Ok, advanced project. Detecting the presence/absence of my trash can. "We" have a problem remembering to bring down the trash can (and on alternate weeks, the trash and recycling can)
The can is parked on the side of the house, generally in the same spot in the grass. The Trash can has a large blue lid. I think it'd be sufficient to detect a "large blue spot" visually. The recycle can never goes up on it's own. So if the "blue" lid is missing, so is the "green" lid.
I'm thinking this is going to have to be solved using a camera, and perhaps a bit of "AI" on a PI or something. Kinda like -- "if 25% of the camera frame is blue, then the can is present".
No clue on how to put those parts together -- but that's what I've thought of.
Color rendition suffers tremendously in low-light conditions, so if you base detection on "blue", you're apt to get lots of false negatives during rainstorms, nighttime, etc.
May get farther using an ultrasonic or RFID solution, although even that is a bit overkill for trashcans. Though I doubt GPS would fare any better (unless your driveway is pretty long!) paired with Location sensing.
I like the RFID option, also thought of using an IR proximiy sensor. I just did some pantry lights that came with one to tell if the door is open and it works perfectly. I would have never have thought to use something like that if it didn't come with the kit.
I founds some beam style ones like on a garage door, and a single one like my pantry light uses.
Might be able to wire them up to some sort of zigbee module and use it like a contact sensor?
How about a simple tether that either attaches to the trashcan or goes around all of them... at the end of the tether is a magnet that sits against an outdoor contact sensor like the Ring. If the contact sensor is closed the tether is in place. If the tether is not in place the magnet would pull away from the contact sensor, therefore the trash cans have been removed. It would require the tether be put back into place when the trash cans are returned but you're already out there moving the cans around. And this has the advantage of no AI, no cameras, just a cheapo contact sensor.
Could you mount a contact sensor on the side of your house and a magnetic strip on the bins? Then as long as the bins are pushed up against the house it would register that they are there.
I really like the magnetic strip or magnet attached to the trash can and contact sensor on the house. Simple and highly reliable, as long as the person(s) returning the trash can know where to put it.
I made an ultrasonic parking assist/stop light with an Arduino for my wife's car in the garage. The ultrasonic sensor would have no problems detecting the hard plastic can within a certain range. Perfect placement wouldn't be necessary.
Ultra sonic sensor. I have one (I made) in the garage to sense if my vehicle is in the garage. When I come home at night, open the garage door a tilt sensor sets off an ultrasonic measurement to turn all the outside and some inside lights if it is dark out.
Bond a metal plate to the bottom of the can. Bury a coil under the spot where it resides. Use a metal detector circuit to sense the presence of the can.
Both the above require some more advanced electronics. But not undoable by the noob with a mission. The first one I made using boards from eBay. Only soldering was to connect the different boards together. i.e. you don' have to actually build circuits.
UPDATE:
How about a simple light sensor ( I have an Xiaomi ). mounted at the beginning of a tube (PVC??) with the tube pointing at (nearly touching) the garbage can. It would sense any light difference (with and without Can) but only during the day.
Maybe not ideal but real simple to implement.
Cool, but ours would never make it back on the pallets. Our garbage is picked up by trucks with mechanical "arms". When putting the cans back down they are always offset from the original location.
Maybe -- I'd have to build a "platform" or something for the trash cans to sit on -- right now, it's just grass.
Looked briefly -- I think the distance is too great and/or the non-WAF of putting the cans "just so".
Ok, that has boggled my mind as well. ALL of the cans in the neighborhood are that way. It's the cans supplied by the waste management company. I've just adapted, although my OCD wants to "fix" it. Since it's done this way for a reason, alas that reason escapes me, I leave it be.
So far, ultrasonic, seems to be the best idea. I remember old polaroid cameras that had the ultrasonic sensor. And I also think some cars have an ultrasonic sensor for detecting things close to the bumper. I think we're in the distance needed for that to work.
