Measuring angle

Hello world , I am an arduino newbie . I am trying to make an ABB robotic arm (http://t3.gstatic.com/images?q=tbn:ANd9GcTOhFD6D6RgeiaTJC3rhUsjRUPaWpyWBZ9HKmIpo4UMdLmsHPmFAQ) follow my hand movement. Now the robotic arm can move along 6 axis, and the robot arms takes angle (in degrees) as the parameter for movement. I was thinking of using analog hall effect sensor. I would attach hall effect sensor to my elbows and a magnet to my arm. Now the varying readings from the hall sensor will be used to measure the angle moved by the arm along its elbows. I just want to know whether i am on the right path. If not , any suggestions from you guys regarding how to measure the angle of hand movements, will be deeply appreciated. I am on a tight deadline here guys . Please help

I just want to know whether i am on the right path

No, I'm sorry, that doesn't sound like a good idea. The Hall effect switch will be affected by ambient magnetic fields, and so repeatability will suffer.

If you're building an ABB arm, don't ABB provide the feedback mechanisms?

Also you don't get much of a range from hall sensors, in the order of a cm or so.

Thanks for the reply. See the thing is that ABB robotic arm is already built. Right now the arm moves by the command given using the keyboard or mouse. Just google "Robot Studio" and you will know. What i plan to do is that i capture the hand movements using the sensors on my hand and then use those sensor readings to make the robotic arm move by following my arm movement. That involves sending the readings to the serial port and the program, running the robotic arm, accessing the serial port to take the readings. Now i have accomplished the module where the program running the robotic arm accesses the serial port to take the reading and move accordingly (A small prototype was built using POT where the rotation on the pot was reflected on the movement of one of the axis of the robot). But what i am now looking for is a sensor which could help me detect the angle my arm makes with elbow as the axis. If according to you , hall effect cant be used then can you suggest some sensors for this application Thanks

This is a much more difficult problem than you might think. All I can suggest is some form of mechanical caliper on your arm that you can attach a pot or rotary sensor to.

Now i know why they came up with the term "Chill down the spine" , coz thats exactly what i am feeling. How about accelerometers , i think i can use those to detect the Angle of tilt. and i came across the idea of using hall sensor effect while looking at this thread http://arduino.cc/forum/index.php/topic,60387.0.html thanks