I recently had to build an infrared close proximity sensor that could tell if something was dropped in a parcel delivery drop box. After some searching, I ended up using a microcontroller ... the time ...

The robot uses a whopping 32 IR sensors to follow a black line across a concrete workshop floor, adjusting its path using a steering motor salvaged from a power wheelchair. An Arduino Mega Pro ...

using the average of several measurements, he ends up with a decent result. Happily, [Fernando] has released the code, and it should be easy enough to repurpose it with a more accurate sensor.

Using motion detectors ... using so you can write the code accordingly. PIR Pin “out” connects to Arduino Digital 2 Here is the Arduino code for the Parallax sensor int motion_1 = 2; int ...