2PCS DC5-30V NJK-5002C 10mm Hall Effect Switch Proximity Sensor Inductive Switch NPN NO (Normally Open)

Very pleased with my purchase. Using them as non-contact end switches for a robot. They work very well with an arduino.

The diagram on the sticker (attached to the cord) doesn't match how it functions. After getting the LED indicator to light (and change when a magnet is near), it seems there's only a tiny spot about 7mm down one side that actually triggers the sensor. When triggered, it only closes the circuit around 5-10% of the time (and that's with the understanding that hall effect sensors do need a magnet, not 'metal' as described). My best guess is that it needs more than the max of 5V+20mA an arduino can deliver, even though it lists 5V within the spec and only a max current.

Ordered 2 sets ( 4 sensors) 2 of the 4 didnt work at all. (More chinese junk from amazon) would have returned but needed the ones that worked and had to cut wire to fit. My loss amazons gain, again.

only works on the side for some reason. like some of the other comments, it may need more power or it is deffective. The only way i was able to make this work was with a magnet running it up and down the side of the threads. the tip of the sensor does not work at all.

Product works well as described. The sensor is made in Taiwan, not in China.

Not as described, needs magnet. Also only got 1 magnet, and two sensors. I sensor did not work right out of the box.

The description states that this unit detects metal, however through my own testing I've found that this device will only detect a magnet. So it will work as described apart from the detectable material, which in this case is only magnetic materials. It cannot detect metal of any kind!! One star because the description is false.