Magnetometer Problems

Well, I have been testing the Magnetometer over the last couple of weeks and was hoping to report some success, however there is a basic problem which I cannot resolve.

A typical graph of the output I am getting is shown below.

The approx. 1280mV line is the initial output from the magnetometer which should then change dependent on changes to the magnetic field, however what seems to be happening is the output jumping to 1800mV (and superimposed on this level there does seem to be a fluctuating signal) before being pulled down to the initial output voltage, almost as if the device is being periodically reset and held at the reset voltage.

(The change between 13:30 and 14:00 was me checking the wiring again, switching off and on etc.)

There seems to be no logic to the frequency of these changes. I have checked and double checked all wiring, the circuit board etc. but cannot find any cause for this problem.

Not sure where to go now.

Magnetometer Installed

Dodging the rain over the weekend I installed the Magnetometer in the garden.

The box with the sensor is buried below ground. The reason for this is to minimise the impact of temperature changes. I have found the sensor to be very sensitive to changes. In the garden also tries to distance the sensor from any moving metallic objects which may impact the readings.

The following shows the sensor box in position:

The compass on the box is to ensure there is correct alignment of the sensor along the east - west axis.

The box about to disappear (I did remove the compass before filling in!)

The control box with the processing electronics is mounted on a fence post in a water tight box.

This is connected to a PicoTech Enviromon system in the shed that monitors the output voltage and records the data. Software on the computer produces an updated graph every few minutes.

I will post some sample graphs to show the results. Hopefully this will work.