For my university project I want to be able to measure points on a person's leg to create a 3D image. I was thinking about having the Arduino sitting on the user's knee and a connected pointer locate the points with the position being measured by how much a couple of potentiometers have moved.
I am (almost) a complete beginner with Arduino and have only done a couple of projects previously so I am just looking for a little guidance, has anyone done anything similar or know of a simpler way to get the relative coordinates of a point, assuming the Arduino is (0,0,0).
Is the user fixed in one place, or can they walk/move around? If the hips don't move, you can use vector math to convert the joint angles to a point in space. If you want a general purpose position locator, it takes very specialized and complicated hardware.
lizdabiz:
For my university project I want to be able to measure points on a person's leg to create a 3D image.
What is the purpose of the 3D image?
This sounds like something that should be done with a camera - which is far beyond the capabilities of Arduinos. There is software available for a PC that can construct a 3D image from a series of 2D photos. Among other things people use it for creating models for 3D printing.
For my university project I want to be able to measure points on a person's leg to create a 3D image. I was thinking about having the Arduino sitting on the user's knee and a connected pointer locate the points with the position being measured by how much a couple of potentiometers have moved.
You need 3 for 3D. Can you measure what you need on a 2D plane, then 2 pots. The fewer the better.
I am (almost) a complete beginner with Arduino and have only done a couple of projects previously so I am just looking for a little guidance, has anyone done anything similar or know of a simpler way to get the relative coordinates of a point, assuming the Arduino is (0,0,0).
Thank you!
The origin should be a mechanical point like where the first pot is. It shouldn't matter much where you mount the board which is not made to be a bracket.
I would set the thing up not on the leg at all, maybe on top of a stool.
Find the coords of the knee and make the rest relative to that. Who CARES where the Arduino is?
The longer the wires between a sensor (pot) and the board, the less accurate the measure.
Just for kicks, look up 3D scanners and see how they work.
With pots the origin should be in the first pot. With a single pot you can measure either bending or rotation, decide which one you want or how to mount multiple pots to the same point.
Analog joysticks allow to measure bending in 2D, fwd/back and left/right, but they are insensitive around mid position by construction. A replacement of those special pots seems inevitable.