I have an issue when I connect my HMC6352 2-axis sensors to my Mega. Initially, I was getting readings that read anywhere from 0-360 degrees (though non-linearly). Now, I am having this issue where it gets readings of about 54.8 degrees at a starting position. If I rotate it 90 degrees CCW, the angle will start decreasing until get a reading of 36.2 degrees. As I rotate it another 90 degrees in the same direction, the readings will decrease to 34.0 degrees where it starts to increase yet again. As I continue to rotate it CCW, it will continue to increase until it reaches the 270 degree mark when it gets to 71.9 degrees and starts decreasing again. What could be causing the issue? Do I have a bad sensor? Here is the code that I used.
#include <Wire.h>
int HMC6352Address = 0x42;
int slaveAddress; // This is calculated in the setup() function
int ledPin = 13;
boolean ledState = false;
byte headingData[2];
int i, headingValue;
void setup()
{
// Shift the device's documented slave address (0x42) 1 bit right
// This compensates for how the TWI library only wants the
// 7 most significant bits (with the high bit padded with 0)
slaveAddress = HMC6352Address >> 1; // This results in 0x21 as the address to pass to TWI
Serial.begin(9600);
pinMode(ledPin, OUTPUT); // Set the LED pin as output
Wire.begin();
}
void loop()
{
// Flash the LED on pin 13 just to show that something is happening
// Also serves as an indication that we're not "stuck" waiting for TWI data
ledState = !ledState;
if (ledState) {
digitalWrite(ledPin,HIGH);
}
else
{
digitalWrite(ledPin,LOW);
}
// Send a "A" command to the HMC6352
// This requests the current heading data
Wire.beginTransmission(slaveAddress);
Wire.write("A"); // The "Get Data" command
Wire.endTransmission();
delay(10); // The HMC6352 needs at least a 70us (microsecond) delay
// after this command. Using 10ms just makes it safe
// Read the 2 heading bytes, MSB first
// The resulting 16bit word is the compass heading in 10th's of a degree
// For example: a heading of 1345 would be 134.5 degrees
Wire.requestFrom(slaveAddress, 2); // Request the 2 byte heading (MSB comes first)
i = 0;
while(Wire.available() && i < 2)
{
headingData = Wire.read();
* i++;
}
_ headingValue = headingData[0]256 + headingData[1]; // Put the MSB and LSB together_
Serial.print("Current heading: ");
* Serial.print(int (headingValue / 10)); // The whole number part of the heading*
* Serial.print(".");
Serial.print(int (headingValue % 10)); // The fractional part of the heading*
* Serial.println(" degrees");
delay(500);
}
[/sup]*
Thanks everyone.