Hi Hannes long time no see,

If you want a schematic I'll draw one up for you but it's very simple,
basically :-

1 x LDR (Light Dependent Resistor)

1 x 100k Thermistor

1 x White LED

1 x Compass

1 x 16-bit ADC (ADS1100)

1 x 12-bit ADC

1 X Microprocessor (Picaxe 28X1 Chip)

No amplification needed, just the ADC's, I use the 16-bit ADC to read from
the temperature sensor & the 12-bit to read from the LDR.

The compass is set pointing North with the LED shining over it thus casting
a shadow from the needle onto the LDR, the shadow is set to half cover the
LDR.

I then get rid of temperature drift using math, all this is put into a black
casing shielded from external light interference.

The sensitivity is very good with minimal temperature drift.



Mark

From: magnetometer@yahoogroups.com [mailto:magnetometer@yahoogroups.com] On
Behalf Of Ing. Hannes Mayer
Sent: 18 December 2008 20:42
To: magnetometer@yahoogroups.com
Subject: Re: [magnetometer] Re: Comments needed for my 3-axis magnetometer
(using HMC1022) design



Hi Mark,

Mark wrote:
> I do not use this design anymore, i use a compass magnetometer now,
> built it a few Weeks ago, getting better results with this design.

schematic please :-)

Cari saluti,
Hannes.
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