Robot hand || bionic hand prosthesis prototype

This bionic hand is controlled by an Arduino Nano V3 and uses 4 15kg servo's to move the index, middle, ring and little finger and 3 9g servo's to rotate the thumb and pull the thumb and the fingers open. This bionic hand it's structure is modelled after my hand so I could make a gel10 mold that would fit snug around it.

I originally wanted to integrate some force feedback in the finger tips by using some small pushbuttons. This didn't turn out to well because the wires from the pushbuttons in combination with the gel10 mold caused to much friction in the joints of the fingers and the fingers had to push to hard to activate the pushbuttons.

I'm now going to do some tests with current sensors so I can measure the current going to the servo's and when the current goes above the normal level then the servo's would stop (that's the idea).

Finger wiring schematic:

Bionic finger wiring diagram V2

Circuit diagram:

Circuit diagram

Here are some close-up pictures of the wiring on the bionic hand:

Bionic hand wiring close-up 1

Bionic hand wiring close-up 2Bionic hand wiring close-up 3Bionic hand wiring close-up 4Bionic hand frontBionic hand back


STL-files and the Fusion 360 source files can be downloaded here:

Arduino code can be downloaded here

Circuit diagram can be downloaded here

1 × 3D-printed parts
4 × 15kg Servo'slink:
1 × 2S Lipo 7.4Vlink:
2 × 5mm red LEDlink:
2 × pushbuttonlink:
2 × 200 ohm resistorlink:
1 × 2.54mm Single Row Male Pin Header Strip For Arduinolink:
3 × springs from old pens
1 × 1mm diameter steel rod or similar as shafts for the fingers
1 × nylon wire
1 × somewhat larger spring but less stiff as the springs from the pens. This spring brings the thumb back to it's original position. I just used one I had lying around and I thought was gonna work
2 × 9g servo'slink:
1 × Arduino Nano V3link:
1 × DC-DC Step Down Adjustable Constant Voltage Current Power Supply Modulelink:


  • “Hello Brain, is it possible to create a prosthetic device similar to yours but use it as a hand exoskeleton with the help of gloves as attachments for the hand?”

    Aime Nya
  • Hi Brain, I just purchased the 3d models and can you explain or post something regarding the nylon wiring? I think it should have been included in the 3d model. Thank you.

  • @Kishore, could you explain to me why you don’t want the pushbuttons, because without them you’re not able to select and execute programs unless you’re going to use another way to control the arm with for example muscle sensors.

    Brian Brocken
  • Please can you say circuit diagram for this without push button, we are in need to complete our mini project. We inspired by this video and started but it is now pending please help very urgent


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