FGM-3

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Once upon a time I've decided to built 3-axis fluxgate magnetometer. The main problem were money(there are some cool 3-axis fluxgate magnetometers such as FL3-100, but it costs 1600$). So now I have 3 FGM-3 sensors. I whant to make 3-axis orthogonal system using them(of course we will have some orthogonal errors). The problem is signal processig unit. The SCL006 chip is good but a refresh rate of it is only 8 seconds and also some errors take place. Another decision is using LM2917 frequency to voltage converter with heteterodyn, but here we have another problem: detecting only positive fields. I think the better choise is microcontroller, using some technics we can recieve good linear response and a good refresh rate for 3 sensors.

I will be thankful for any ideas, opinions or advices about FGM-3.

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As soon as I can get 4 x FGM-3 (there not that high on my wish list) I’m planning a (single or dual mode) Gradiometer plus logger and I’ll be going the microcontroller route.

Using LM2917 frequency to voltage converter would mean going: digital -> analogue ->digital, seems a bit weird to me.

The SCL006 chip is just a Micro-controller from www.microchip.com originally a 16F84 model. If you decide to process your results in real time then a PIC18F6310 for example has 3 Pulse width capture ports that can read the FGM3 data in the back-ground leaving most of the CPU for your use. If your real time results are not too demanding then most of their chip range is powerful enough to manually poll the FGM3 data without hardware pulse width capture (as with the SCL006) but at a greater rate.

While I have not checked the timing specs, a BasicStamp SX form www.parallax.com would offer a simpler approach.

What sort of sensitivity do you require as the Philips KMZ51/52 range may be useful. Anybody have a UK source for these?

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Yes, I also know that scl006 is just a microcontroller. Those 50Khz-120khz FGM-3 output make some trouble with a magnetometer design.
About KMZ: good magnetoresistive sensors with a "flipping" technology, but they have lower sensivity then FGM-3. I downloaded some information abot KMZ from: http://www.semiconductors.philips.com/pip/KMZ51.html