40PCS A3144 3144 Hall Effect Sensor Magnetic Detector 3Pins A3144 TO-92UA Hall Sensor for Arduino...

This was my first time using hall-effect sensors, but I wanted something that could sense a magnet to form a crude encoder in a hobby robotics project. While I initially had some difficulty, it turned out that I had the device turned backwards. For reference, the standard pinout is correct relative to the printed face, which is also the smaller of the two flat faces. Anyhow, once that was established, and I got a 10k pullup resistor across the VCC/Signal pins, I was able to read the sensor using an Arduino's digitalRead(). The signal seemed clean, and was sensitive to both small neodymium and larger ferrite magnets at about a 1.5cm range. A flat kitchen magnet (i.e., the decorative kind) only triggered the device when physically touching it, but I was able to see that the polarity of the magnet flip-flopped every few mm, by sliding the magnet across the hall sensor. All told, I'm excited to have a new tool in the toolbox!

These A3144 digital hall effect sensors act more like switches, but they work. I had to do a little digging to find a datasheet that listed the sensitivity thresholds that determine when they switch to HIGH or LOW. We use them with an Arduino R3 without issue, and you get plenty (40) to play with.

Just what I ordered. Have not put any of the product into service, yet.

As advertised!

Simple to implement into projects. Great price.