COLUMN Vol.4 Motion Detection with Hall Effect Switch ICs

The limits of physical switches and optical sensors

Detecting the movement of things such as home windows and doors and then converting them to electrical signals traditionally has been done with mechanical switches.

However, in order for a physical switch to detect the opening and closing movement of a window or door, the construction becomes complicated because the switch requires a pressing movement or a sliding movement. Furthermore, if dust accumulates around the moving section or the unit becomes exposed to moisture, then it can easily fail and there is no assurance that it will be stable for long periods of time.

So, what about non-contact switches made by combining light-emitting diodes with optical sensors? This mechanism would make the physical construction simple and facilitate design. However, there is the concern that ambient light and grime could reduce the sensitivity of the sensors. In this case, It is also difficult to reduce power consumption.

Hall Effect Switch IC as an option

Hall Effect Switch IC's are a technology that can solve all of the technological problems described above. The Hall Effect Switch IC is an IC that uses semiconductor sensors to convert magnetic strength into electrical signals. There are three types of magnetic detection: Unipolar detection, omnipolar detection, and alternate detection. Hall Effect Switch ICs that use these methods have the characteristics described below.

(1) Unipolar detection/omnipolar detection

Unipolar detection/omnipolar detection Hall Effect Switch ICs are switch type ICs that detect the proximity of magnets and output signals. When the magnets move away, they return to their original states. Unipolar detection units react to either the N or S poles, and omnipolar detection units react to both.
These types of Hall Effect Switch ICs can be used together with magnets as non-contact switches. Therefore, they are widely used to detect the opened or closed state of flip phones and laptop computers.
For example, a small magnet can be placed on the screen side of a mobile phone, and a Hall Effect Switch IC on the keypad side. When the user closes the phone, the Hall Effect Switch IC detects the proximity of the magnet, it then outputs a signal, and puts the cell phone into sleep mode.

(2) Alternate detection

Alternate detection Hall Effect Switch ICs detect when the N and S poles alternate. Also known as bipolar detection.
For instance, a circular magnet is rotated, and an alternate detection Hall Effect Switch IC is placed near it. This allows measurement of the rotational speed of the circular magnet. This type of Hall Effect Switch IC is used to control the rotational speed of motors and fans.

A wide variety of Hall Effect Switch ICs
Making the wishes of engineers into something tangible

As the descriptions above show, the concept behind Hall Effect Switch ICs are very simple. They can be applied to many different magnetic sensing transistions and functions.

Therefore, ABLIC provides many different types of Hall Effect Switch ICs to meet the needs of engineering challenges. Today, we are expanding the range of our Hall Effect Switch ICs for applications in the IoT world, such as Hall Effect Switch ICs of low-voltage type, high breakdown voltage type, high-speed operation, and high-temperature operation type.

The Hall Effect Switch ICs from ABLIC also have the common features of being compact, low power, highly accurate, and high in quality. With respect to power consumption, they rate among the lowest in the industry. Package mounting density is among the best in the industry. We have many different models available centering on our non-leaded SNT-4A (4-pin, 1.6 x 1.2 x 0.5 mm) that simplifies visual inspections. Our general-purpose SOT-23-3 and SOT-23-3S units.
Oftentimes, IoT devices are required to be durable, energy efficient and space saving. It can be said that the Hall Effect Switch ICs from ABLIC are perfect for use in such IoT devices.

ABLIC provides a variety of technological support services for Hall Effect Switch ICs including our High-precision Magnetic Simulation Service. This service allows an inexperienced person dealing with magnetism, magnets and Hall Effect Switch ICs to make highly accurate magnetic designs.