COLUMN Vol.5 The innovation of the Hall Effect Switch IC causing a revolution to IoT devices

Overcoming the limitations of Hall Effect Switch ICs

In our previous column, we explained how Hall Effect Switch ICs are effective as a technology for detecting changes in the movement or status of things, and how they detect magnetic fields and convert them to electrical signals.
However, there has been a limit to what conventional Hall Effect Switch ICs can do. That is, they can only distinguish two states.
For example, the unipolar detection Hall Effect Switch ICs described in the previous article are fixed to detect an N pole or an S pole. So, they can only detect the presence or absence of an N pole or S pole. In the same way, an omnipolar detection Hall Effect Switch IC can only distinguish two states.
The S-5718 series overcomes that limitation of Hall Effect Switch ICs.
This S-5718 series ICs are able to switch the detecting pole according to the input signal so as to detect N poles, S poles, and both poles. (Please see the sidebar at the end of this article entitled, "The S-5718 Series: Overview of the Mechanism.") In other words, the S-5718 series makes it possible to distinguish three states with a single IC: a N pole in proximity, a S pole in proximity, and no magnet.

The operation detection mechanism is simpler

So, what changes specifically with the S-5718 series that can distinguish three states?
The first thing that can be said is fewer Hall Effect Switch ICs will be needed to distinguish various operations and the states of things.
For instance, think about a 2-in-1 PC. These PCs have three states: A closed state, an open state, and a tablet mode. If Hall Effect Switch ICs that can only distinguish two states are used in this case, then at least one magnet and two Hall Effect Switch ICs would be necessary. However, if the S-5718 series is used, then one magnet and one Hall Effect Switch IC can distinguish all three states.
When designing and developing home appliances, toys, wearable or other products, there are sure to be instances when it would be better if the operation or sound effects of the main unit changed according to the attachments used.
If the S-5718 series is used in such cases, then a system can be made in which more attachments can be distinguished with fewer Hall Effect Switch ICs. In fact, if two S-5718 series ICs are used then nine (3 x 3) different states can be distinguished, and if three are used then 27 (3 x 3 x 3) different states can be distinguished. (If "no magnet" is counted as one state for each IC.)

Expanding the possibilities of IoT devices

Using the S-5718 series should greatly expand the possibilities in designing and developing IoT devices.
For instance, let us say that you have made a greenhouse for growing vegetables that have an opening/closing module built into the windows and that those modules are connected to the Internet with Wi-Fi to output the opened/closed state. Consider that you have developed an IoT application that uses a smartphone to remotely control them. In this case, a need to adjust the window openings depending on the day's temperature and sunlight is sure to develop.
In such a case, if the S-5718 series is used whereas it is possible to easily design an open/close module that can control the angle of the windows for closed, slightly opened, and fully opened. In a similar way, the same system could be applied to control the blinds of a house, hospital or business in three states depending on the sunlight.
A security system to monitor the opened/closed states of patient room doors could be made to distinguish three states instead of just closed or opened states and send alerts. Before a door is opened so that a person can pass through, an alert could be sent to the smartphones of the nurses over Wi-Fi or Bluetooth. This could give the nurses a little more time to get to the room.

In addition to being able to distinguish three different states, the S-5718 series has greatly reduced the minimum operating voltage to 1.45 volts from the conventional 1.6 volts. Additionally, the S-5718 series, similarly to the conventional Hall Effect Switch ICs developed by ABLIC, has achieved the high-density mounting that is the best in the industry. The SNT-4A package (4-pin, 1.6 x 1.2 x 0.5 mm) has been adopted. From these points of view, it can be said that these Hall Effect Switch ICs are perfect for IoT devices that require power and space saving.

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