Taking medication is something thousands of people do daily, without giving it a second thought. You open the bottle, pop a pill into your mouth, and wash it down with a big glug of water. But what if you can't open a bottle, grasp a pill, or fill a water glass yourself?

After more than four years in a nursing home, Robert Arthur Williams, a quadriplegic with limited use of his right arm, wanted to live in an independent setting. Before that could happen, he needed a way to have his medication dispensed as needed, 24 hours a day. A device designed by two Johns Hopkins University undergraduates made that possible.

The undergrads, Ross Whitaker and Paul Stemniski, designed a computer-guided pill dispensing machine that allows Williams to take the medications he requires, without the assistance of his live-in helpers.

The pill dispenser holds 180 pills, divided among 12 dispensers that each has 15 compartments.

Williams had sought help from Volunteers for Medical Engineering, a Baltimore organization that provides customized equipment to people with medical problems. VME signed on with the Johns Hopkins senior design class.

The dispenser was developed during the yearlong class taught by Andy Conn, a senior lecturer. The course pairs two students with a sponsor who needs a custom-designed solution to a real-world problem.

In this instance, VME was the sponsor. The students are given a $10,000 budget that has to cover everything, ranging from design through prototyping to the building, fabrication, and testing of the machine, according to Conn. "They start out with a statement of need and find a way to turn it into a working thing," he said.

The working pill dispenser, which the students referred to as ASSIST (Automatic System for Sensing Illness and Sending Treatment), turned out to be a very complicated device.

The major components of the device are a computer-activated control console, an acrylic water wheel-type dispenser, and an LCD screen. The console is used to select medications. All of the pills are stored in a locked box that contains 12 waterwheel-shaped dispensers. Each wheel has 15 pill compartments, enabling the device to store a total of 180 pills.

Robert Arthur Williams uses a mouth-stick to choose the medication that he wants the automatic pill dispenser to release.

To dispense one of the 12 medications that he takes throughout the day, Williams uses a mouth stick to push buttons on the console to enter a security code and select a medication. Next, he uses his right arm to hit a slam switch, a button that can be activated with a tap from any direction. This activates the computer, which signals the appropriate container wheel to turn. The wheels rotate one compartment, then drop the selected pill into a Teflon-coated chute. Gravity causes the pill to slide down the chute and into a flexible tube that leads to Williams' mouth. Water bottles and straws are mounted on his wheelchair and at bedside to help Williams swallow the pills.

The system uses no motors. Rather, the wheels are operated by a programmable logic controller that activates a push solenoid, according to Stemniski. The solenoid increments gears by two teeth with each activation of the slam switch. The gears are attached directly to the waterwheel dispensers. The screen displays the status of the system, including which pills Williams has selected.

Stemniski and Whitaker worked closely with Williams to make sure the device was as friendly as possible, and that it met his needs. They constructed the device largely from off-the-shelf parts, and did all the programming themselves.

Needless to say, the students passed the class with flying colors. Stemniski, who majored in mechanical engineering, is pursuing a graduate degree in the subject at the University of Michigan, where he is focusing on haptics. Whitaker, who majored in biomedical engineering, is working as an engineer for a cardiovascular device company, St. Jude Medical Inc. of St. Paul, Minn. Two other students who worked on the project, Mark O'Leary and Yo-Rhin Rhim, who both majored in mechanical engineering, are pursuing master's degrees at Johns Hopkins.

The satisfied client, Williams, said that he can now take care of himself for longer periods of time, thanks to the Rube Goldberg-esque pill dispenser.

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