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[on:]

Hey everyone,
I hope someone could push me in the right direction.. Basically I'm trying to do this..

http://www.sparkfun.com/products/8630

It doesn't make sense to me how an IR sensor and a camera could "sense" a person and that person's movement..

I have the thought that the Arduino needs to understand what a blank sidewalk "looks" like and then compare that image to one when someone walks by..

But then when a person is within the field of vision, how can I track a person's movement forward and back. That is very confusing..

ANY help is MUCH appreciated..

Thanks
Todd

[Reply #1 on:]

The PIR sensor just gives an output when someone or some living thing wanders through it's field of vision. It is not a camera it is just a single sensor giving a single reading of the amount of long wavelength IR radiation there is. If there is more than there was when it was first switched on you get an output, that's all it is.

But then when a person is within the field of vision, how can I track a person's movement forward and back

You can't.

[Reply #2 on:]

That's what I thought. So I wonder how they did it??

Ok, I did see this, which in theory is very similar, but instead of controlling a motor, I'd like to control video playback..

http://www.niklasroy.com/project/88/my-little-piece-of-privacy/

The code is there, but I get lost where he created the display and it analyzes the video..

Any thoughts??

Todd

[Reply #3 on:]

So I wonder how they did it??

Do what?

but I get lost where he created the display and it analyzes the video..

He is not using an arduino.

[Reply #4 on:]

I'm not sure exactly what you are trying to achieve, but I do like the idea of a tracking curtain.

If you are controlling video playback, then why does the position of the subject matter?

If you just want to trigger playback when someone moves in front of you, then the PIR sensor would do fine. If you want to know which direction they came from, then 2 pir sensors separated could tell you this by their order of triggering.

They will not work through a window, they sense IR (heat).

[Reply #5 on:]

It looks like this person used processing or some other image processing language with a movement detector module. Basically you take an image of the background pavement (sidewalk as you would say), and use this as a reference image. Then take an image and subtract each pixel from the corresponding pixel in the reference image to produce a difference image. Then scan along the X axis from the left until you reach the first non zero pixel. Do the same from the right and the target is between these two values. Do this for all lines and take the maximum value in from both ends and the center to draw the center line.

Then you know where your target is, send that information over the serial port to an arduino controlling a motor with a pulse counter on it and move the motor to the position corresponding to the target.

The arduino only plays a small role in this project.