Arduino Position Tracking Project

Hi everyone! I am currently working on a personal project where I am trying to track head motion using the arduino uno. I was looking into purchasing the MPR121 for the electrodes. I plan on creating circular copper electrodes which I will use to measure changes in capacitance. Using these changes in capacitance values I'll calculate the distance changes. Any ideas on how to approach this? I am striving for an accurate tracker.

Thanks for your time.

It's unclear to me if this touch sensor chip is suitable for accurate distance measurements.

It sounds like you are planning to build a cage of electrodes around a person's head to calculate where the head is within the cage. That sounds uncomfortable.

Perhaps there is a better way to measure the position information you want. What position information do you want?

Yes that's exactly what I am trying to do. Well I'd like to ultimately be able to know the position of the head relative to the reference starting position. Any ideas on what I should use? I am very new to this.

Thanks!

BM1594: Any ideas on what I should use? I am very new to this.

Something like a close fitting swim cap with suitable patterns and a camera (or two) and suitable image analysis software. But that can't be done on an Arduino.

...R

BM1594: Yes that's exactly what I am trying to do. Well I'd like to ultimately be able to know the position of the head relative to the reference starting position. Any ideas on what I should use? I am very new to this.

Thanks!

You can use raspberry pi and camera to track the location of the eyes to calculate horizontal and vertical location of the head, approximately.

How about simpler - accelerometer/gyro chip with RF unit (such as nrf24l01+) and processor (promini size) to send movement details to a main processor?

CrossRoads:
How about simpler - accelerometer/gyro chip with RF unit (such as nrf24l01+) and processor (promini size) to send movement details to a main processor?

This seems like a more practical way to monitor head position than using a ring of metal.

Yep, give the wearer a beanie cap, add some LEDs around that randomly flash, tell user its a mental detector indicator, have some fun with it. Or add a MAX7219, let it control 64 LEDs that you can tie to roll, pitch, yaw movement of the head for visual feedback to the experiment monitor that something is happening ...

Hi everyone. Thanks for all of your suggestions. The point is that the challenge is to implement this system in this fashion (i.e. no head cap but rather electrodes placed around the head). Any more ideas would be appreciated!

BM1594: Any more ideas would be appreciated!

So would more details. What about the head position do you want to sense? Do you care if the head rotates or tilts? What sort of precision are you looking for?

Is this to be used as an input device? It would help to know your end goal.

@DuaneDegn

Sure thing. Well I'd like to begin with a fairly simple prototype. For now I'd like to focus on head tilt as well as shifts of the head along the x,y and z axes. My idea is to place copper electrodes on each side of the head casing which is a box that the head will be inserted into. (Note: the head will be a styrofoam model covered with bare conductive paint). I am more concerned as to how I'll connect these electrodes to the arduino in order to measure capacitance changes.

My main questions are:

  1. How should I connect the copper electrodes to the arduino?
  2. What general shape and/or size should the I cut the copper electrodes?

This is supposed to be a simple prototype. Hence, I am not looking for near perfect precision but rather for a prototype that can compute the head position with some error.

Thanks for you time.

BM1594: 1. How should I connect the copper electrodes to the arduino? 2. What general shape and/or size should the I cut the copper electrodes?

I don't know what size of shape to make the electrodes but I wanted to make sure you knew about this cool copper tape.

SparkFun sells two sizes.

Two Inch Copper Tape

and

5mm Copper Tape

The tape has a layer of protective material which needs to be removed in order to solder wires to the tape.

I used this tape to shield some wires but the shielding didn't really work until is soldered a ground wire to the shield.

|216x500

I'm not sure how I removed the clear protective layer. I think I just scraped it off with an Xacto knife. I think steel wool or sandpaper would also work to remove the protective layer.

I only removed the protective layer from a small area. The area was just large enough to solder a wire to it.

This sort of copper tape might make it easier to make your electrodes.