> [Spikes] work IFF you buy the right ones AND put them absolutely everywhere AND are careful to actually mount them correctly AND you don’t plan to use the area covered yourself at all AND you don’t even want to look at its disgraced looks. So it is completely pointless for a balcony.

They can also be horrifically cruel. I've seen a pigeon die after getting impaled on those kinds of spikes and it was a traumatic experience for me, let alone the poor bird. I really appreciate your attempts to solve this problem without resorting to inflicting pain, or worse.

Did something similar. My wife was upset about the flying rats defecating on her flower pots on the terrace. Those birds are stationary (generally) and slow so I managed to iterate a solution that (a) used a 3w green laser mounted on a webcam with servos and (b) later used a static laser with a mirror that was mounted on a set of servos. I used a stationary 4k webcam. I mapped the whole terrace so I didn't need to use stereoscopic vision. When a bird was detected (i sampled images at 1fps and built a custom model for pigeons, it was generally ok at avoiding other birds, but not perfect), i'd triagulate its position and light it up for 100ms. I used a similar contraption as the OP to cut the power. The pigeons would react by flying away, even when hit from behind or underneath. I used a series of experiments before settling on 3w. 1w was not enough.

It solved the problem for good. Its not a perfect solution, obviously: i had to implement a master override which stopped it when terrace doors were open, also it only fired at horizon or below since I didnt want to accidentally light up a plane (there is an airport 5km from where I live). We dont have kids, and rarelh entertain guests, so I didnt need to implement additional safety Measures. Lastly, it was running on a pretty beefy pc and was consuming around 60w constantly.

We fixed the problem for good by moving out. If i had to do it again, I'd try with water pistols, way safer than laser.

“After a quick burst of manic energy during exam phase…”

It’s amazing what humans are capable of achieving while avoiding doing something else.

Hi HN! I commented about this project of mine a month ago [0] and decided to write a more in depth blog post about it.

Feel free to ask any questions :)

[0] https://news.ycombinator.com/item?id=31024099

I built something similar using the same internals of a battery operated water gun. I 3d printed a 360 turret enclosure, stuck it on a stepper motor. However mine was manually controlled via my phone. I used it to break up cat fights in the middle of the night

If you want the low-tech solution, here is a recipe that definitely resolved it for me:

- One big spoon of cinnamon

- One big spoon of chilli peppers

- Half a bottle of cheap, cleaning vinegar

Spray it in all the places that the pigeons want to land. I am doing that once a week and it is enough to keep them away. If you clean your whole balcony with it, you might be able to go through most of the spring - when I think they really get annoying because they are looking for a place to make a nest.

Consider using background subtraction for this: https://docs.opencv.org/4.x/d1/dc5/tutorial_background_subtr...

Will make things a little more robust (and overengineered!).

I've been daydreaming about something like this for my squirrel problem. The damn things nearly leave me without nectarines unless I install a cumbersome, unsightly net over the tree.

Tom Lehrer solved this one years ago:

https://m.youtube.com/watch?v=yhuMLpdnOjY

This is funny. I've tried to make pigeons come into my terrace to feed them and allow them to nest with no success at all. Yet other people struggle to keep them out of their balconies :D

Not as much fun to build and deploy, but equally effective is pigeon-repellent adhesive. It prevents the birds from landing on treated surfaces and is not too unsightly.

https://www.nixalite.com/product/4-the-birds-gel-repellent

Deer devouring flowers. Off the shelf solution. Motion activated sprayers attached to hose. Worked great, but.

1. Looked like crap. Scifi minitowers in my yard. Hoses stretched here and there. 2. Randomly activating at night. Not loud but quite audible, and disturbing. 3. Occasionally zapped people, skunks, cats.

So I sold them to a friend (they aren't cheap)

Any interest in over engineering it a bit more? We did something similar to spook rabbits[1] in a garden using a computer vision model to detect them (vs your masked motion sensor). Looks like lots of users have shared pigeon detection datasets[2] that could make a good starting point.

[1] https://blog.roboflow.com/rabbit-deterrence-system/

[2] https://universe.roboflow.com/search?q=Pigeon&t=subject

I hope that at least one person pauses to consider the pigeons' close relation to us on the family tree of life, the fact that they have feelings and personalities and can experience joy and pain.

The most effective solution I found for pigeons (although I haven't built this so can't compare...) is feeding them at regular times. It doesn't even have to be a lot. They're smart enough to know I come out around 0830 to give them some seed, and then they fly away for the rest of the day because no more food is coming. Sometimes when new babies appear, it takes a couple of weeks for them to copy the pattern though.

I’d love to have an overenginnered (or not!) solution for the starlings in my neighborhood. Their horrible screechy calls drive me mad. But the fact that it’s sound and not poop that’s the motivation probably makes it a more difficult problem to solve, since it relies on both sound (to find where the demonspawn is) and vision (to not hit some random screechy kid).

Starlings can sing melodic songs too, and I don’t mind those, but what I hear most often are their screeches. They are literally doing it right now outside my window. I wonder if it’s a territorial ”song” that I’m hearing more often than Europeans do since they’re an invasive species in the US, or if this particular call is a learned behavior from the population in my city.

The only theoretical solution that I’ve come up with so far is something that listens for the offending sound pattern, verifies that it’s also a “small dark bird” via camera, and then chases it off a water gun or laser or pocket nuke or stern words or whatever. All of that tech is beyond me, but I’ve definitely fantasized about it ever since they showed up here a few years back.

Cool project! A simple solution that worked for my balcony and window sills was to leave a few cm of reflective tape [1] in some strategic places.

[1]: https://www.amazon.de/-/en/gp/product/B073W7VR6L/

Had to solve this problem at two separate places and boy was it a journey. The pigeons ignored everything, even the spikes; we later found one sitting in nest built directly atop of them, looking all cozy (place was unoccupied at that time). What actually worked was two things: a net and a cat. The net broke once after some strong winds, so needed maintenance, but otherwise works okay, albeit the ugliness factor. The cat solution was a bit unintentional thanks to ... lets say involuntary adoption, but he takes care of problem with flying stars. The pigeons even seem to have started avoiding the place. This is on the fifth floor as well and he thankfully did not manage to yeet over the railing yet, though I wouldn't be surprised given how enthusiastic he is. We did weave a mesh through the railing in a measly attempt to reduce this risk.

IIRC, homing pigeons use infrasound (sound waves below 20 Hz) to navigate, so it may be worth trying them instead of ultrasound in the hope common pigeons too would be sensitive to them. That would require some power and a bigger transducer (namely a subwoofer); still a lot better than having to deal with their excrement.

Anyone notice how few birds there are nowadays? Used to see them all the time. I live in a bird sanctuary. I see the same 25 birds every day. Used to be thousands. Maybe insects have collapsed. Maybe it's just us. I wish we could stop killing things.

I hate spikes and nets. Have seen some pigeons die slowly and rot in them. It was horrible and would have kicked someone's ass if I knew who installed them.

Here's a solution implemented by a friend a couple of years ago. It detects pigeons and shoos them away by waving a stick with ribbons: https://towardsdatascience.com/how-to-use-deep-learning-to-s...

I've been looking at some automated way to scare coyotes out of my yard almost every night at 3am. It drives the dog nuts.

"Plastic crows Pigeons get used to them"

When i lived in a small appartment with a baclony i was advised to get a (small) statue of an owl to get rid of pigeons. I bought one at our local el-cheapo market and it seemed to do the job. Didn't monitor it though, becuase i didn't care that much.

At a very high end hotel with a very large veranda, they ran what looked like clear fishing line horizontally.

A cheap solenoid will work with garden watering systems and connections. I made an irrigation system that I added to Home Assistant and it’s great.

https://www.bunnings.co.nz/pope-25mm-solenoid-valve-with-flo...

You can get attachments that allow all sorts of jets, drips and spray patterns.

It would probably plug in nicely in place of the water gun. However drilling through the wall and messing with the plumbing isn’t for everyone.

Also works great for keeping kids off your lawn

Yes, I left seeds, bread and other stuff pigeons and other small birds may eat, and also provided some kind of shelter, but the only visits we have here -no matter if I provide food or not- are seagulls, which I'm not interested in.