by Barbara Black

Students in a computer engineering courses have been playing with model trains lately, thanks to Professor Purnendu Sinha.

COEN 421 is an embedded systems software design course that fosters hands-on training in a specialized real-time systems lab. Using virtual software, students have to program the routing of three trains on a designated model track layout.

Controlling trains gave students a graphic sense of what could go wrong if their design was inadequate. As they wrote applications that sent impulses to the layout’s control board, they had to get a train to detect when another train was approaching on the same track, and move smoothly onto a siding to let it pass.

Sinha said he started them with the simplest challenge and worked up to more complex operations. “One of the hardest things,” said one of the students, “was to visualize each train separately.” They also had to avoid deadlock, where two trains would simply stop, facing each other.

“Embedded systems play an important role in our day-to-day life,” Dr. Sinha explained. “They are found in domestic appliances, automobiles, telephones, electronic gadgets, banking systems, nuclear power plants, avionics, and many other places.

“Nowadays, software is an integral part in most of these embedded systems. Software development for embedded systems requires structured, disciplined and transparent approach to efficiently create and maintain high-quality software and ensure the reliability of these complex software systems.”

“This design project is to develop a software system using object-oriented methodology that can manage movement of three miniature trains moving in arbitrary directions on a specified track-layout,” Sinha explained. “The objective is to avoid derailment and collision at any moment.

“The experiments are designed in an incremental manner so that students first develop all necessary software modules for controlling speed, track-switching mechanism, and so on, and ultimately, integrate them all.”

The students were working in the Electrical and Computer Engineering Department’s Real-Time System Laboratory (RTSL) on the eighth floor of the Hall Building. They also had a lab manual and a continually updated FAQ page on the lab Web site to help them come up with a good design and resolve any difficulties that arose over the design process.