Magnetometer / Magnet sensor

Sensor description

It's a localized magnetic field detector to be used with a small magnet. It does not measure Earth's magnetic field (like a compass would).

Magnet detector

It is a proximity sensor using the Hall effect. Its range is about 3 cm with our smallest magnets. Range can be increased by using a stronger magnet.

Data returned by the sensor over time

Video

Application example

Magnetic sensor by Interface-z

Proximity / distance

This sensor lets one detect the proximity between two objects, the one hiding a magnet, the other hiding the sensor. The objects can be part of an interactive installation or a set decor.

If a sensor is hidden in a table, the magnet equipped to an object, the table then detects if the object is put down on it or picked up, and even the objects orientation on it.

Wheels and turn-counting

One of the practical adaptations of this sensor is to make it into a turn-counter : If one wishes to analyse the movement of a rotating object (upon which one wasn't able to equip a potentiometer), the magnet sensor can be very helpful.
One just needs to fasten the sensor to a fixed object closeby, and a magnet on the object that is turning.
Each turn the magnet approaches and then moves away from the sensor, creating a very recognizable signal pattern. Turn counting can then be intrerpreted into information about the rotation speed, and rotation direction.

Caracteristics

Magnet detector with its magnet

- The signal is analog, it varies with the distance of the magnet and its polarity. The magnet's north pole will modify the data values in one way, the south pole in another way (one pole might increase the data value, and the other decrease it).

- The sensor has two settings : gain (sensitivity amplification) and rest value (zero level), which lets the sensor be adapted to different situations. The adjustment of the rest value (zero level) lets one perceive the polarity of the approaching magnet, or setting the rest value towards one limit of the value range (0 or maximum)

- Provided magnet size : d 8 mm x 1,8 mm thickness .

Settings direction

Magnets

Magnets can have different sizes and attraction strengths.

We automatically provide a small disk-shaped dark grey magnet, dimensions : 1,15 cm x 0,8 cm x 0,7 cm.

Upon request we can provide other magnets, some of them stronger, such as our cubic magnets or mini disk magnet. Both of these are colored in shiny silver.