| Home | Technology Transfer |

photo of Ralph fingerspelling hand

Ralph: A fingerspelling hand

Investigators: David L. Jaffe, MS; Douglas F. Schwandt, MS; and James H. Anderson, JEM

Summary: Ralph is a computer controlled electromechanical hand that serves as a tactile display for persons who are deaf and blind. In operation, the deafblind user feels the hand as it moves and interprets its motions as letters corresponding to the American One-Hand Manual Alphabet, a technique known as tactile fingerspelling. The hand is controlled by a microcontroller whose software translates incoming serial ASCII data into control signals that operate eight servo motors. These servo motors pull on the fingers' mechanical linkages causing them to flex. Ralph can use information from a computer's serial port, modem, TDD, or computer interface to a optical character recognition scanner, voice recognition system, closed caption decoder, or stenography machine facilitating translation of e-mail, telephone conversations, printed text, spoken words, subtitled television programs, or classroom/conference/courtroom interactions into fingerspelling.

Brief Project Description:
Ralph is a computer-controlled electromechanical hand designed to be a receptive communication aid for people who are deaf and blind. It offers these individuals improved access to computers and communication devices in addition to person-to-person conversations. Driven by microcomputer controlled servo motors, this product also has potential for prosthetic, robotic, hand therapy, and virtual reality applications.

Core Technology:
Ralph consists of two major elements: its mechanical and computer systems. The fingers are made in three segments, each mechanically linked to the next. A rod at the base of each finger is driven by a servo motor to make the finger flex. The microcontroller system generates and coordinates the servo control signals for all fingers.

Specific Technology Transfer Opportunities:
The Rehab R&D Center is prepared to work with a company on the following projects based upon the technologies developed for Ralph. Funding options include those from SBIR proposals or Cooperative Research and Development Agreement (CRADA). The company should have experience in one or more of the following areas: microcontroller technology, servo motor control, mass production techniques, and devices for people with disabilities. The Rehab R&D Center will contribute its 8 years of fabrication, mechanical design, and computer expertise toward a commercial prototype.

1. Fingerspelling hand: The Center is looking for a company to bring the fingerspelling application to commercial availability.

2. Prosthetic hand: The mechanical system of Ralph could form the basis of an improved prosthetic hand. The user would operate the hand by emg signals picked up by surface electrodes on the skin.

3. Robotic end-effector: A three fingered mechanical hand modeled after Ralph could be employed in a robotic manipulator. Each finger could have multiple segments and sensors for feedback. The hand could be remotely operated.

4. Hand therapy: A wearable version of Ralph would allow people with arthritis to engage in range-of-motion exercises. Moving the fingers of the good hand wearing a dataglove would cause movement of the fingers of the other hand.

5. Virtual reality: A wearable version of Ralph would permit the user to obtain force feedback during manipulation of virtual objects. The finger positions of the user's hand could also be acquired.

For additional information contact David L. Jaffe.

Button Bar

People Projects Publications Resources Home