Home Sensor Projects Connecting a MLX90393 magnetic field sensor to an Arduino Uno

Connecting a MLX90393 magnetic field sensor to an Arduino Uno

by shedboy71

The MLX90393 magnetic field sensor is designed for micropower applications, with programmable duty cycles in the range of 0.1% to 100%.

The MLX90393 magnetic field sensor can be reprogrammed to different modes and with different settings at run-time. The sensor offers a 16-bit output proportional to the magnetic flux density sensed along the XYZ axes using the Melexis proprietary Triaxis® technology and also offers a temperature output signal. These digital values are available via I2C and SPI, where the MLX90393 is a slave on the bus.

By selecting which axes are to be measured, the raw data can be used as input for further post-processing, such as for joystick applications, rotary knobs, and more complex 3D position sensing applications.

Once again you would typically purchase a module like the following one

 

Connection

This is an I2C device which uses 3.3v – so make sure you power the module correctly

Module Arduino Uno
VDD 3v3
Gnd Gnd
SDA SDA – A4
SCL SCL – A5

Code

 

No libraries needed, the code below was found in github – I like it as it shows the I2C functions

// Distributed with a free-will license.
// Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
// MLX90393
// This code is designed to work with the MLX90393_I2CS I2C Mini Module available from ControlEverything.com.
// https://www.controleverything.com/products
 
#include<Wire.h>
 
// MLX90393 I2C Address is 0x0C(12)
#define Addr 0x0C
 
void setup()
{
// Initialise I2C communication as MASTER
Wire.begin();
// Initialise serial communication, set baud rate = 9600
Serial.begin(9600);
 
// Start I2C Transmission
Wire.beginTransmission(Addr);
// Select Write register command
Wire.write(0x60);
// Set AH = 0x00, BIST disabled
Wire.write(0x00);
// Set AL = 0x5C, Hall plate spinning rate = DEFAULT, GAIN_SEL = 5
Wire.write(0x5C);
// Select address register, (0x00 << 2)
Wire.write(0x00);
// Stop I2C Transmission
Wire.endTransmission();
 
// Request 1 byte of data
Wire.requestFrom(Addr, 1);
 
// Read status byte
if(Wire.available() == 1)
{
unsigned int c = Wire.read();
}
 
// Start I2C Transmission
Wire.beginTransmission(Addr);
// Select Write register command
Wire.write(0x60);
// Set AH = 0x02
Wire.write(0x02);
// Set AL = 0xB4, RES for magnetic measurement = 0
Wire.write(0xB4);
// Select address register, (0x02 << 2)
Wire.write(0x08);
// Stop I2C Transmission
Wire.endTransmission();
 
// Request 1 byte of data
Wire.requestFrom(Addr, 1);
 
// Read status byte
if(Wire.available() == 1)
{
unsigned int c = Wire.read();
}
delay(300);
}
 
void loop()
{
unsigned int data[7];
 
// Start I2C Transmission
Wire.beginTransmission(Addr);
// Start single meaurement mode, ZYX enabled
Wire.write(0x3E);
// Stop I2C Transmission
Wire.endTransmission();
 
// Request 1 byte of data
Wire.requestFrom(Addr, 1);
 
// Read status byte
if(Wire.available() == 1)
{
unsigned int c = Wire.read();
}
delay(100);
 
// Start I2C Transmission
Wire.beginTransmission(Addr);
// Send read measurement command, ZYX enabled
Wire.write(0x4E);
// Stop I2C Transmission
Wire.endTransmission();
 
// Request 7 bytes of data
Wire.requestFrom(Addr, 7);
 
// Read 7 bytes of data
// status, xMag msb, xMag lsb, yMag msb, yMag lsb, zMag msb, zMag lsb
if(Wire.available() == 7);
{
data[0] = Wire.read();
data[1] = Wire.read();
data[2] = Wire.read();
data[3] = Wire.read();
data[4] = Wire.read();
data[5] = Wire.read();
data[6] = Wire.read();
}
 
// Convert the data
int xMag = data[1] * 256 + data[2];
int yMag = data[3] * 256 + data[4];
int zMag = data[5] * 256 + data[6];
 
// Output data to serial monitor
Serial.print("Magnetic Field in X-Axis : ");
Serial.println(xMag);
Serial.print("Magnetic Field in Y-Axis : ");
Serial.println(yMag);
Serial.print("Magnetic Field in Z-Axis : ");
Serial.println(zMag);
delay(500);
}

 

 

 

Output

Open the serial monitor and you should see output like this

Magnetic Field in X-Axis : 66
Magnetic Field in Y-Axis : 65458
Magnetic Field in Z-Axis : 8
Magnetic Field in X-Axis : 83
Magnetic Field in Y-Axis : 65477
Magnetic Field in Z-Axis : 65525
Magnetic Field in X-Axis : 76
Magnetic Field in Y-Axis : 65452
Magnetic Field in Z-Axis : 65506
Magnetic Field in X-Axis : 25
Magnetic Field in Y-Axis : 65374
Magnetic Field in Z-Axis : 65512

 

Links

https://www.melexis.com/-/media/files/documents/datasheets/mlx90393-datasheet-melexis.pdf

CJMCU-90393, MLX90393 digital 3D Holzer sensor, displacement, angle, rotation, 3D position

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