Hi fellows!
is it posible to reduce minimum viewing distance at 5V PIR sensor? Right now minimum is about 3 meters and I need only 0,3 meter. Maby I can change some resistors or potentiometer?
I see two potentiometers. If one is sensitivity, use that.
How do you expect anyone to help you if you do not provide for your PIR the manufacturer, the model, and/or a link.
How about some tape over the sensor?
To reduce the min distance requires a different focal length. Thus need to change the Fresnel lens. Try finding a smaller one that will fit.
gerrikoio:
To reduce the min distance requires a different focal length. Thus need to change the Fresnel lens. Try finding a smaller one that will fit.
I'm using sensor without plastic lens. If I change potentiometer to other one maybe this could help?
Since its not a lens but a set of prisms(*), there is no range as such, but the size of object needs to scale with distance, so
if its good at spotting person-sized features at 3m, it will spot mouse-sized features at 0.3m most readily.
The way these sensors work is by sensing changes in heat radiation - the prism system means that a moving
heat source will appear to turn on and off from the sensor's point of view as one prism directs radiation on to
the sensor and another directs it away - in other words change of angle becomes change in apparent luminousity.
If you fill its field of view then movement won't cause change at the sensor. If you are tiny compared with
the angle between prisms the variation may be too small.
(*) Take off the plastic dome and you'll see the inside is broken up into prismatic segments of various angles.
vaj4088:
I see two potentiometers. If one is sensitivity, use that.
But... the sensitivity pot is not for sensitivity/distance.
It's a time delay before the sensor reacts.
Sort of a false positive eliminator.
Try this
Cut a piece of white paper into the size of a coin.
Remove the dome (just pull it off), and place it there before putting the dome back on.
Leo..