I want to make a simple collision detection circuit but the issue is very limited space to place the components, plus it needs to run off of a 1.5v battery...
I have a model train setup around my basement, roughly 110’ of track and a battery powered train runs on the track. The train uses a 1.5v battery powering a standard 1.5-3v electric motor (the kind typically found in cheap toy cars). I was thinking about putting a second train on the track system since it is so long and allow both trains to run at the same time. Inevitably even two identical trains would eventually collide given enough time.
Is there any feasible way to use, say, an IR-LED and photo transistor/diode to simply break the circuit to the motor if the train comes too close to the other? The issue is I only have 1.5v to work with and essentially no room for a microcontroller. I could theoretically stuff a few components smaller than, say a TIP102 transistor into the second empty train car and connect them all directly with soldered wire, but that is about the extent of the space I would have since these cars are HO scale. Adding a second battery or heavier (and higher voltage) power source is not an option due to size and weight.