? So the biggest reason that this is marked a WIP is that I'm struggling with the main jellyfish dome. Right now, mine's using a combination of the clips I posted, snipped to fit, hot-glued and welded to the dome and body. It's holding, but it isn't great and I don't expect it to survive for long, but I can lift it by the dome without it breaking off, so....we'll see. Things I've tried: Countersinking a nut into the main mast and gluing a bolt to the top of the inside of the jellyfish - too much stress, failed. Using an assortment of clips to try to make simple closures inside the jellyfish - so far they're all breaking off Doublesided tape - ugly and not strong enough Things I plan to try: Velcro Fishing line (down to the middle section and up through a hole in the dome) Posting it on Thingiverse and hoping someone comes up with something better? Also, lots of hacking with a heat gun. If I were going to make another one, I might try it the same way. If I were going to make a few more, I'd update the 3D models. There's a lot of hotglue, heatgun, and "close enough" going on in this build. It's not something that should be started lightly. You won't take this model, print it, and snap it together. Expect to do some heavy modifications to the parts after you print them.