RESNA 27th International Annual Confence

Technology & Disability: Research, Design, Practice & Policy

June 18 to June 22, 2004
Orlando, Florida

Design of a Medium Dispensing Device to Aid in Art Creation by Persons with Disabilities

Yancey Arrington, Jason Herlehy,
Hime Bindhu Telugu, Bill Qu
Department of Mechanical Engineering
Yanyan Qian
Department of Industrial Design
The University of Texas at Austin, Austin, Texas.


Art education is an important subject in a growing childs education, and the methodology employed to draw out a students creativity are tried and true. These techniques don't work as well with disabled children and can greatly benefit in effectiveness with a touch of technology. This paper discusses the development of a fluid dispensing device as an approach to aid all students with creating art. The fluid dispenser aids a student to transfer/apply paint, glue and other fluidic medium onto their art projects without physical stresses or teacher invasion which accompanies other traditional physical squeezing methods.


The Rosedale school [1] is a complete program in the Austin School District which provides full developmental range learning environment for students with severe physical and mental disabilities. Rosedale provides the students under its care a greater quality of life by generously giving the care, attention and love the students in it's program require. They incorporate art into their program extensively as it provides each kid the ability to create unique works without requiring fine motor skill. Often the teachers have to use invasive hand over hand techniques to complete some of the steps in creating the art works. This device is designed to release the teacher from the burden of hand over hand invasive technique and gift upon the students the ability to make their art work that much more their own.


Every classroom at Rosedale is garnished with artwork created by the students and teachers along with bright visuals and other stimulating pictures. A large majority of the students have some form of gross motor control that does allow the students to take part in the creating of the art. Although in many cases the students have to struggle to apply the art mediums without causing a large mess for the teachers to clean up. Other students have extremely limited motor control which allows them to at most actuate a switch to operative assistive devices. One of the goals for the teachers is to allow the children to perform as much of the process while making art and often this may be thwarted with required teacher intervention. The design problem at hand is to create a device that will be student activated, highly mobile and allow the students to take more control in the creation of art while being safe, durable, flexible and low cost.


A rigorous and defined approach to the design method is extremely beneficial for this type of product development [2]. To begin, our group made several trips to the school to interview teachers, teaching assistants, office personnel and other faculty by using both a structured question and answer format and a more lax conversational style interview. These interviews allowed us to determine the customer needs and desires for this project. We learned that the students mostly use tempra paint dispensed from 500ml bottles and generic white glue for most of their art projects. We gathered also that a small "turn" around time was a requirement. The device had to be transportable, easy to set up, easy to use, quick clean up and most of all the device should not distract the teachers time away from the student. Our design was not very limited in the method and techniques we could employ within this device, this later allowed us to have over 10 distinct methods to dispense paint along with numerous small permutations of each method. Functional modeling aided in understanding the functions of the product and helped us to generate ideas. Using these ideas, the proofs of concepts were developed to test their feasibility. Results of the proofs of concepts quickly revealed to us that several of our ideas were to cumbersome or the performance was unsatisfactory.

Our team further limited the ideas down to two main and very different ideas through the use of evaluation matrices and pugh charts. The final two ideas left were a Cam-Squeeze method and a method which relied on the use of a peristaltic pump. We then greatly increased the depth of comparison in our pugh charts and resolved the final choice to be the Cam-Squeeze method. Our team favored this design in that it simulates the current hand squeezing method used, allowed for fast media changes and had virtually no clean up. The base design for the Cam-Squeeze employs a motor that actuates a rod/bar that physically squeezes the removable medium container against the device housing. It was also decided that the device should be handheld as well as having a "docked" mode in a station that could be placed on a table top or similar flat surface. The squeezing mechanism was designed to be highly adjustable and the motor speed is adjustable in order to vary the quantity of medium squeezed out.

An alpha prototype was developed based on the final Cam-Squeeze concept. We then presented the alpha prototype to our customers at Rosedale, where it was used by several of the teachers. Many insights into the problems with our design were gained while watching the teachers use the product. The housing for the device, as constructed, was much too heavy and required two hands to use and the mechanism for squeezing was crude and worked with drag and apparent wear. It was revealed that our construction of the housing from clear materials allowed the children to see the mechanism move and translate which was a source of stimulation for them. The team also realized that the loading of the medium bottles could be streamlined and the supporting structure reduced greatly due to the use of magnets.

The creation of the Beta prototype incorporated all of the design changes mentioned above coupled with an effort to make the design as small and unobtrusive as possible. The final product as designed and built is actuated by a 12V DC gearmotor which drives an aluminum offset circular cam. The circular cam pulls the actuation bar which squeezes the medium bottle in the same manner as a persons hand does. A threaded knob on the front of the actuation bar allows the user to adjust the distance the bottle is squeezed. This feature along with the ability to adjust the motor speed via a potentiometer in the circuit lets the user vary the dispensing of the medium from a short and fast squirt to a long thin bead of medium.

The housing of the device was constructed with strong, thin and lightweight polycarbonate in such a manner to minimize the need for extraneous support structure. This allowed us to get the device weight to approximately 2.3 pounds with 250ml of tempra paint loaded into the device. The device was also constructed to accept a signal from a typical jellybean switch used by all the teachers of Rosedale. When the switch is depressed the device completes one squeeze motion unless the user keeps the switch depressed where it will then run continuously.

The last feature incorporated into the device was the ability to quickly load, align and secure the medium bottles within the device. The premade medium bottles are secured to a base which has strong force magnets embedded within it. The device has a corresponding base acceptor built into the top of the device also with magnets embedded. The user only has to only get the medium bottle roughly into position and the magnets on both surfaces provide a guiding and securing force to mate the medium bottle to the device housing. At this point the medium bottle is upside down and paint would spill and flow from traditional bottles. Our team researched and installed a diaphragm type nozzle that will not allow the medium to flow unless the bottle is aggressively squeezed. The Rosedale teachers currently have the beta prototype in their possession and from their preliminary feedback have been incorporating the device into their curriculum plans. Video was created to demonstrate and describe the operation of our device at the Rosedale school and is available online [3].


The teachers at Rosedale conveyed to us that the device meet all of their hopes for a product of this nature. One of the concerns our team had a hard time addressing and which still remains a concern for the team is that the housing is not shock proof enough to withstand a fall from table height or more. This problem could most likely be solved by using a molded plastic housing incorporating braces and ribs. The actuation device, although lubricated, could come into some issues with binding over a long period of time. We had no way to test this and thus can only recommend periodic lubrication maintenance to the customer. The docking station was originally planned to be a table based support that would also house all of the medium bottles. This was changed in favor of a lighter and more aesthetically pleasing bent bar design with the teachers storing the medium bottles in their cabinets.


We feel that our device meet all the goals set forth by the Rosedale teachers in that it enables the teachers to afford the students with a greater and more rewarding learning environment. This device may also have many secondary markets such as condiment dispensing onto food and squeezing of toothpaste onto a toothbrush, these are currently being explored by our team and tested by Rosedale. Additional work and design iterations could transform this device into a refined commercial product able to withstand all the rigors of normal daily usage within the classroom setting.


We wish to express our thanks and gratitude to our instructors Dr. Kris Wood and Dr. Rich Crawford for the guidance, wisdom and motivation they enthusiastically provided. We would also like to thank Tom Hanson, Glyndar and Wayne for allowing us to come into their classroom and learn about their students and teaching processes which greatly helped us to achieve our goals.


  1. we believe, we practice, we achieve (brochure), Rosedale School
  2. K. N. Otto, K. L. Wood. Product Design. Prentice-Hall, Inc., NJ, 2001.
  3. for a demonstration of the customers, device features and device usage.

Primary Author Contact Information:

Yancey Arrington, MS,
UT University,
4905 Valley Oak,
Austin, TX 78731,
Office Phone (512) 422-2942

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