Repurposing an automated prepare management unit as a automobile speedometer

We’re simply now getting semi-autonomous self-driving capabilities in vehicles, which allow them to adhere to posted velocity limits and preserve their lanes. However trains have been doing the identical factor for a very long time — nicely earlier than machine studying and pc imaginative and prescient grew to become ubiquitous. How did they do it? With ATC (automated prepare management), which Philo Grey and Tris Emmy Wilson demonstrated by repurposing an ATC unit from an MBTA Pink Line prepare as a automobile speedometer.

Trains don’t need assistance steering, as a result of they’re on rails. These rails are additionally the key to ATC operation. Being conductive, the rails present a path for speaking information. That’s truly bidirectional in a manner, as railway management methods use the circuit accomplished by the presence of a prepare as a swap to find out the prepare’s place. On the similar time, it sends information to the prepare by means of the “audio frequency monitor circuit.” The ATC unit reads that information and controls the prepare velocity accordingly, whereas additionally indicating the velocity restrict and present velocity on the gauge.

Vehicles don’t get pleasure from rails for information transmission, so the Grey and Wilson recreated the performance by utilizing an Arduino to emulate the suitable sign for the ATC unit to learn. It has to speak two information streams to the ATC unit: the velocity restrict and the automobile’s present velocity. The unit has a reasonably standard-looking speedometer for the latter and makes use of small lights at intervals to point the previous.

Grey and Wilson used a laptop computer with OpenStreetMap and the present GPS location to search out the velocity restrict of the highway their automobile is on. It then tells the Arduino to set the corresponding velocity restrict gentle. The speedometer performance, surprisingly, proved to be tougher. The unique plan was to make use of a Bluetooth OBD2 reader to tug the knowledge straight from the automobile, however the adapter was very unreliable. They then tried to estimate the velocity utilizing GPS readings, however that was additionally unreliable and they also returned to the OB2 adapter.

This isn’t dependable or sensible by any means, however it is extremely cool to see the outdated ATC unit working inside a automobile.