Ralph: A fingerspelling
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.
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
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
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