Gesture Controlled Soft Robot Tentacle

About the project

A soft robot controlled with a wrist mounted accelerometer.

Project info

Difficulty: Moderate

Platforms: AdafruitSeeed Studio

Estimated time: 6 days

License: GNU General Public License, version 3 or later (GPL3+)

Items used in this project

Hardware components

coin cell holder coin cell holder x 1
Coin Cell Battery CR2032 Coin Cell Battery CR2032 x 2
dragonskin 10 dragonskin 10 x 1
ecoflex 00-30 ecoflex 00-30 x 1
Adafruit Silicone tube Adafruit Silicone tube You need 6 tubes, but their long enough that you can cut each one in half. x 3
Seeed Studio Grove - 2-Channel SPDT Relay Seeed Studio Grove - 2-Channel SPDT Relay I used 6 single channel relays. x 3
Adafruit air valves Adafruit air valves x 3
Adafruit air pumps Adafruit air pumps x 3
Arduino Nano 33 BLE Sense Arduino Nano 33 BLE Sense x 2

View all

Hand tools and fabrication machines

Soldering iron (generic) Soldering iron (generic) x 1
3D Printer (generic) 3D Printer (generic) x 1


I wanted to make a simple soft robot. The soft robot has 3 chambers inflated by air pumps. Once made I created a small wrist mounted accelerometer (Arduino nano 33 ble sense), to control the movements of the tentacle in a fun way. The tentacle mold was made with a mixture of ecoflex 00-30 & dragonskin 10 (ecoflex 00-50 may be enough, so that the cost goes down..... but it wasn't tested). The air pumps & the the air valves are all controlled with one relay each (making that part of the code super simple).

Schematics, diagrams and documents



CAD, enclosures and custom parts

Watch case

A watch case, you need a nano 33 ble without pins & a power source (I used 2 coin cell battery holder from adafruit) use small screws to hold everything to the 3d printed case. I used nylon straps for the wrist part.

Go to download

inner design_mold_tentace

This forms the inner ridges in the silicone tentacle. Fit the sticks one by one in the triangle & solder them together.

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Tentacle mold

Tentacle mold (print 3 times) screw them together, once the silicone is mixed insert the inner design parts & slowly pour the silicone.

Go to download

Air pump/air valve cases

Case for the adafruit air pumps & air valves.

Go to download

V2 tentacle mold

A second version of the tentacle mold (cut in half, easier to print, print at different times). Need to print both pieces (top & bottom pieces 3 times each). After, solder top and bottom piece together.

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Tentacle base

The base of the tentacle, solder the two pieces together. Once your silicone tentacle has been made, put some silicone on the 3 circles and press the tentacle together with the pla. 3 small square holes in the bigger piece are for you to feed the air tubes through. The bottom of the smaller piece contains a small tube for you to connect the air tube to.

Go to download



Simply a arduino nano 33 ble sense.


An arduino nano 33 ble sense, with 3 air pumps & 3 air valves


Photo of blight3d28


Hi, I'm Computer Scientist, love robotics & programming.


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