A small, battery-powered IoT device that detects the presence, absence, or movement of a magnetic field and transmits that data via BLE. This is the dry definition, but there is a bit more depth to this story. Firstly, magnetic sensors are a cheaper option than motion sensors. The combination of BLE (Bluetooth low energy) and magnetics uses very little battery power and they do not need the internet for data transmission.
We have already looked at BLE in previous posts and regard it highly for short range communication… but in combination with magnetic sensors, the two technologies breed new synergies. Obviously, theft and access control because they offer tamper detection. Physical changes register, lending to their common use for window and door alarms in domestic and industrial settings.
A few more unusual examples are in museums and libraries where moving, or touching, an exhibit can activate on screen montages or explainer videos on connected devices. They can verify whether waste collectors actually emptied the bins, as scheduled. If you ever had a flip phone, a magnet sensor may have switched the screen off or off.
Due to the robust nature and small size of these sensors, they have a massive array of industrial applications; from automotive ABS to conveyor belt monitoring. The Reed switch was invented in 1922 by professor Valentin Kovalenkov. It was adapted by Bell labs, for telecommunications purposes, as the reed relay, patented in 1941. For domestic uses, you will find magnetic sensors in all kinds of applications, products and processes.
Hall effect -“electricity and magnetism can work together to move objects” – sensors detect magnetic fields and convert that detection into an electrical signal. A reed sensor is mechanical. In the presence of a magnetic field two wires will touch each other and make a circuit, triggering the next event. You will find these sensors deployed in all types of environments, meaning that enclosures and materials can vary, but the basic principle remains a fixture of most of the electronics we use on a daily basis.
