Step 2: The Design

Each of the fingers uses two sets of four-bar linkage. I will show you how this works with the two pictures of the finger below. 

For the parts, I was able to get them laser cut out of acrylic at my local hackerspace, HeatSync Labs. Acrylic is an excellent material for smaller loads and basic testing, but if there is any sort of major strain on the finger, you run the risk of snapping the parts. Instead of acrylic, it would be better to get the parts made out of metal for larger loads. 

There is no scale on the .dxf files. For the fingers, the holes should be 2.8mm. For the palm, the rectangles are 20x40mm. I used Hitec HS-322 HD servos, and they fit perfectly. You will have to take the servo case off and put it back together in the hand since there is a small lip where the wires come out. 
12203madman2 years ago
How much does it cost to make
macgyver603 (author)  12203madman2 years ago
The total cost was somewhere in the ballpark of $150-$200. If you have any of the materials already, the cost may be a bit lower, and it also largely depends on where you can find the parts. I was able to find pretty much all of the electronics I needed on sparkfun.