Designing and Building a Custom Optical Fuel Sensor

Designing and Building a Custom Optical Fuel Sensor

At some time or another, we’ve all had an idea we thought was so clever that we jumped on the Internet to see if somebody else had already come up with it. Most of the time, they have. But on the off chance that you can’t find any signs of it online, you’re left with basically two possible conclusions. Either you’re about to enter uncharted territory, or your idea is so bad that everyone has collectively dismissed it already.


Which is precisely where [James Stanley] recently found himself. He had an idea for an non-contact optical sensor which would detect when his racing mower was about to run out of gas by analyzing light passed through a clear section of fuel hose. He couldn’t find any previous DIY examples of such a device, nor did there appear to be a commercial version. But did that mean it wouldn’t work, or that nobody had ever tried before?


Sensor proof of concept

Before he fully committed to designing the sensor, [James] started out by doing some proof of concept experiments. The first step was 3D printing a ring that had openings to slot in a LED and photoresistor at different angles to each other. Putting the LED and sensor on opposite sides of the fuel line makes the most logical sense, but he wanted to test if it really returned the strongest signal. Surprisingly this little test indicated that the best alignment was actually 60°, as it produced the largest gap between the “fuel” and “no fuel” readings.


Confident that the idea had merit, [James] pushed ahead a ..

Support the originator by clicking the read the rest link below.