Can you get motion detection sensors to selectively trigger...

Thread Starter

tmh556

Joined May 21, 2022
3
Hi,

I apologize I'm new to this so might not be explaining this well but was wondering if it is possible to get motion detection sensors to trigger selectively at a certain mph or size of the object that is triggering it? Any info would be greatly appreciated. Thanks, Tom
 

ericgibbs

Joined Jan 29, 2010
15,748
hi tmh,
Welcome to AAC.
Which type of sensors are you considering, is it for animal or material type objects etc.?
What detection range.?
E
 

Thread Starter

tmh556

Joined May 21, 2022
3
Again, new to this all so not sure the sensor type. It would be trying to detect a large metallic projectile (1 meter in length), probably 100 feet range or more with speeds of the projectile at roughly 300 mph.
 

Alec_t

Joined Sep 17, 2013
12,907
It would be trying to detect a large metallic projectile (1 meter in length), probably 100 feet range or more with speeds of the projectile at roughly 300 mph.
I would suggest a radar set-up, or camera with image-recognition, as possible options.
What's your budget for this?
 

Ian0

Joined Aug 7, 2020
5,581
Motion detectors are either passive infra red (PIR) or microwave.
PIR types detect a warm object moving in and out of the zones created by the lens. The bigger and warmer the object the larger the signal.
Microwave types return a signal which is the transmitted signal (usually 10.7GHz) doppler shifted due to the motion of the object. The return signal is mixed with the transmitted signal to give sum and difference frequencies, the difference frequency is proportional to the speed of movement of the object - which is how radar speed guns work.
The amplitude of the return signal is proportional to the fourth power of the distance and the size and reflectivity of the object.
 

BobTPH

Joined Jun 5, 2013
5,294
One meter long projectiles moving 300 mph sounds a bit dangerous to me. What, other than military, could the application of this be?

Bob
 
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