Introduction: 3D Printed Tentacles LED Headpiece

This tutorial will explain how to create and assemble 3D printed tentacles, lit up by smart programmable LED's, headpiece.

I'll upload a different Inscrutable about modeling these tentacles in few easy steps using Rhino.

You'll need access to a 3D printer with white filament, I would say its roughly 10 hours of overall printing time.

Step 1: Materials and Tools: Everything You'll Need


Hot glue gun - for attaching the tentacles to the plastic head band

3D printer + white filament (I used PLA)

Soldering kit

AVR programmer - you'll need to be able to program the ATtiny85 micro-controller. This tutorial will explain how to do it with a simple Arduino Uno, but since Im doing this quite a lot I prefer to use this ready-to-go solution by Sparkfun.


LED strip - I used 30 led/m. You'll need only 7 LED's so 1m would more than enough.

Controller - ATtiny85 is my pick of choice in these projects because of their size and easy of handling.

Battery - A 350mah Lithium-Polymer battery would give a nice battery span while being small-sized enough to be mounted on the head band.

Plastic head band - The wider the better. 1" (2.54cm) is the best I've found.

DIP8 socket - Just a socket for the controller. Its a safety net in case the controller would have to be replace or re-programmed.

On/Off switch - No need to explain.

10uF electrolytic capacitor - to stable the input voltage in the capacitor

Micro JST connector - for the battery

30mm Heat shrink - to protect the control unit. Any color would do but transparent one would enable you to show it off ;)

3 wire cable - No need to explain

Step 2: 3D Printing

The first task in order would be to get the 3D printing part off the way.

Use your favorite 3D printer to print 2 of each attached STL except for Coral 3 which you will only need one - the center one.

There's no special printer setting except for using Brim of 2-3mm. It would help print the tentacles and would later help to stick them to the head band.

Step 3: Preparing Electronics and Lights

This step is where most of the work is and where special attention is required.


Solder the female side of the connector to the battery's wires. Protect the soldered (and exposed) part with heat shrink or duct tape of any kind. this especially important as short circuit between the wires of the Lithium-Polymer battery could lead to serious heating/fire/explosion of the battery, so pay attention.

LED strip

cut 7 LED's length out of the strip. Mind to cut in the middle of the connection like shown in the picture.

When come to solder, mind that individually addressable led strip have direction. Follow the arrows on the strip, they're mark the direction.

Controller circuit assembly

See that the DIP8 socket has a half circle cut, this will help you get the direction of the ATtiny in the socket.

Place the half circle side away from you and then solder the wires as shown in the diagram:

  • LED strip - (+),(-), Data. Data pin in connected to pin 2 on the controller.
  • Capacitor - between the plus and minus of the socket
  • Switch and battery (male side) connector

Finally, cut a piece of the the heat shrink in a way it would cover the LED strip connection all the way to the switch. Then, use a hot air gun or just a lighter to heat it until it shrinks.

Program the ATtiny85

Use either an Arduino Uno or designated AVR programmer to upload an animation program (mentioned at the beginning of the tutorial). I used an example sketch out of FastLED library called "ColorPalette". After installing the library, open the Arduino IDE -> File -> examples -> FastLED -> ColorPalatte

Make sure to adjust the parameters in the sketch to match this project's setting, i.e 7 LED's and Data pin 2.

Test it now by turning it on. If it doesn't work, now would be the time to solve it. If it shines as expected, move on.

Step 4: Attach the LED Strip and Controller to the Head Band

Position the strip in way that the center LED on the strip is facing straight up.

Make sure that there will be enough room to tape the battery below the controller.

Hold the strip in place with clear duct tape in few spots. The hot glue later will burry the strip anyways.

Use some duct tape to hold the battery to the head band. There are probably more elegant ways of solving this, but Im just to lazy for that.

Step 5: Attaching the Tentacles to the Head Band

Carefully apply hot glue to the extended base of each tentacle (remember you left the printed Brim? this is where it come in handy). The Brim might melt a bit, no worries. Then place it on top of the LED in a way the LED would be directly in the middle of the tentacle base.

After you got the tentacle in place, add a bit more glue outside the tentacle so it would hold firm.

*You might want to apply the glue slowly so it would have time to cool off a bit before meet the 3d printed part as it might deform due to high temperature.

Thats it! If everything went well, it should be ready to go.