ESP8266 Community Forum

Looking to use the KY-003 Hall Magnetic Sensor Module with my NodeMCU need help with both hardware and software.
The idea is to have the sensor connected to the power cord and sensing the magnetic field created when current is present thereby signaling "ON" and when power is not present signal "OFF" will incorporate ITTT to send cell phone status.

Any information on the creation is well appreciated.

As far as I remember, KY-003 module is based on a Allegro A3144 hall effect sensor that has a working voltage of about 4.5V-24V, will not work directly on 3.3V, you need a voltage level translator.

A3144 has :
- Operate point (G) - 35 to 450
- Release point (G) - 25 to 430

I don't know if that Hall sensor is sensible ennough to sense the power line switching.

For things like that usually you use a optocoupler or a CT transformer, both more reliable than the hall sensor setup. And If you need only ON/OFF sensing, a simple optocoupler setup will be more than enough.

I got one of these in a set of sensor modules I bought on eBay. The only documentation I could find is here https://tkkrlab.nl/wiki/Arduino_KY-003_ ... sor_module.