Problems with GY-271 magnetometer (HMC5883L != QMC5883L)
Posted: Mon Jul 10, 2017 11:36 amI have been trying to get this magnetometer to work - to no avail.
These are the common, cheap HMC5883L magnetometers available on well known reprobate auction sites, I'll post a link if necessary, but I suspect you know the ones - 5 pins: Vcc, Gnd, SCL, SDA and unused DRDY.
I got one module and tried it with NodeMCU/Lua - no luck, it just reported device not found. I then tried with the common Arduino scripts given, no luck here, either, it appeared not to be connecting. I tried with various ESP8266 devices, no difference. Then I assumed the magnetometer was blown so I ordered a couple more, but now that these have arrived, same problem, they just don't seem to register.
I am a newbie to I2C, so I ran the following scan, while having two devices on the bus (the second one was a u8g OLED.:
It found the two devices, reporting thus:
I know that 0x3C is the u8g display, so the HMC5883L is 0xD. I tested three different magnetometers, they all reported the same address (0xD)
Looking through the HMC5833L.h code, I was surprised to see that the hardcoded address for the magnetometer is 0x1E. I tried changing that to 0x0D but still no joy.
In both cases I get the a constant, unchanging value back, although it is different if I change the hardcoded address. The code is a pretty standard example, FWIW here it is...
Using 0x1E
Using 0xD:
Any ideas?
These are the common, cheap HMC5883L magnetometers available on well known reprobate auction sites, I'll post a link if necessary, but I suspect you know the ones - 5 pins: Vcc, Gnd, SCL, SDA and unused DRDY.
I got one module and tried it with NodeMCU/Lua - no luck, it just reported device not found. I then tried with the common Arduino scripts given, no luck here, either, it appeared not to be connecting. I tried with various ESP8266 devices, no difference. Then I assumed the magnetometer was blown so I ordered a couple more, but now that these have arrived, same problem, they just don't seem to register.
I am a newbie to I2C, so I ran the following scan, while having two devices on the bus (the second one was a u8g OLED.:
Code: Select all
#include <Wire.h>
void setup() {
Serial.begin (9600);
// Leonardo: wait for serial port to connect
while (!Serial)
{
}
Serial.println ();
Serial.println ("I2C scanner. Scanning ...");
byte count = 0;
Wire.begin();
for (byte i = 1; i < 120; i++)
{
Wire.beginTransmission (i);
if (Wire.endTransmission () == 0)
{
Serial.print ("Found address: ");
Serial.print (i, DEC);
Serial.print (" (0x");
Serial.print (i, HEX);
Serial.println (")");
count++;
delay (1); // maybe unneeded?
} // end of good response
} // end of for loop
Serial.println ("Done.");
Serial.print ("Found ");
Serial.print (count, DEC);
Serial.println (" device(s).");
} // end of setup
void loop() {}
It found the two devices, reporting thus:
Code: Select all
I2C scanner. Scanning ...
Found address: 13 (0xD)
Found address: 60 (0x3C)
Done.
Found 2 device(s).
I know that 0x3C is the u8g display, so the HMC5883L is 0xD. I tested three different magnetometers, they all reported the same address (0xD)
Looking through the HMC5833L.h code, I was surprised to see that the hardcoded address for the magnetometer is 0x1E. I tried changing that to 0x0D but still no joy.
In both cases I get the a constant, unchanging value back, although it is different if I change the hardcoded address. The code is a pretty standard example, FWIW here it is...
Code: Select all
// Reference the I2C Library
#include <Wire.h>
// Reference the HMC5883L Compass Library
#include <HMC5883L.h>
// Store our compass as an object.
HMC5883L compass;
// Record any errors that may occur in the compass.
int error = 0;
// Out setup routine, here we will configure the microcontroller and compass.
void setup()
{
Wire.begin(); // Start the I2C interface.
// Initialize the serial port.
Serial.begin(9600);
Serial.println("Starting the I2C interface.");
Serial.println("Constructing new HMC5883L");
compass = HMC5883L(); // Construct a new HMC5883 compass.
//The implementation of the class is provided in the library
// Now we have an istance of the class!
//Let's initializate it...
// Now we have an istance of the class!
//Let's initializate it...
Serial.println("Setting scale to +/- 1.3 Ga");
error = compass.SetScale(1.3); // Set the scale of the compass to 1.3Ga
if(error != 0){ // If there is an error, print it out.
Serial.println(compass.GetErrorText(error));
error =0;
}
Serial.println("Setting measurement mode to continous.");
error = compass.SetMeasurementMode(Measurement_Continuous); // Set the measurement mode to Continuous
if(error != 0) {// If there is an error, print it out.
Serial.println(compass.GetErrorText(error)); //Todo: Error handling for this method in .h and .cpp
error=0;
}
//=======================================
// AG - extra connection check
Serial.print("Checking connection... ");
error = compass.EnsureConnected();
if(error == 0) {
Serial.println("Not Connected");}
else {
Serial.println(" Connected");}
error =0;
}
// Our main program loop.
void loop()
{
// Retrieve the raw values from the magnetometer (not scaled).
MagnetometerRaw raw = compass.ReadRawAxis();
// Retrieve the scaled values from the magnetometer (scaled to the configured scale).
MagnetometerScaled scaled = compass.ReadScaledAxis();
// Values are accessed like so:
int MilliGauss_OnThe_XAxis = scaled.XAxis;// (or YAxis, or ZAxis)
// Calculate heading when the magnetometer is level, then correct for signs of axis.
// Atan2() automatically check the correct formula taking care of the quadrant you are in
float heading = atan2(scaled.YAxis, scaled.XAxis);
// Once you have your heading, you must then add your 'Declination Angle',
// which is the 'Error' of the magnetic field in your location. Mine is 0.0404
// Find yours here: http://www.magnetic-declination.com/
// If you cannot find your Declination, comment out these two lines, your compass will be slightly off.
float declinationAngle = 0.0404;
heading += declinationAngle;
// Correct for when signs are reversed.
if(heading < 0)
heading += 2*PI;
// Check for wrap due to addition of declination.
if(heading > 2*PI)
heading -= 2*PI;
// Convert radians to degrees for readability.
float headingDegrees = heading * 180/M_PI;
// Output the data via the serial port.
Output(raw, scaled, heading, headingDegrees);
// By default the HMC5883L reads the data 15 time per second (15Hz)
// However since we have a long serial out (104ms at 9600) we will let
// it run at its natural speed.
delay(2000);
}
// Output the data down the serial port.
void Output(MagnetometerRaw raw, MagnetometerScaled scaled, float heading, float headingDegrees)
{
Serial.print("Raw:\t");
Serial.print(raw.XAxis);
Serial.print(" ");
Serial.print(raw.YAxis);
Serial.print(" ");
Serial.print(raw.ZAxis);
Serial.print(" \tScaled:\t");
Serial.print(scaled.XAxis);
Serial.print(" ");
Serial.print(scaled.YAxis);
Serial.print(" ");
Serial.print(scaled.ZAxis);
Serial.print(" \tHeading:\t");
Serial.print(heading);
Serial.print(" Radians \t");
Serial.print(headingDegrees);
Serial.println(" Degrees \t");
}
Using 0x1E
Code: Select all
Starting the I2C interface.
Constructing new HMC5883L
Setting scale to +/- 1.3 Ga
Setting measurement mode to continous.
Checking connection... Not Connected
Raw: 256 0 0 Scaled: 235.52 60041.96 0.00 Heading: 1.61 Radians 92.09 Degrees
Raw: 44677 0 65087 Scaled: 235.52 235.52 0.00 Heading: 0.83 Radians 47.31 Degrees
Raw: 44677 0 65087 Scaled: 235.52 235.52 0.00 Heading: 0.83 Radians 47.31 Degrees
Raw: 44677 0 65087 Scaled: 235.52 235.52 0.00 Heading: 0.83 Radians 47.31 Degrees
Using 0xD:
Code: Select all
Starting the I2C interface.
Constructing new HMC5883L
Setting scale to +/- 1.3 Ga
Setting measurement mode to continous.
Checking connection... Not Connected
Raw: 0 0 0 Scaled: 0.00 0.00 0.00 Heading: 0.04 Radians 2.31 Degrees
Raw: 0 0 0 Scaled: 0.00 0.00 0.00 Heading: 0.04 Radians 2.31 Degrees
Raw: 0 0 0 Scaled: 0.00 0.00 0.00 Heading: 0.04 Radians 2.31 Degrees
Any ideas?
I found out the following: