Students Build a Better Pill Dispenser

Originally Published MDDI September/October 2003

R&D DIGEST

Four Johns Hopkins University (Baltimore) students have designed and constructed a computer-aided pill-dispensing machine that will enable a quadriplegic man to lead a more independent life. Using a mouth stick, the patient will be able to order one of up to 12 different medications stored inside the machine. Then, when the patient taps a "slam switch" (he has limited mobility in his right arm), the machine will dispense a pill through a tube leading to his mouth.

The patient, a 40-year-old former welder-mechanic, lost the use of his limbs in 1997 when he was struck by a car while crossing a street. He initially spent more than four years in a nursing home, where his regimen required that he take up to 12 pills each day. But he wanted to live in a more independent setting, so he turned to the Volunteers for Medical Engineering (VME), a Baltimore organization that aids people with unusual medical problems.

VME administrators referred the request to four students in the Senior Design Project course in the Department of Mechanical Engineering at Johns Hopkins. The students were to design, build, and test a device that would enable the patient to take his own medications, as needed, despite his limited mobility. The students could spend no more than $8000 to produce their prototype.

In the finished device, medicine is stored inside a locked box that houses 12 waterwheel-shaped dispensers. The box can hold a total of 180 pills. When a particular pill is needed, the patient uses a mouth stick to press a series of numbered buttons mounted on the front of the unit. He enters a security code first, then a number that corresponds to the medication he wishes to take. Next, when he taps the slam switch, a computer signals the appropriate waterwheel container to turn, dropping the pill into a Teflon-coated chute. The pill slides down the chute into a flexible tube leading to the patient's mouth.

The pill-dispensing device was one of 11 Johns Hopkins projects completed this year by undergraduates in the Senior Design Project course.

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