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 and a piece ...

Hello everyone! Today I’m going to discuss a cheap type of useful digital rotation per minute counter (Digital RPM Counter). The 4-Digit LED Display RPM comes with a magnetic proximity sensor switch.

[Dustin Andrews] built this add-on board which works as a proximity sensor. He wanted a standalone sensor for his Arduino projects which would use a single pin as a trigger. This lets him alert the ...

Getting a magnetic field to balance on another magnetic field is about as easy as balancing a bowling ball on the tip of an ink pen. With a little help from an Arduino mega, however, [EmmaSong] was ...