Template:PTX COMPASSCAL

Magnetometer Calibration

Magnetometer Calibration Guide

In order to get accurate results from your spatial's compass you will need to provide calibration parameters.

Follow this guide to complete the calibration process.

1. Open the Phidget Control Panel and right click on your Spatial Phidget. Select Calibrate Magnetometer.

2. Go to the webpage listed in the window that opens (or click this link):

http://www.ngdc.noaa.gov/geomag-web/#igrfwmm

3. Enter your full address including postal code and click Get & Add Lat / Lon.

This will cause numbers to appear in the left section. Click Calculate.

4. Grab the Total Field value from the window that pops up and convert it from nT to G by dividing by 10000. Put the new gauss value into the Local Field Strength field in the Magnetometer Calibrator.

5. Make sure your Phidget Spatial is firmly in the position you intend to calibrate it for, and begin by clicking the Start button.

6. Rotate the Phidget around so that the graph on screen begins to draw a complete sphere. This will take a few minutes. Don't worry if the result doesn't look like a perfect sphere, just try to rotate the Phidget in a way that fills in as much of the empty regions as possible. If the Phidget is mounted in a vehicle, drive it around and the calibrator will fill out a flat circle instead of a sphere.

When you're finished, click Stop.

7. The calibration is now complete. Calibration values have been saved to the on-board flash memory, so it'll remember this calibration even if the device is unplugged.

You can find the calibration parameters in the text box in case you want to quickly recalibrate this Phidget or calibrate a replacement that will sit in the same installation. You can use these values in the setMagnetometerCorrectionParameters method. See our API Documentation for more details.

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