RESNA 27th International Annual Confence
Design of Assistive Technology Device to Support Playing of Percussion Instrument
Assistive technology is an industry that focuses on improving the independence and quality of life for those who live with severe disabilities, but is lacking in products available for leisure activities such as playing musical instruments. With this need in mind, a device has been created to give these people the independence and the ability to play percussion instruments such as drums, tambourines, small shakers, and many other instruments. This paper presents the process followed to develop this product, and details the features, functions, and outcome of the device with regards to the assistive technology market.
Music, percussion, instrument, product design
The Rosedale School, located in Austin, Texas, is a member of the Austin Independent School District (AISD) and provides a positive learning environment for students with severe or multiple disabilities. The mission of Rosedale includes creating a better quality of life for students by increasing their self-confidence and independence. Music is a particularly good medium for interaction with and between the students. In the past, the use of music in the classroom has consisted primarily of action taken by teachers, and not by students. Either students watch and listen to teachers sing, clap their hands, play small percussion instruments such as tambourines, maracas, etc., or the teachers are using a very invasive hand-over-hand method to help students play their own instruments. With this method, the student cannot feel the instrument being played, but instead feels the teacher's hand. The purpose of our device is to eliminate the teacher from the equation and give students the opportunity to play percussion instruments themselves.
Many of the students at Rosedale do not possess the physical ability to play percussive instruments, but they respond very positively to these types of sounds, and enjoy interacting with teachers, staff and other students in a musical environment. The goal then, is to develop a system that assists people with physical disabilities to play percussive instruments independently. This not only allows students to perform individually, but to participate within a group of teachers and students without relying on a teacher to help them play the instrument. This also strengthens self-confidence by showing them that they can control the sound produced. Thus, the design goal for this project was to develop a device to assist persons with limited fine motor skills in playing percussion instruments.
The design team implemented a structured design methodology in order to carry the design from problem statement to problem solution and physical reality. Our methodology is laid out in Product Design , by Otto and Wood (1). The first step in thoroughly identifying the problem was to determine the specific needs and expectations of our customers, the students and staff of Rosedale. Teachers, staff, professional musicians and music therapists helped us to determine a set of needs by their participation in written questionnaires and oral interviews. We also gained great insight into the current methods for playing percussion instruments by observing the students and teachers at Rosedale. With our customer needs and specifications in mind, we proceeded to brainstorm and derive a broad range of ideas with the goal of creating a technologically novel product to best suit the needs of our customer. Once these ideas were documented, they were combined into fully functional designs. Prototypes were created and used to collect data from simple tests and customer feedback on these introductory designs. The data was used to numerically compare the ideas based on the needs of the customer and determine the primary design concept for the project. An Alpha prototype was created, tested, and customer feedback was obtained. The information gathered in this process was used to make changes to the design which were then implemented in the Beta prototype.
The final product of our design is based on two commonly used systems. One system imitates the spring-powered bass drum pedal found in a standard drum set. A rotating cam is used to draw back a drumstick that is pulled forward by the force of an attached spring to strike a snare drum placed in front of the machine on our custom designed drum stand. The second is a double-rocker mechanism such as the one found in automobile windshield wipers. The mechanism rocks back and forth to shake small instruments such as a tambourine or shaker. The instruments are attached directly to the end of the rockers. A larger instrument such as a tambourine is attached directly to the bar by the use of a simple bolt and wing nut that can be hand-tightened. Other smaller shakers can be attached to the other bar using an adjustable clamp mounted to the bar. This feature was added after the Alpha prototype at the request of Rosedale teachers to incorporate student-made art projects such as small shakers.
Mechanical power is provided to the system by a small DC gear motor, attached directly to the rotating cam. The motor was selected to provide the system with enough mechanical energy to play the instruments at a sufficient volume, while ensuring that it is not so powerful as to cause injury to students or teachers if they grab moving parts or obstruct the path of motion. One important feature is that the voltage to the motor can be set at different levels from 6 volts to 12 volts through the AC to DC adapter. This allows the user to adjust the speed of the motor, and therefore, the speed of the instruments.
Control of the system comes from the PowerLink 3 control unit by AbleNet Inc. While providing electrical power, the control unit uses a switch such as the BIGmack to allow the student to turn the machine on. We decided to use this type of control unit because they are already in use throughout the school, and the students are all familiar with the switches. In addition, the Powerlink 3 allows the teacher to set the length of time the machine will operate.
The moving parts of the machine described above were designed sturdily out of strong materials to ensure that the machine's durability. With heavy-duty parts such as these, safety is a prime concern; thus the casing of the machine was designed with user safety in mind. The sides of the case are gently contoured to eliminate sharp corners and create a modern and engaging shape. Windows are cut out of the sides and covered by polycarbonate sheeting that is highly impact resistant so that students can safely view the machinery. The top and back of the casing are polycarbonate as well. The top panel is hinged so that it can be easily opened for maintenance purposes. Some parts such as the drum stick and rocker arms are located outside the casing, but exit the case through slots designed to minimize pinch points. The interior was painted bright, primary colors for additional sensory stimulation.
In order to maximize the functionality and keep the system organized we mounted the system on a small rolling cart approximately 30 inches in height. This puts the machine at a height that is easy to see for most students in wheelchairs, as well as those who can stand. The cart provides a convenient storage area for accessories and other instruments and makes for easy transportation from classroom to classroom.
Once the Beta prototype was fabricated, we were able to test the device with students and teachers at Rosedale. All students who were given the switch were able to activate the device and all showed a positive response to the sounds and motion of the machine. We noticed a greatly improved level of participation, recognition, and activity from the students during their first use of the device. In a formal presentation of the device at Rosedale, there was profound interest in producing duplicates of the device for other teachers, as well as marketing the device to music therapists. Overall, the integral portion of the machine, excluding the rolling cart and PowerLink control unit can be reproduced for under $150, and could be further reduced with attention to design for manufacturability. The device has far exceeded expectations regarding student interaction and recognition, and due to its robust design, should serve the students of Rosedale for an extended period of time without failure.
The percussion assistant device provides Rosedale students with a product that they can operate completely independently to create musical sounds and lively motion that will capture not only their attention, but that of others in the classroom. This device gets students involved in an area of education that strengthens not only the art of music and personal expression, but can be an aid in other areas of education that are based on rhythm, such as counting or math. The system is easy to set up and use, making it a valuable addition to any classroom. This design aids the goal of Rosedale, and any program designed to help students with disabilities, which is to increase the independence of its students and have a positive impact on their quality of life.
We would sincerely like to thank the faculty and staff of The Rosedale School, especially our friends in Room 15 for the advice, ideas, support, and warm welcome into their classroom provided to our team in the development of this product. We are also sincerely indebted to Dr. Kristin L. Wood and Dr. Richard H. Crawford for their insight into the design process as well as giving us the advice, motivation, and support necessary to drive this project from idea to reality.
The University of Texas at Austin,
Assoc. V.P. for Research,
1 University Station Stop R2500,
Austin, TX 78712,