This was my final project for Harvard's PS70 Intro to Digital Fabrication class. The process is (will be) documented more on my website for that class, but to give a summary: I wanted to create some sort of display that would show the real time locations of the MBTA trains. Originally, I was going to go with simple LEDs, but I was challenged to make the display mechanical :)

The train location data is pulled from the MBTA's API, and the trains are displayed on a laser-cut map of Boston/Cambridge. As you can see, I actually narrowed the scope down to just a few stops on the Red Line (Davis, Porter, Harvard, MIT). I felt I was pressed for time, but it ended up working really well, so I probably could've committed to the whole line or including other lines. Underneath the map, a gantry system moves an electromagnet that powers on and off to slide the trains to their location the map. I figured this was the easiest and most cost-efficient way to move the trains around, since the T isn't exactly known for its speed.

I programmed it using an ESP32, driving the gantry system with timer pulley belts and stepper motors + drivers. Calibration was done with limit switchesThe little train icons are 3d-printed, and they have a magnet press-fit into them. Overall, a super fun project, got to use plenty of the tools I learned throughout the semester (laser cutter, 3d printer, band saw, etc.). I really want to iterate over this project in the future, creating a smaller, cheaper display that actually includes the rest of the map. Maybe I could hang it up or display it in my apartment. From there, maybe I'd look at adding the commuter rail network or buses.

Check out this video below to see it in action!
it might not be done yet, i still need to edit it...