Hey Kai, Sorry, I don't have any schematics available, but the two things I needed to get GPIO working were using a common ground between the PI and the LED sensor, and ensuring the resistance between the LED and the GPIO was within an acceptable range. Initially I had too much resistance and didn't...

Hi Tim, Yes, hardware for the prototype is working well, I ended up subverting an LED on the master IR sensor to act as the GPIO trigger event. Here's a photo of the set up, the PV panel is hidden under the rpi and batteries, and it's hooked up via ethernet instead wifi as my adapter died and still ...

Hello again, I ended up buying an active infra-red sensor similar to PiGraham's suggestion, and although the manual translation from Chinese to English was more humorous than helpful, it appears to be working well. When I measure the voltage on the comms line which linked the two sensors (called mas...

I'm not sure an IR motion detector will react to a cyclist speeding past. You'll need to test that out. Other possibilities (among many I'm sure) are a pressure sensor on the track or interrupting a light beam. I did consider a pressure sensor, but a pump track is made up of rollers (like a sine wa...

I don't think PIR is the right sensing technology for this. If you want accurate timing you should use a through-beam sensor that triggers on the wheel. The PIR will only register the rider, and not very precisely. Check what the response time is. Ahh, good point, I dug through the specs and the sl...

Of course just after posting I found a nice tutorial on Adafruit

The only issue I can see is that PIR sensor as a 120º spread, whereas I'm probably looking for something more narrow, but that could be reduced by enclosing in a tube or similar.

Greetings, Seeking advice on a suitable sensor to interface with a raspberry pi for use as a lap timer for a bike pump track. Ideally the sensor should detect when the tyre breaks the beam, but rider detection is ok so long as it's reasonably consistent. Google has turned up this PIR , but I'm an el...