I am planning on using some online schematics to make my multimeter also convertible to a gaussmeter. One DIY page said I could find a Hall Effect Sensor in CD ROM and DVD players. Where might this be located in the players?

 

We have a few old DVD players so I suppose I'll extract the motor, laser, variable resistor dials and some other things too.

Dismantling those may be too damaging. Easier source are computer fans. If you do not know how to dismantle one (remove label and tiny circlip) It is on the circuit board.

 

Shown here----> http://www.pcbheaven.com/wikipages/images/thumbs/howbrushlessmotorswork_1269516340.jpg

HRS, I don't know if you are aware, but there are hall sensors and hall switches. I understand you need a sensor (analog output), while switches (digital output) seem more common today.

 

But I don't know if there is any hall analog sensor in a CD/DVD player, sorry.

Hall effect sensors are dirt-cheap, just buy:

http://www.conrad-electronic.co.uk/ce/en/overview/0231410/Magnetic-Field-Detectors-Hall-Sensors

I've seen some meant for use with a multimeter: properly calibrated and with the convenient connectors.