The TMR mix-sens Click is an add-on board equipped with the TMR digital push-pull and analog magnetic sensors, as well as intensity of magnetic field indicator. The TMR mix-sens Click has three types of magnetic field sensors: Two digital and one analog sensor. The digital sensors are the RR121-1A23-311 which has an omnipolar polarity response, and the RR121-3C63-311 which has a bipolar polarity response. The analog sensor is the RR111-1DC2-331, which outputs a voltage that is proportional to magnetic field. The board also has an LM3914 voltage level indicator, which takes the output voltage of the RR111-1DC2-331 sensor and uses it to light a series of LEDs to indicate the level of magnetic field seen by the sensor. All sensor outputs can be accessed through mikroBUS I/O or analog pins, also they are visually represented over on-board LED's. This board can be used for evaluation of the TMR sensors as well as for testing applications which are requiring low power wake up functionality.

TMR mix-sens Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

TMR mix-sens Click provides three different Coto Technology RedRock™ TMR magnetic sensors that can be operated with supplied magnets and provide instantaneous visual feedback through LED's that indicate sensor output. These sensors utilize tunneling Magnetoresistance (TMR) technology that provides the lowest power consumption and highest magnetic sensitivity of any available magnetic sensor. With the board you will also receive cylindrical magnets for performing out of the box testing. To get started, you’ll need to supply 3.3V and 5V to the corresponding pins.

The first sensor on this Click board™, a Coto Technology RedRock RR121-1A23-311 is an ominpolar, 9 Gauss operate, 10Hz sensing frequency, push pull output sensor that consumes an average of only 240nA. This sensor is often used for proximity detection or as a means to signal a battery operated device to wake up or power on. The second sensor on this Click board™ is an RR121-3C63-311 which is a bi-polar, 10 Gauss operate/-10 Gauss release, 500Hz sensing frequency, push pull output sensor that consumes an average of 1.7uA. This sensor is often used for rotation counting. The third sensor on this Click board™ is an RR111-1DC2-331 which provides a linear voltage output that is proportional to a magnetic field strength between -10 and 10 Gauss with a sensitivity of -20 mv/V/G and 1.5mA average supply current. This sensor is typically used in level or distance sensing applications and can provide a distance resolution of 1mm.

In addition to being able to access the outputs of the three sensors through the mikroBUS and get information to the host MCU, a visual confirmation of the activation and deactivation of each sensor is provided by means of LEDs placed next to each of the sensors on the board. When operating these sensors with the supplied magnets or magnets of your choosing, the LED's associated with each sensor will activate to visually indicate the sensing of a magnetic field. The LED2 for the RR121-1A23-311 lights up when the operate field strength of 9 Gauss is reached and subsequently turns off when the release field strength of 5 Gauss is reached, providing a hysteresis of 4 Gauss. This can demonstrated by moving the North or South pole of magnet towards the sensor in the direction of the arrow. The LED3 for the RR121-3C63-311 lights up when a South pole field with a magnitude of 10 Gauss or greater is sensed and will stay lit until a North pole of 10 Gauss or higher is sensed. This can be demonstrated by bring in a magnet with one polarity and then reversing it. It can also be demonstrated by rotating the supplied ring magnet in the hole adjacent to the sensor.

The semi-circular array of nine LEDs (LED4-LED12) on the top of the board are used for the RR111-1DC2-331 sensor. Please refer to the image above for the LED numbering. These will light to indicate when the sensor sees a North field, a South field or no field, and the magnitude for each polarity. The middle LED (LD8) will light to indicate no magnetic field (voltage output of Vdd/2). An LM3914 is used for indicating strength of linear output of RR111-1DC2-331 sensor. The operation of this sensor can be demonstrated by moving the North of South pole of the magnet towards the sensor in the direction of the magnet. Alternatively, it can be demonstrated by rotating the ring magnet in the hole adjacent to the sensor.

Holes on the TMR mix-sens Click can be used to ease the installation of rotatable magnet holders.

• Interface: Analog, GPIO
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V, 5V

• Schematic
• RR111TMR Datasheet
• RR121TMR Datasheet
• LM3914 Datahseet
• mikroSDK
• GitHub