Hi all!
I am a student and as a final project me and my partner are trying to construct a robot which orients in space using ultrasonic sensor and is able to recognize a human with infrared detector.
The question is - where to look for info on this (IR) type of detection? Maybe somebody here dealt with this kind of problem? Which parts to use, how to approach, etc. Any help is appreciated.

 

Interesting project. The human body is a diffuse source of IR, as are things like heating ducts, televisions, and ovens on the other side of the wall. Might have some fun with dogs and cats. too.

Why does the robot have to orient to anything, and what will it do once it has chosen an IR source?

 

it's a open house demo project - we'll make sure there's nobody warm around but humans.

 

What sort of algorithm are you going to use? I guess you can look at ambient temperature, and then look for some source either warmer of colder, but how do you decide it's human based on temperature?

 

I googled for more information and I did not get anything helpful.

It does seem that this is going to require some sort of differential measurement such as beenthere eluding to. It may need to be combined with some movement sensing.

Interesting project but not an enviable design challenge.

hgmjr

 

I think, what you are looking for is called Passive IR (PIR) detector.
Here's a brief article that describes how it works: http://www.totse.com/en/technology/science_technology/pirmechanics171383.html
PIR is widely used in the burglar alarm systems, and you might have some luck getting a commercial sensor and reverse-engineering it.

 

PIR triggers on movement. Empty office chairs rolling across the floor will trigger them. (Amazing how bored one can get on swing-shift.)

If people are the only things in the room warmer than the air, then any old IR detector and a comparator should work (with enough tweaking). If there are also TV sets, computers, rottweilers, and such, then something more sophisticated or sensitive will be needed.

 

Thanks everybody for the replies! Here's some info on a very similar project (form electro-tech forum guys) - http://www.seattlerobotics.org/encoder/200104/jeffd.html.
It looks more and more doable .)
I'll keep updating the tread. Thank you again!

 

A suggestion that will cost some money and time, but help you a lot:

Get a DVR card from eBay. About $20. Acquire a video camera to feed it with.

Download this software:

http://www.pysoft.com/ActiveWebCamMainpage.htm

Free download. They expect you to pay for it after a month, but you won't be using it for its intended purpose, and it will still work.

Follow these instructions:

http://www.daveandalicia.com/bt878/inst.htm

Set the sensitivity high, 95 - 97%.

Set the software to show motion.

What you will see: dozens of individual pixels light up green for no obvious reason. Moths show up as green balls. Cats, dogs, fuzzy horizontal blobs.

Humans: big fuzzy vertical blobs. The trick to recognizing humans, and only humans, would be to program the system to react only to big vertical blobs.

This assumes that you, or some other reader working on a similar project, will have a PC controlling your project.

 

Would not a cat be a big vertical blob if close enough? (We're talking robot here, POV about cat high.) And would not a human far enough away be a small vertical blob?