Hi eveyone , i have a question for all you experts i can't find an answer to.
What motion detector can i use as a switch to operate a device iv'e made in a shop window that detects passers by on the other side of the glass . Iv'e made it with a PIR and all was working well in the workshop and didn't realise that PIR's don't work through glass. Any idea what other sensors i could use?
Help please.
Is there something like a PIR except with visible light? Even if there isn't, you could make a photodetector circuit that reacts to changes in the photo-detector's output.
No ;the glass is not coated ,we have PIR sensors in our house and have discovered that by placeing a sheet of glass over these they don't detect anything even at very cose range . I assume they detect heat and the glass acts as a barrier.
A light detection circuit sounds a good idea ,are there any circuit digrammes available on this site?
It'd be a whole lot simpler to simply wire the sensor up outside. All it'd take is a single drill hole and re-wiring the sensor, but it near the top of the window and no one's even gonna notice it's there. Like mneary said if you have eaves it's even more perfect you can recess it up, completely out of site.
What about IR LED's as illumination? If they're bright enough it'll reflect off the people outside and set the PIR off? Worth testing at least.
Sorry i'm missleading you maybe , I cant hard fix anything to the shop ,this device will be inside the window as part of a display to sell items and may only be there for a few weeks until it's moved to another store so hard fixing anything is a bit too much . I thought about ultra sonics but think some form of light sensor is the only way forward , just don't no what to use .
What about IR LED's? The increased IR illumination may make the PIR work through the glass, you'll just need to put the LED's right up next to the glass to avoid reflections.
Ir = Infrared. It's a shot in the dark though not idea if it'd work or not but it would make sense to me. I'm just not sure what part of the IR spectrum PIR sensors are sensitive to. If it's far IR it's usless as IR leds are near IR.
Ir = Infrared. It's a shot in the dark though not idea if it'd work or not but it would make sense to me. I'm just not sure what part of the IR spectrum PIR sensors are sensitive to. If it's far IR it's usless as IR leds are near IR.
Hi eveyone , i have a question for all you experts i can't find an answer to.
What motion detector can i use as a switch to operate a device iv'e made in a shop window that detects passers by on the other side of the glass . Iv'e made it with a PIR and all was working well in the workshop and didn't realise that PIR's don't work through glass. Any idea what other sensors i could use?
Help please.
And here's a little info on them
**broken link removed**
I'm sure if you look around you can find one cheaper. You do not need one with "dual technology". That type uses both IR and mmicrowave and will only go off of both are tripped simultaneously. You could of course modify one to bypass the IR factor.
Thanks for the replies , microwave would seem a good bet and looking at whats available there is a vast choice .They emit radiation and are safe more that 50mm distance , doe's this mean they will do harm if closer?, i don't wan't to get cooked.
Depends on the output power, I wouldn't put it close to living tissue though, even if you don't get 'cooked' the small localized heating is not good for the cells.
A little camera will do it. There's a small camera Kit sold for robotics that has a PIC or AVR included, and will provide output signal to track a red object, or tell if something has changed in the camera image. Like a "scene" sensor that tells you if there is movement in the scene.
I think I saw someone using the kit over at Seattle Robotics if you wanted to do a search.
Thanks for the replies , microwave would seem a good bet and looking at whats available there is a vast choice .They emit radiation and are safe more that 50mm distance , doe's this mean they will do harm if closer?, i don't wan't to get cooked.