Challenge
In cooperation with MOVIA (public transportation for Copenhagen) a system for extending green light for public transportation was requested. The objective was to reduce passenger traveling time and reduce CO2 emission by avoiding the bus standstill on red light.
The idea was to have a complete link between the bus towards the traffic light. Our part was interfacing to a web service in order to gain access to the real time data of busses. A discrete signaling protocol was designed for interfacing the main traffic light controller.
A backend system should support reports on status and statistics and providing a live situation view.
Solution
In order to interface to MOVIA a device capable of running .net code was needed. The solution was a comprise of an embedded solution and a more traditional PC based board.
The solution was to use Windows CE, which has been around since 1998. It is not widely used, but development in C#/.Net using Visual Studio for in-circuit debugging was a well-known combination with a lot of benefits.
Furthermore, WindowsCE had the feature of being ‘embedded’ – e.g. supporting flash storage and headless operation. The hardware solution used a Toradex ‘Computer On Module’. Adding gsm modem communication and IO was an easy part.
The system was commissioned back in 2010 but it is still in operation and has been extended several times, complying more than 200 light crossing. It handles over 5000 green light extension requests from busses every day.