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Ask HN: Recommendations for physical intrusion detection in pastures
15 points by aspyct 31 days ago | hide | past | favorite | 23 comments
Hello HN, hope you're doing well!

There's a wave of horse mutilations in France, Germany and Belgium. I am directly concerned by this, as such incident happened this week close to where my horse lives.

We stood watch last night, but it's immediately become clear that we can't do that every night. Also, we can't afford a night guard, it's too expensive and this wave could last for years (it's been over a year in France).

I'd like to setup some kind of intrusion detection and alerting in the pastures. It is a wide open area, and animals regularly move around in there. Horses, obviously, but also rabbits, foxes, birds etc.

So far we are considering cameras, but that is going to be an expensive solution, and we need to be alerted only when humans are around.

I'm at a loss so far. Tired, also, haven't slept tonight.

We need this deployed as soon as possible, every day matters. I'm willing to take any quick and dirty solution. We have manpower to install equipment, and some money (but not that much) to get equipment. I can also administer infrastructure and develop custom software, so feel free to suggest anything.

Cheers folks!

Do you have a link to a news coverage of this?

The story and mutilations look very similar to the epidemic of chupacabras attacks that we had in Argentina in 2002. It was covered for a month by all the major newspaper and TV stations. [spoiler alert: it was just the misclassifications of the result of mice and foxes and other animals eating the corpse]





EDIT: Perhaps you can put a bluetooth detectors in the necks of the horses that sends a signal to your home. I guess the attackers will forget to turn off their cell phones and you can try to detect them. (Anyway, my main hypothesis is that is a misclassification.)

..... but a few quiet voices have raised the possibility that no one is responsible for the shocking injuries. On 3 September, Le Monde pointed out that they could be a natural phenomenon – horses that have hurt themselves or died naturally and been set upon by scavengers such as foxes and crows. Previous scares, from the US to Germany, have eventually been explained this way. In the UK, in the decade from 1983, a rash of horse mutilations was widely blamed on a “horse ripper”, but despite prolonged investigations no conviction was ever made. Experts concluded that most of the injuries were sustained through accident or post mortem. A fox’s teeth are razor sharp, apparently; they can inflict damage that closely resembles a knife wound.... From https://www.theguardian.com/commentisfree/2020/sep/23/horse-...

Definitely not chupacabras, unless they drive cars :)

I intentionally didn't post link to news coverage, because that's graphic and, quite frankly, I don't want this post to become a badge of honor or suggestion for some of those people who could be around.

If they found car tracks, my guess is that they misinterpreted them as simultaneous to the attack. Perhaps they were older tracks. Perhaps some newer tracks after the animals died and the owner or some relative took a look.

Try to read a few reports of somewhat similar case, like the one I linked. We agree that in neither case the explanation is the chupacabras. But it is interesting to see how a bad explanation can get a lot of media coverage and the evidence misinterpreted.

Also, try to get some sleep. If your explanation is correct, you would think a better and build a better system with enough sleep.

(And no bobby traps, you may kill a relative or a innocent bystander.)

No, you don't get it. We've seen the people trying to do it. We've chased them. They're real, they use ropes and knives. Those are not random accidents.

- With camera if you have some high vantage point which sees the whole field, it may help reduce the cost by needing only a single camera, if you can scan and zoom in the area. Maybe infrared/thermal camera is also helpful if the attacks happen at night. The human infrared signature is easily identifiable at night : a human sized blob of the right temperature.

- If you don't have a high vantage point, you can try using a balloon anchored via a rope (hydrogen (cheap but illegal) or helium).

- (If you like the technological challenge) Quadcopter drone with ardupilot at random intervals : goes up, snap a picture, goes down and land and wait on the ground to preserve battery. You can also have it land on a base station to recharge automatically. Probably hard to do when weather is not nice.

- Maybe there are some unused at night road to access the area that are likely to be used by the aggressors. Either positioning a camera there, or car counting device / induction loop may be a good bet.

If there are multiple access point, you probably can incentivize the intruders to use the easy way-in but discreetly controlled by for example putting barb-wires, electric fence everywhere, warning signs, fake camera boxes, (airsoft motion activated landmines ?), cheap radar motion detector coupled to sound alarm, ...

Usually if there are significant visible signs that the property is well monitored, intruders will pick another easier farm.

Ahah, extra points for the helium filled balloon. I'm installing cameras tomorrow, but I really got to try the zeppelin method at some point :)

Thanks for the suggestions!

1. Game cameras. They are purpose built for this kind of need. Your strategy should be to identify/establish clear routes in and out of your local area, and then set up an intel network in cooperation with neighbors. If you can network basic cameras, you can feed the input to a face/person recognition software. Say once every 30 seconds its sends the frame to an AWS instance or similar, and if it sees a person it rings the alarm/email alert.

Siesmographs and other such sensors can detect and track vehicles causing vibrations, some can be laid in roadway.

There are also some sensors that will detect only humans, via the ammonia our sweat contains, but I dont know if those ever made it to the public market, they were tippy top secret for the longest time.

2. Dogs. There is a landowner near me who is responsible for $5M+ of equipment and facilities. In addition to cameras and such, he has trained dogs that roam around at night. If you are already a livestock handler, adding "kennelmaster" to your job is a great way to solve your problem.

PS. There was a wave of this in my home state in the 80s. It was a combination of cults practicing, and uncommon diseases killing off livestock, which wild animals then tore apart to eat only what wasnt rotten.

Ah, sending the frames to a server for analysis, good idea! Thanks :)

My first thought is leveraging an electric fence like a trip line. The line has to be cut or tripped for something or someone to get in. I’d be very surprised if you can’t find a remote voltage monitor that can tell you real time if the fence lacked adequate charge. Heck, you could run a wire from the fence to an accessible location to manually check the wire with a fence tester and it its light goes red, you know the fence is down.

We have an electric fence, but you can cross it without cutting or touching it :)

Have you tried putting a cheap phone heart monitor / sound monitor / sleep monitor app on the horse directly ?

I.e. you let the horses tell you when they feel stressed.

Depending on the network quality you can stream everything and process in the cloud.

Building on that, some battery powered GPS units these days are getting relatively cheap and can be used to stream location data. My guess would that in the event of a disturbance, the horses would be much more active (moving around) more than one might expect? Integrated with the above; it strikes me that you need some 'disturbance-phenotype' to detect for. IE, you can get the data-loggers and instrumentation onto the beast, but then you need a way of defining 'disturbance'.

Maybe once you've got that definition you can set up some spotlights to come on automatically once a certain level of 'disturbance' is met?

That's worth investigating. Horses do sometimes run around, because they're scared of just for fun, but that would be a good study anyway :)

I installed Nest Outdoor cams at my in laws last week. They can do person detection, thus you'd only be notified if a human being moves around the stable.


Ah that'd be neat, but we need to cover a lot of fields, and that's going to be real expensive real quick :(

Perhaps a tall pole with some realistic looking dummy cameras to start. Along with very prominent signs that activity in the area is being recorded.

Another idea, corral your horses at night. Get them in the habit of coming back to a protected area for evening feeding, lock them in and let them out in the morning.

We thought about restraining the horses to a smaller parcel, but ultimately we decided against that, so they have more free space to run away. They won't be more than 100m away from us at anytime though

Quick and dirty - tripwires either on the gates or ground (more prone to false positives) and hook them up to either electronic alarms, flood lights, or starter pistol blanks (if legal).

We thought about tripwires, yes. But what are they exactly? Thin electric cables that break? Since we already have fencing, that could be a good solution

If it's on a gate it could use two electric wires that touch when closed and open the circuit when the gate is open. Of course that would have to be hooked up to a sensor.

I'm not sure what the laws are there, but I'm guessing this is next option is illegal there as it is here. You could hook the metal gates to an electric line. The screams would alert you.

The other way to do it is to use tripwire line or braided fishing line hooked up to an electronic alarm (pulls a pin or tab to alarm) or ammo blank alarm (pulls a trigger to fire the blank). Put it a few inches off the ground or attach it to a gate.

You can also use lasers as a tripwire device. They make them for driveways so it will make a doorbell-type noise to alert you that people are coming. This could be a great option if you have to come down a driveway or path to get to the horses, but you may get false alerts with deer. You can also use this between your outer and inner fence (if you have that style).

That's good info, thanks!

Maybe a baby monitor? Very cheap solution though I can't speak to their range.

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