Track position of an object with respect to another one

Hi everyone,

I am very new to Arduino and electronics in general, I would probably say almost a total ignorant.

For my project, I would need to be able to track the position of an object with respect to another one. For example, you can think of two sensors (which ones?) attached to the two wrists (right and left) and in some way I got the position of the right wrist (in X,Y,Z) compared to the left wrist, so that I know the position (at least on one axis, say the Z) of the right wrist with respect to the left one. I would be happy already if I could see when the two wrists are at the same height actually, without had to know the distance between them, the rotation etc..

  1. Is it feasible with some cheap sensor?

  2. I heard about gyroscopes and accelerometer to achieve this, is this right?

  3. If that's right, would you know the right name of the components I should buy?

  4. do you know of some tutorial for the coding part? Otherwise, I'll spend some time on it

Thank you for your attention

About the only inexpensive sensor suitable for non-contact distance sensing on an Arduino are the ultrasonic range sensors (like the $2 HC-SR04).

With some circuit snipping (make one 'send only' and the other 'receive only') two can be used to measure the distance between two moving points. They need a speed-of-light connection (wire or radio) so they can be triggered 'at the same time'. That would give you distance but not relative coordinates in some fixed coordinate space.