Engineering students at the University of Arizona have designed and built a remote water-level detector that will become an integral part of a water system serving 10,000 people in Ghana.

The water system in the North Tongu District of Ghana's Volta Region was developed by the university’s chapter of Engineers Without Borders, and eventually will serve 30 villages.

The water system includes a dam, which backs up the seasonal flow from a small stream, a filtration plant, pipes, pumps and a hilltop water tank that delivers water by gravity feed. The system has been operating since September 2005.

"The hilltop tank is fed from a pump at the base," says Matt Engelman, an electrical and computer engineering senior. "Where our project comes in is in monitoring the water level in that tank," he says. "There's no way for it to be checked without having someone run to the top of the hill to look inside."

Knowing the water level is critical to the system because it was built at low cost with local labor, and might start to leak or rupture if overfilled.

How It Began

The project didn't start out as a senior design effort, senior Kevin Carr explains. It began when the students were juniors a course that teaches students about computer systems, memory devices and interface design, among other things.

While in the class, Carr and Engelman, along with senior Bill Richardson, an Engineers Without Borders member, saw the need for a water-level indicator and decided to build a proof-of-concept device for the class.

"We built an ammo can with an ultrasonic range finder and a microcontroller that basically detected the water level," Carr says. "We found that it worked, and decided we actually should build the system for our senior project to meet a real need."

Since it wasn't one of the projects already approved for the senior design class, the students had to organize the project, get approval and arrange the funding to complete it. "It's an unusual project because most other senior projects are sponsored at the start," Engelman says. "But since we proposed the idea, we also had to arrange for funding."

The System at Work

The ultrasonic sensor works much like a sonar system, Engleman explains. It sends out a sound wave, which is reflected back from the water. The amount of time needed for the signal’s round trip can be converted to distance.

Once the water level is determined, the information is transmitted wirelessly to a health clinic 5 miles away and to another receiver at the pump house, nearly 2 miles away.

The indicator and transmitter are solar-powered because no electrical connection is available near the tank, and the signal is transmitted at 900 megahertz.

The system now is completed, and will be taken to Ghana and set up by Engineers Without Borders volunteers within the next few months.

Engleman says the six students who designed and built the water-level indicator have gotten a real sense of accomplishment because it wasn't completed just to satisfy a requirement or for a grade. "We're all really pleased to have been part of this project because of the humanitarian aspect," Engelman says. "It's a device that's going to be deployed in the real world, and is really going to help people."