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[on:]

Over in FAQ someone wanted to have a video camera track someone but I know Arduino can't use the video to track. But how about IR?

Now I haven't worked with IR (yet) so go easy on me. This is just an idea I thought of 30 minutes ago.

Let me paint you a word picture. Imagine an average room. Now imagine a camera on a servo mount at the back of the room. At the front of the room about waist high are IR LEDs spaced about a foot apart. An IR sensor is placed at the same location as the servo/camera. (Not sure if it's stationary or attached to camera/servo unit.) Now you pulse each IR LED at different hertz. One sensor can't pick anything out of that mess so you cycle through them one at a time. Say each does a burst for 50 ms with a 25ms delay between.  The IR sensor does some calculating and looks for the missing bursts. If it finds any it spins the camera to that pre-programed "zone".

A "zone" would be a single LED or combo of 2 or more LEDs like
LED1 = zone 1
LED1 and 2 = zone 2
etc...

So as a quick example using 4 LEDs the logic would go:

Pulse LED1.
Can I see it? Yes.
Pulse LED2 .
Can I see it? No.
Pulse LED3.
Can I see it? No.
Pulse LED4.
Can I see it? Yes.

Conclusion... Object is between 2 and 3 which is zone 4. Point camera there. (3 LEDs missing would point to the center one, etc...)

And yes, as I typed this I realized you don't even need to pulse them and different hertz. Just a simple on and check will work.

If this sounds like it works I may have to try it as my first IR project.

Thanks for listening. Sorry if I'm rambling. Slow work day.

[Reply #1 on:]

I guess I WAS rambling.

[Reply #2 on:]

I disagree (about the rambling part).  Your idea seems sound to me.  It's similar to something Grumpy Mike made (on a smaller scale and for a different purpose).  I had a similar idea for detecting when and who passes through a doorway and the direction they traveled.

But, it's pointless for me to respond to the actual idea.  It's well beyond my experience so I don't have anything to offer beyond "it seems sound".

[Reply #3 on:]

It sounds like quite a good idea, I don't see why it would not work. I just recently had an idea to have cheap lasers (dollar store ones) at doors and if someone crossed the beam, I would turn one of those USB missile launchers and shoot at the door.

My only concern about this is the fact that this system might be really easy to jam. I don't have a lot of experience with IR but wouldn't a lot of sun screw up the system or if someone walks in with a night vision camera/goggles? It may not be a big deal but something to think about.

I haven't gotten my Arduino yet so I don't know the detail behind this, my firstish project is going to be a universal remote or a TVbGone clone.  

[Reply #4 on:]

My only concern about this is the fact that this system might be really easy to jam. I don't have a lot of experience with IR but wouldn't a lot of sun screw up the system or if someone walks in with a night vision camera/goggles? It may not be a big deal but something to think about.

Jamming won't occur if you shield the laser sensor properly. Also, you plan on having someone break in with nigh vision goggles? If you do then you might want to consider something more hefty than a missile launching toy  

@biocow: Unless your doing this project for the sake of doing one with an arduino, I'd suggest just setting up a wide angle camera (or more than one cheap webcam) running some simple vision processing to detect "discrepancies" - i.e. something passing in front of the wall.

[Reply #5 on:]

Yes, it's just a simple project idea to help me learn IR. Just setting up an LED and sensor would teach me but it's more fun when you have a mini project in mind.

I guess I'll pull apart my broken universal remote and do the "simple" test this weekend while I wait for IR LEDs to arrive. At least get that out of the way.

[Reply #6 on:]

People have built low def visual sensors before, like a matrix of 5x5 light sensors and a focusing lens, test the differential values between the sensors and you would have a basic camera.
Alternativly just use a nintendo gameboy camera, it has many funtions such as edge detection built in and you can talk to it with SPI.
I have also seen image scanners made from optical mouse sensor chip's, also SPI