Learn how to program, use sensors, and micro-controllers! Join our movement to bring high-functional prostheses to the market!
About this project
BRG presents a 3D printed robotic hand that better mimics natural hand movement that anyone can easily learn to control. The Hobby Hand 2.0 is an open source test bench that will preview technologies borrowed from the Nu-Hand (our previous Kickstarter attempt).
The Hobby Hand is an affordable kit that will aid in the further development of our 3D prosthetic hands. This platform is ideal for hobbyists, tinkerers, DIYers, and those who are interested in learning about robotics. The ‘Hobby Hand’ can also be used as an introductory educational platform for programming, micro-controllers, analog sensors, and hardware.
Our ultimate goal is to bring highly functional robotic prostheses that are affordable! Join and support our movement to educate the next generation while improving our designs through continued research!
Hobby Hand 2.0 Changes
The Hobby Hand frame is now a ‘split’ frame design. This allows for additional movement during flexion. The improved range of motion will increase the overall grip size (allows for larger objects to be held).
Subtle changes were made to the fingers to improve manufacturing as well as durability. The thumb joint has been improved to allow for a larger range of motion and controllability. Finger bases have been redesigned for lateral movement (example will be shown on an update).
We also reduced the price of the Hobby Hand by using 3rd party manufacturers of the Arduino boards.
Hobby Hand Design Summary
The Hobby Hand contains 5 servo motors for lateral movement and a servo motor frame that houses 5 additional servo motors for flexion. A top piece mounts the hand onto the servo motor frame that guides the flexion cables to the servos.
A servo motor base contains the Arduino mega/uno + servo shield that attaches under the servo motor frame. This is the ‘control’ center of the Hobby Hand where all of the motors, sensors and additional peripherals are attached to the board. We are currently using servo motors to keep the costs down for the Hobby Hand Kit.
Each finger has a total of 4 bands that saddle the center line (symmetry in plane) to maximize the stability of each finger. The elastic bands bring the finger back to its original position after closing. A rear covering is attached to the back of the Hobby Hand frame.
How do you control the Hobby Hand?
We plan on refreshing the design of the analog controller board to include a 3D printed case and proper knobs as our campaign progresses. We have developed an analog board of potentiometers that can control flexion and lateral movement of each finger.
What if I want to assemble the Hobby Hand myself?
We got rid of the ‘unassembled’ kit because it created too many rewards. However, if your heart is set on assembling the kit yourself you can inform us via survey after the campaign is over. Unassembled kits will have a quicker delivery time.
The unassembled kit requires soldering and the use of basic hand tools (screwdrivers, pliers and scissors). All kits will include a step by step instruction manual along with tutorials and other resources on our website to help you become proficient in no time!
What else can the Hobby Hand do?
The Hobby Hand comes with a mini breadboard that is attached to the servo motor frame. This allows for additional analog sensors (light, infrared, ultrasound, sound, muscle and others), LED’s and speakers. Examples and tutorials will be provided on our main website.
What happens if a component fails on the Hobby Hand?
The great thing about the Hobby Hand is that it is completely modular. Every component can be quickly replaced or even repaired. A catalog of parts and part numbers will be included in the instructions manual for orders. The Hobby Hand Full and Lite versions will come with additional parts (high frequency moving/load bearing components).
- Materials: The Hobby Hand 2.0 is 3D Printed using either PLA or ABS thermoplastics. PLA is more environmentally friendly, whereas ABS thermoplastics allows for additional smoothing after the parts are 3D printed with acetone vapor.
- Power: The Arduino mega requires an external power adapter to drive the servo motors. A 5V – 4 Amp A/C Adapter is included with the complete Hobby Hand kit.
- Hobby Hand Scale: Is it life sized? Yes! The hand was modeled after Tim’s own hand and is life sized with roughly the same proportions.
- Hobby Hand Movement: The Full version has 5 servo motors that generate lateral motion (side-to-side finger wagging) and 5 servo motors to close each finger. Each motor can move independently. The ‘Lite’ version contains only 5 servo motors to close (flexion) each finger. The hand has a ‘split design that increases range of motion during flexion (i.e. allows for better grip).
- Hobby Hand Grip Strength: The hobby hand runs off a tension cable that is fixed to a pulley wheel. The stall torque of each servo motor ranges from 1.8 – 2 kg*cm (1.56 – 1.74 lbs*in).
- Hobby Hand Lateral Strength: The hobby hand lateral movements will be generated using rigid metal rods (similar to RC airplane ailerons). The stall torque of each servo motor ranges from 1.5 – 1.8 kg*cm (1.301 – .56 lbs*in).
- Hobby Hand Weight: The complete assembly weighs roughly 3 lbs (10 servos, Arduino board, Hobby Hand, base and analog controller).
Level 01 ($5 USD) – Thank You Letter + Updates. We will sincerely thank you for your support and you will have access to all of our updates on Kickstarter!
Hand will be mirrored (both left and right hand).
^Find some friends to go in on this deal of the century :)
Social Media: Show your support for Biomechanical Robotics Group through our different social media channels! We understand that not everyone will be a backer, but we do appreciate those that are ambassadors for our cause.
Risks and challenges
We do not foresee any challenges in acquiring the materials to produce the Hobby Hand. However, we are at the mercy of distributors to receive parts and components in a timely manner.
Design has been completed, there may be additional optimization that will not affect delivery dates.