At Sensors Expo 2019, Eduardo Montalvo, an application engineer from Coto Technology, explains a RedRock demo board with the different output responses provided by his company’s sensors. RedRock’s tunneling magnetoresistance (TMR) technology can provide both analog and outputs based on the magnetic field. The sensors can be used for proximity detection or position detection such as tracking the position of a float in liquid level sensing and other applications.

An omnipolar sensor can turn on an LED on the demo board by bringing either pole of a magnet within triggering distance. With a dual unipolar sensor, one output can be turned on with one polarity and the other is turned on with the opposite polarity. A bipolar sensor provides a latching response turning on the LED when it comes within the proper range and the LED stays on until the opposite polarity is similarly applied. Finally, the analog sensor provides an analog voltage output proportional to the magnetic field that it experiences.

The specifications of the different types of magnetic sensors are shown on the company’s website. Key specifications for the TMR sensors include operating and release sensitivities in gauss (G), frequency that can range from 2 to 10,000 or continuous depending on the type of output, temperature rating that is either -40 to 85°C or -40 to 125°C, output response and package type.

For interested potential users, the RR1EK2-0001 Evaluation Board provides users the capability of evaluating both an analog sensor and a digital switch with a supplied cylindrical magnet.