Simple cylinder grasp #robot # hand #robothand #robotics #3dprinting

Not bad considering that all the servos are slaved to just a pair of joysticks and yet to apply any compliant or grippy layer. Nice to have the option to shape the grip with the separate actuation of the knuckle and the rest of the finger dof. Made entirely by #3dprinting with additional total cost of components required for the hand starting at around $300 USD. The stl files to print the hand and forearm are on github: The #cad for the arm and hand is freely and publically available down to a parasolid level at: The forearm and hand can operate as a stand-alone unit allowing unlimited axial rotation for rotational tasks like scrubbing. Some notes on printing: Designed and tested for high speed printing using a diameter nozzle and layer thickness except for the tendon spools (three type of Tendon_Spool_01 supplied, ymmv) and tendon hanger which benefit from printing at layer thickness or better. Test printed in CF nylon with nozzle and layer for structural components. To finish 3d prints to a high standard requires a fine sandpaper or emery board. Diamond coated steel nail files are a handy tool: Though my favourite diamond file is actually intended for maintaining whetstones, just a nice big expanse of diamond to use :-) - Amazon UK: - Amazon FR: - Amazon US: Additional components required are listed below. Please consider buying via the Amazon links where available to help fund the robot development. The biggest cost item are the servos: 16 slim microservos like the Emax ES3301 (approx $6.6) are needed for a total of approx 100 - 200 bucks. The hand in the video uses Emax ES3302 but any slim micro servo that fits inside the envelope of 23.2*9.2*24.1 will do. Emax themselves make four variants at this size with plastic or metal gears and using either digital or analog control technology. ES3301 (approx $6.6) ES3302 (approx $9.2) ES3351 (approx $8.5) ES3352 (approx $12) Official website: 2 micro servos needed for wrist flexion and extension (required). Feetech SCS2332 - are recommended. These are serial bus driven servos over allowing a greater range of controlled rotation. They cost around 35 bucks each plus delivery obvs. If you prefer to use a traditional servo for simplicity they can be substituted by any servo that fits inside the envelope 23.2*12.1*. The trade off is the reduction of the powered range of motion of the wrist to about half. 1 standard servo needed for axial wrist rotation (optional) Feetech SCS15 - or any servo that fits inside the envelope 40*20*. Reduces powered range of motion to about half and the loss of a continuous rotation option. The rest of the components are relatively inexpensive: 2mm diameter steel pins - alternatively cut lengths from a wire coat hanger or in Europe order direct from Otherwise kits are available on Amazon: UK: FR: US: M2 screw and washer kits, or also in Europe from UK: FR: US: M2 brass threaded inserts M2 * 4mm long * Note that the type required has a plain section between the knurled ends to allow attachment of the tendon in the fingertip. UK: FR: US: Kite or fishing line for tendons and ligaments - Sufix 832 is the best I know of for longevity, the 80lbs breaking strength is stiff enough to thread easily and most readily available in the US. UK: FR: US: Ball Bearings 6*10*3 - Need 50 for a hand, packs of 10 available which are enough for the sample finger. UK: FR: US: Ball Bearings 2*6*3 or 2*6*2.5 - Need 6 for a wrist. UK: FR: US: Ball Bearings 15*21*4 - Need 4 for a wrist. UK: FR: US: ptfe tubing 2mm OD 1mm ID, sold for 3dprinters. UK: FR: US: