15 ms·

Militarizing your backyard with Python, Arduino, and computer vision.

355 points by kscottz 15y ago

arandomJohn 15y ago
I attended the talk. It was pretty cool, especially the OpenCV part. Frankly I think he needs to upgrade the armaments. Hook that bad boy up to the hose with a nozzle. Frankly, if you wanted to, you could hook such a system up to an automated sprinkler control system and just turn on the water for whatever area the squirrels happen to be in at the moment. It would only have to be on for a few moments. Soon they'd think your yard is some sort of special hell, where water follows them wherever they go.
- kayz 15y ago
  I was there too :) It was such a fun talk, especially the part where in the end of the demo video, the squirrel stopped caring about the water cannon anymore, and decided to steal food while getting sprayed on. I wonder if there is a better way to deter them instead of bigger water cannons?
  - elviejo 15y ago
    Well the arms race can begin... more potent water pistol. Then nerf dart gun... then golf balls gun... then gotcha gun... (at this point gets dangerous)
- culturestate 15y ago
  You'd have to keep the sprinkler system constantly pressurized, though. I've never seen one that can do that - they all take x seconds to really get going.
swordswinger12 15y ago
15:50 for the cannon in action.
- AngrySkillzz 15y ago
  Relevant XKCD: http://xkcd.com/382/ http://xkcd.com/382/
vibrunazo 15y ago
I'm impressed that he can get low false positives with such simple methods. That's great to know. If he tried using line detection, vectorize it, then train the algorithm with the tagged shapes of squirrels. Would that be too slow to do in real time? Or could it work to reduce false positives?
- SammoJ 15y ago
  Adding complementary features such as edges (I'm guessing this is what you mean by lines) tends to improve the accuracy. It would also be possible to do this in real time. I don't have time to watch the full video so I don't know what features he is currently using, but in object detection nowadays most people are using some variant of the SIFT descriptor. These are built not upon edges but on the image gradient per-pixel. The current 'hot' feature in terms of frequency of use is probably Histograms of Oriented Gradients (HOG) which do exactly what they say on the tin: Take a region of the image and count how many times a particular gradient direction occurs and the total magnitudes. Slightly more difficult to run in real-time but libraries exist.
- kgrandis 15y ago
  I didn't show the false positive video. :P There were some additional features thrown in, but for presentational simplicity I went with some strong, easy ones to explain. I think one thing helped keep FPs low was some frame-based signal thresholding. So, I required a significant squirrel signal (over multiple frames) before it went hot. That prevented any small FP blip to trigger the gun.
SudarshanP 15y ago
One of the spectators in that video talks about http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html which was discussed on HN before and a nice demo of what computer vision can do...
jamesbowman 15y ago
As the person who wrote the OpenCV Python bindings, this makes me inordinately happy.
- bicknergseng 15y ago
  I imagine the team behind Kinect feels the same way when lightsaber-anything gets made.
- Riesling 15y ago
  As a person who used those bindings in a couple of projects (this includes tutoring the computer vision course at uni) I will use this opportunity to say thanks.
- fgimenez 15y ago
  I don't say this enough to people like you, so THANK YOU SO MUCH!
- doctoboggan 15y ago
  Awesome, I have been using the your work a lot recently. I do have one question though, is SIFT available in the python bindings? I have not been able to find it. Thanks for contributing your time, it has made my life much easier.
  - apu 15y ago
    For SIFT computation, I recommend VLFeat[1], which there are some python bindings for[2] (although I haven't tried them myself). [1] http://www.vlfeat.org/ http://www.vlfeat.org/ [2] http://www.janeriksolem.net/2011/06/another-python-interface-for-sift.html http://www.janeriksolem.net/2011/06/another-python-interface...
    - kscottz 15y ago
      Jan Erik is an outstanding guy. He has helped me through a couple of rough spots. The OpenCV python bindings for SIFT don't seem to work (or exist). The ones for ORB work really well. Here is an example: https://github.com/ingenuitas/SimpleCV/blob/master/SimpleCV/ImageClass.py#L3994 https://github.com/ingenuitas/SimpleCV/blob/master/SimpleCV/...
rauljara 15y ago
I think a fair number of homeowners would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.
- nl 15y ago
  I think a fair number of nation-states would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.
  - Estragon 15y ago
    I think a number of terrorists are going to be willing to figure out how to hook such a system up to a gun on a $300 RC quadrocopter. I hope it's a small number. It's going to be interesting.
    - thesis 15y ago
      Are you serious? Do you honestly think a $300 RC quadrocopter can handle the kick of a gun?
      - aero142 15y ago
        I'll bet it can handle a 22 short.
        pilgrim689 15y ago
        A terrorist with a bomb is a threat. Terrorists with rickety flying .22s... That would just be fun to watch!
        Confusion 15y ago
        Stampedes due to a gun being fired in the middle of a crowd are not fun to watch. Terrorists aren't out to do such things though; surprisingly, they have other goals than causing random terror. Psychopaths on the other hand...
trebor 15y ago
What about airsoft? You could mount a cheap, automatic, battery-powered unit and seriously sting those squirrels! I thought of using a similar system to protect the chickens I've got from the feral/neighborhood cats (I do have a fence... but that doesn't feel "complete").
- woodall 15y ago
  We have chickens too, around 25 free range + a pony + a few ducks, and had issues with dogs and wild coyotes. I think harming the animal is a bit inhumane but I totally understand where you are coming from. Remember you are a guest in their space. Here are some suggestions that have worked for our farm: 1. Pee around the coop. Enough said. 2. Get a puppy and train him. We have an aussie that does a great job, but there are other breeds that make even better farm dogs. 3. Train the chickens to go back into the barn when the sun goes down. This isn't very hard and most of the time they will do it themselves. 4. Motion sensor and/or electric fence on a timer. 5. Be aware; this is by far the hardest thing. Our first year we lost 10 chickens. If that's not motivation enough to do something, I don't know what is but I would never hurt another animal for doing what they do naturally.
  - trebor 15y ago
    Our chickens aren't exactly free-range, but they have a large fenced-in area. The fence is electric, and the chickens do go in at night. But when a cat walks by and scares them, they have a tendency to get outside the fence and not know how. And outside the fence... some of the cats would be interested in getting them. And since a big siamese-like cat comes around that will hunt ground hogs, a chicken isn't such an intimidating target. While I understand that cats are born predators, I can't afford to lose chickens. I wouldn't kill them because they do keep pests down and may belong to someone, but I do want to scare them away from the coop.
    - woodall 15y ago
      Oh yeah, I understand that. We all face different challenges when raising animals. I was just spitballing at 'cha.
trotsky 15y ago
Awesome talk, but I can't resist: Leave it to a software engineer to find a $250 solution to a $10 problem :) (http://www.wbcboulder.com/pole_mounted_baffles_sub.html http://www.wbcboulder.com/pole_mounted_baffles_sub.html)
- TamDenholm 15y ago
  Well sure, but its not really about that, its about the process, figuring out how to do this stuff and then doing it is extremely enjoyable and really cool, as is doing a talk for others who think the same thing.
- MaxGabriel 15y ago
  He has trees from which the squirrels can leap to the feeder
- simcop2387 15y ago
  I can tell you right now that those don't work at all. We've got a few on our feeders with NOTHING else around them and the squirrels still get on them. They only work if you have a single feeder/pole within about 10 feet of each other. Those little fsckers pull some ninja-esque moves jumping from metal pole to metal pole to get around them. It's entertaining to watch but it can get expensive since when they get up there they eat their fill which can sometimes be 1/6th to 1/5th of the feeder at a time.
  - HeyLaughingBoy 15y ago
    they eat their fill That's when you apply the $5 solution: a slingshot.
- platz 15y ago
  Innovation in technology comes from using technology in ways it wasn't intended, not necessarily what is the most efficient.
prawn 15y ago
Reminded me a bit of this old project from someone trying to stop non-cats or their cat carrying a dead animal from entering a cat door: http://www.quantumpicture.com/Flo_Control/Flo_Control_1/flo_control_1.htm http://www.quantumpicture.com/Flo_Control/Flo_Control_1/flo_...
javajosh 15y ago
Seems like you'd be better off cutting off the approaches to the feeder. But the project is super cool. For more power, I'd use a power washer. :)
- polyfractal 15y ago
  Squirrels are notoriously ingenious at raiding feeders. They are really good at defeating feeders that are specifically designed to be "anti-squirrel" too.
ams6110 15y ago
A real python would probably take care of the squirrels even better.
8ig8 15y ago
The presenter's personal site: http://kurtgrandis.com/blog/ http://kurtgrandis.com/blog/
liquidcool 15y ago
I wonder if something like the Blender Defender (http://www.plasma2002.com/blenderdefender http://www.plasma2002.com/blenderdefender) would be more effective than the water. A strobe light and/or a rattle to frighten it off. Ultrasonic would be good as well if there was decent evidence it worked.
Ecio78 15y ago
My bro has a problem with a mole digging all the backyard, any idea for that problem? maybe a flying drone that drops bombs on its head ? :)
mogui 15y ago
neat and awesome talk

355 points by kscottz 15y ago

I attended the talk. It was pretty cool, especially the OpenCV part. Frankly I think he needs to upgrade the armaments. Hook that bad boy up to the hose with a nozzle. Frankly, if you wanted to, you could hook such a system up to an automated sprinkler control system and just turn on the water for whatever area the squirrels happen to be in at the moment. It would only have to be on for a few moments. Soon they'd think your yard is some sort of special hell, where water follows them wherever they go.

kayz 15y ago
I was there too :) It was such a fun talk, especially the part where in the end of the demo video, the squirrel stopped caring about the water cannon anymore, and decided to steal food while getting sprayed on. I wonder if there is a better way to deter them instead of bigger water cannons?
- elviejo 15y ago
  Well the arms race can begin... more potent water pistol. Then nerf dart gun... then golf balls gun... then gotcha gun... (at this point gets dangerous)
culturestate 15y ago
You'd have to keep the sprinkler system constantly pressurized, though. I've never seen one that can do that - they all take x seconds to really get going.

swordswinger12 15y ago

15:50 for the cannon in action.

AngrySkillzz 15y ago
Relevant XKCD: http://xkcd.com/382/ http://xkcd.com/382/

vibrunazo 15y ago

I'm impressed that he can get low false positives with such simple methods. That's great to know. If he tried using line detection, vectorize it, then train the algorithm with the tagged shapes of squirrels. Would that be too slow to do in real time? Or could it work to reduce false positives?

SammoJ 15y ago
Adding complementary features such as edges (I'm guessing this is what you mean by lines) tends to improve the accuracy. It would also be possible to do this in real time. I don't have time to watch the full video so I don't know what features he is currently using, but in object detection nowadays most people are using some variant of the SIFT descriptor. These are built not upon edges but on the image gradient per-pixel. The current 'hot' feature in terms of frequency of use is probably Histograms of Oriented Gradients (HOG) which do exactly what they say on the tin: Take a region of the image and count how many times a particular gradient direction occurs and the total magnitudes. Slightly more difficult to run in real-time but libraries exist.
kgrandis 15y ago
I didn't show the false positive video. :P There were some additional features thrown in, but for presentational simplicity I went with some strong, easy ones to explain. I think one thing helped keep FPs low was some frame-based signal thresholding. So, I required a significant squirrel signal (over multiple frames) before it went hot. That prevented any small FP blip to trigger the gun.

SudarshanP 15y ago

One of the spectators in that video talks about http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html which was discussed on HN before and a nice demo of what computer vision can do...

jamesbowman 15y ago

As the person who wrote the OpenCV Python bindings, this makes me inordinately happy.

bicknergseng 15y ago
I imagine the team behind Kinect feels the same way when lightsaber-anything gets made.
Riesling 15y ago
As a person who used those bindings in a couple of projects (this includes tutoring the computer vision course at uni) I will use this opportunity to say thanks.
fgimenez 15y ago
I don't say this enough to people like you, so THANK YOU SO MUCH!
doctoboggan 15y ago
Awesome, I have been using the your work a lot recently. I do have one question though, is SIFT available in the python bindings? I have not been able to find it. Thanks for contributing your time, it has made my life much easier.
- apu 15y ago
  For SIFT computation, I recommend VLFeat[1], which there are some python bindings for[2] (although I haven't tried them myself). [1] http://www.vlfeat.org/ http://www.vlfeat.org/ [2] http://www.janeriksolem.net/2011/06/another-python-interface-for-sift.html http://www.janeriksolem.net/2011/06/another-python-interface...
  - kscottz 15y ago
    Jan Erik is an outstanding guy. He has helped me through a couple of rough spots. The OpenCV python bindings for SIFT don't seem to work (or exist). The ones for ORB work really well. Here is an example: https://github.com/ingenuitas/SimpleCV/blob/master/SimpleCV/ImageClass.py#L3994 https://github.com/ingenuitas/SimpleCV/blob/master/SimpleCV/...

rauljara 15y ago

I think a fair number of homeowners would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.

nl 15y ago
I think a fair number of nation-states would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.
- Estragon 15y ago
  I think a number of terrorists are going to be willing to figure out how to hook such a system up to a gun on a $300 RC quadrocopter. I hope it's a small number. It's going to be interesting.
  - thesis 15y ago
    Are you serious? Do you honestly think a $300 RC quadrocopter can handle the kick of a gun?
    - aero142 15y ago
      I'll bet it can handle a 22 short.
      - pilgrim689 15y ago
        A terrorist with a bomb is a threat. Terrorists with rickety flying .22s... That would just be fun to watch!
        Confusion 15y ago
        Stampedes due to a gun being fired in the middle of a crowd are not fun to watch. Terrorists aren't out to do such things though; surprisingly, they have other goals than causing random terror. Psychopaths on the other hand...

trebor 15y ago

What about airsoft? You could mount a cheap, automatic, battery-powered unit and seriously sting those squirrels! I thought of using a similar system to protect the chickens I've got from the feral/neighborhood cats (I do have a fence... but that doesn't feel "complete").

woodall 15y ago
We have chickens too, around 25 free range + a pony + a few ducks, and had issues with dogs and wild coyotes. I think harming the animal is a bit inhumane but I totally understand where you are coming from. Remember you are a guest in their space. Here are some suggestions that have worked for our farm: 1. Pee around the coop. Enough said. 2. Get a puppy and train him. We have an aussie that does a great job, but there are other breeds that make even better farm dogs. 3. Train the chickens to go back into the barn when the sun goes down. This isn't very hard and most of the time they will do it themselves. 4. Motion sensor and/or electric fence on a timer. 5. Be aware; this is by far the hardest thing. Our first year we lost 10 chickens. If that's not motivation enough to do something, I don't know what is but I would never hurt another animal for doing what they do naturally.
- trebor 15y ago
  Our chickens aren't exactly free-range, but they have a large fenced-in area. The fence is electric, and the chickens do go in at night. But when a cat walks by and scares them, they have a tendency to get outside the fence and not know how. And outside the fence... some of the cats would be interested in getting them. And since a big siamese-like cat comes around that will hunt ground hogs, a chicken isn't such an intimidating target. While I understand that cats are born predators, I can't afford to lose chickens. I wouldn't kill them because they do keep pests down and may belong to someone, but I do want to scare them away from the coop.
  - woodall 15y ago
    Oh yeah, I understand that. We all face different challenges when raising animals. I was just spitballing at 'cha.

trotsky 15y ago

Awesome talk, but I can't resist: Leave it to a software engineer to find a $250 solution to a $10 problem :) (http://www.wbcboulder.com/pole_mounted_baffles_sub.html http://www.wbcboulder.com/pole_mounted_baffles_sub.html)

TamDenholm 15y ago
Well sure, but its not really about that, its about the process, figuring out how to do this stuff and then doing it is extremely enjoyable and really cool, as is doing a talk for others who think the same thing.
MaxGabriel 15y ago
He has trees from which the squirrels can leap to the feeder
simcop2387 15y ago
I can tell you right now that those don't work at all. We've got a few on our feeders with NOTHING else around them and the squirrels still get on them. They only work if you have a single feeder/pole within about 10 feet of each other. Those little fsckers pull some ninja-esque moves jumping from metal pole to metal pole to get around them. It's entertaining to watch but it can get expensive since when they get up there they eat their fill which can sometimes be 1/6th to 1/5th of the feeder at a time.
- HeyLaughingBoy 15y ago
  they eat their fill That's when you apply the $5 solution: a slingshot.
platz 15y ago
Innovation in technology comes from using technology in ways it wasn't intended, not necessarily what is the most efficient.

prawn 15y ago

Reminded me a bit of this old project from someone trying to stop non-cats or their cat carrying a dead animal from entering a cat door: http://www.quantumpicture.com/Flo_Control/Flo_Control_1/flo_control_1.htm http://www.quantumpicture.com/Flo_Control/Flo_Control_1/flo_...

javajosh 15y ago

Seems like you'd be better off cutting off the approaches to the feeder. But the project is super cool. For more power, I'd use a power washer. :)

polyfractal 15y ago
Squirrels are notoriously ingenious at raiding feeders. They are really good at defeating feeders that are specifically designed to be "anti-squirrel" too.

ams6110 15y ago

A real python would probably take care of the squirrels even better.

8ig8 15y ago

The presenter's personal site: http://kurtgrandis.com/blog/ http://kurtgrandis.com/blog/

liquidcool 15y ago

I wonder if something like the Blender Defender (http://www.plasma2002.com/blenderdefender http://www.plasma2002.com/blenderdefender) would be more effective than the water. A strobe light and/or a rattle to frighten it off. Ultrasonic would be good as well if there was decent evidence it worked.

Ecio78 15y ago

My bro has a problem with a mole digging all the backyard, any idea for that problem? maybe a flying drone that drops bombs on its head ? :)

mogui 15y ago

neat and awesome talk