PIR motion tracking?

[HarveyH42]

Only have a small understand of PIR modules, so need some general information. I know they are three leads, +5volts, ground, and output. Output is either high or low when it detects.

Haven't been able to determine if two modules mounted close together, but angled so their field of detection only overlaps a little, will interact or confuse each other (false detection). The idea would be to pan the sensors until both detect the intruder (feline), and activate the deterant. When nothing is detected the sensors will rotate back to a home position.

Also don't know the effects of moving the sensors on detection. Will it need to be stationary to get a accurate detection, or will it work the same while in motion. I've only seen where they are mounted in a fixed position (alarms and security lights).

How much influence does sunlight have on these sensors. Only outdoor uses I've seen were motion lights, so suspect that daytime isn't a good time, which is okay.

 

[Hero999]

I don't see how the sensors can interfere with each other as they dont give of any electrical noise or heat.

PIRs ony respond to rapid changes in heat to lighing shouldn't make any difference providing it changes slowly enough although I don't know whether sunlight will overload the sensor or not.

I wouldn't think moving the sensors whilse they're operating is a good idea since they'll probably trigger sporadically. Your best bet is to use an array with each sensor overlapping the other's field of view and ORing the output.

 

[HarveyH42]

Hmm... going need to do some part shopping, and look at some datasheets. I invisioned that by moving the sensors, the cat would be basically centered when both sensors are activated. The cat is kind of slow and cautious, a male, so guessing he's looking to get with one of the neighbor's cats.
For an array, think I would need to put the sensors in tubes to narrow the field they can see. Six sensors would give me five target areas. Need some sort of encoder to mark these positions.

Really need to see how long the sensor need to detect, and how much motion. Datasheets...

 

[HarveyH42]

Did some more searching and reading. Didn't find any actual part numbers to look datasheets for, but did go to the big guys store yet either. Not much on just the PIR module part, mostly the whole unit stuff. Decided to search for PIR projects, maybe I'm not the only one...

**broken link removed**

Similar is some ways, but what caught my attention was the PIR units. I have some of those. Electronic Goldmine had them on sale at least a year ago. The have a built in 433 transmitter, but no luck getting it to work with any reciever I had. Have to dig the out tomorrow and wire up something quick and simple. Think I can use two diodes as an OR gate to active one relay to power a motor, another relay for forward/reverse. Think the built in delays on the PIR units will be a small problem, but should see if this might work....