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I am a student of Product Design & Technology at the University of Limerick in Ireland and I am developing a new product that will aid in Knee Replacement Rehabilitation. The new product will incorporate a "sensor" that will measure the angle of flexion/extension of the knee and transmit this wirelessly to the patient's physio. My knowledge of electronics is limited and as such any help in determining the components/structure of the circuit required would be greatly appreciated!

Mise le meas, Darren

A few thoughts:

Something like this:

http://www.betterbraces.com/donjoy-trom-advance-knee-brace

with a rotational sensor (a synchro or similar) on the rotary joint.

Chapter 3 of this:

http://www.analog.com/library/analogdialogue/archives/43-09/linear_circuit_design_handbook.html

describes various different sensor devices.

The rest of the book will give you a good background for the rest of the circuit design (i.e. analogue to digital conversion, power supply, general PCB design) up to the input to a processor (i.e. the output of an analogue to digital converter) and the WiFi stuff.

For the processor and WiFi, Arduino might be the thing to look at:

http://en.wikipedia.org/wiki/Arduino

Or maybe the PIC family of devices:

http://www.microchip.com/pagehandler/en-us/products/picmicrocontrollers

See also:

Practical Design Techniques for Sensor Signal Conditioning

from:

http://www.analog.com/en/technical-documentation/resources/index.html

and in particular:

http://www.analog.com/static/imported-files/seminars_webcasts/813973100sscsect6.PDF