“We could automatically detect whether the racing mower is about to run out of fuel by shining a light through a section of clear fuel hose with a sensor on the other side. The idea is that when the fuel has disappeared the received light intensity will change, and we can detect this with a microcontroller. We can then turn on an LED on the dashboard to alert the driver so that he makes a pit stop instead of spluttering to a halt at the opposite end of the track.
If you want to see a video of it in action, I have this video but it’s not a very good video.
You can get the Arduino code and housing CAD files on my github project.
This is a good design for the fuel sensor, in my opinion, because the fuel is entirely contained within off-the-shelf parts that are designed to contain fuel and never touches any custom parts, which means the chances of causing a leak or fire are low. The bad part about this design is that it does not give us an easy way to configure a threshold at which the warning light comes on: it just comes on once the fuel level has dropped below the position of the sensor. But I think this should still give us a lap or two of warning, because we still have the fuel in the rest of the hose, the fuel filter, and the float bowl.”