Hackaday Prize Entry : DEER — An Electronic Repellent

Ultrasonic repellent devices used to keep away insects, rodents, birds, and even large animals have been around for quite a while, but their effectiveness depends on who you ask.  Some critters just don’t seem affected, while some others definitely will avoid being around such a device. Deploying a few of these devices to scare off animals seems to be working quite well for [Ondřej Petrlík]. Around where he lives, the fields of tall grass need to be mowed down during the spring. Unfortunately, the tall grass is ideal for young, newborn animals to stay hidden and safe. The mowing machines would often cripple and hurt such animals, and [Ondřej] desperately wanted to solve the problem and prevent these mishaps.

He built an electronic repeller to keep away wild animals and their young from his farm/ranch/range back in the Czech Republic. He used an Arduino Mini to drive a large piezo transducer to scare away the wild animals from the vicinity of the device. He likely used a high enough frequency beyond human range, but we’ll know more when he publishes his code and details. There are also a few large 10mm LED’s – either to visually locate the device or help drive the animals away in conjunction with the ultrasound, with an LDR that activates the LEDs at night. Using the Arduino helps to turn on the transducer at random intervals, and hopefully, he is using a range of different frequencies so the animals don’t become immune to the device.

His first prototype was cobbled together using vanilla, off the shelf parts. An Arduino, a step up converter, an LDR, a couple of LEDs, a reed switch for powering it on via a magnet, and a large ultrasonic transducer, all powered by three alkaline AA batteries. He stuffed it all inside a weatherproof molded enclosure, holding it all together with a lot of hot glue. This didn’t make it very rugged for the long-term, outdoor field use. While the prototype worked well, he needed several of the devices to be placed all around his farm. To make assembly easy and make it more reliable, he designed a custom PCB to fit in the weather proof enclosure. This allowed him to easily mount all the required parts for a more reliable result. His project is still a work in progress, so if you have worked with these types of ultrasonic repellent devices to keep away animals, and have any insights that may help him, do chime in with your comments. [Ondřej] seems pretty satisfied with the results so far.

37 thoughts on “Hackaday Prize Entry : DEER — An Electronic Repellent

    1. Maybe the method should involve making a ‘robot’ (RC vehicle) that races around the area for a while instead of trying to make a huge system covering it all at once? Because yeah to be efficient it would need a lot of power, but something skittng around making noise will make anything/one nervous and want to leave

      1. I had this idea too. But the goal of the project was to design equipment that is simple to manufacture and is mainly cheap. Someone may lose, break, or steal the device. So the cost of the new ones should not be drastic.

        They are also installed on site only a few days before chopping.

        1. awesome project,
          when trying to photograph deer i have noticed that they might be able to marginally see the infrared lights used in cheap night vision gear, my grandfather have had similar issues with trying to track the deer on his property, he was using a cheapish wildlife cam and couldn’t understand how few shots of deer he got, compared to the dozens of sightings a day, waking up to a herd in the garden is commonplace there, yet with 3 cameras on the common deer paths he might only get a single deer shot a night.

    1. I think I’d prefer to implement a motion detection and tracking system using OpenCV that lobs a one litre glob of water at the animal from a laminar flow nozzle.

        1. Good point, it lights up for a moment (~10s). The light is not so strong to keep staring. And I hear they’re afraid of cars because from some cars they are shooted. So they do not like the lights.
          It’s not legal hunting, but it’s happening.

  1. Arrrgghh… deer. No predators other than cars in our neighborhood. ‘Rats with antlers’ as David Qammen put it.

    The best tasting deer are locally grown, hosta fed.

    1. Well, that’s what happens when we drive out the natural predators…not that you’d want them close to our homes anyway, since they’re wolves and bears :P

  2. If the noise isn’t enough, take any rap song, and just change the octave way up to something we can’t hear. Play it on repeat over and over – that’s enough to chase away even a turtle.

  3. I don’t know about Czech deer but North American Whitetail Have a hearing range UP TO 30 kHz but tuned to the 2-8 kHz range, roughly equal to our own hearing. So while they can hear ultrasonics they can’t hear them WELL so the range isn’t going to be great, that combined with possible effects on non-target species just sort of rules that out for me.
    Something more alarming and easier to hear like human speech could be good though, some sort of randomised human voice gibberish like what those talking neural networks spit out… Or a sprinkler system like everyone else is suggesting.

      1. Well now you got me thinking about those ‘radar’ sensors from a few days ago. Would be great to have something in my garden to scare off the raccons and cats.

    1. Hello, Ondřej here. It does not use ultrasonic range, the range of sound of repellers is between 200Hz and 15kHz, so it is also heard for human beings. Currently, I use three pre-arranged different sounds that are randomly selected and the number of their repetitions is also random in range 1-5.

      The code is almost finished, I plan to publish it soon.

  4. Met an old guy way up north that sold hand-made deer whistles that actually worked. Sold two models, 3 or 4 wooden whistles mounted together with each whistle at a slightly different frequency.

    One sound at one frequency bounces differently than another does. Car moving, deer hears it coming from over there, then it changes to over here , then suddenly comes from right behind it! Deer bolts right in front of you as apparent source of sound was jumping around!

    Several frequencies together of course bounce around a lot more and from multiple different directions, but clearly the loudest single source is the mixed frequencies coming from the front bumper of your car. Deer consistently move away from it. You can notice yourself standing on the roadside to test.

    Wood though, it rotted away after years, but can make them by buying a few different models, or changing the resonant chamber volume with some epoxy.

    Well tested. There’s a highway up north at 4am the deer are as thick as the mosquitos… used to take it at 25 mph for 35 miles. With good tri or quad whistle it’s fine at 55 again. Suggest mandatory for motorcycles at night.

    Tip. Take it off during the day… else everyone it town stares RIGHT at you as you cruise through town.

  5. “hopefully, he is using a range of different frequencies so the animals don’t become immune to the device.”

    You have to use rolling frequencies, or the deer will adapt quickly and assimilate you.

  6. Firecrackers. When I lived in Honolulu some years back, you could buy a roll of 100,000 at Costco for under 20 bucks. That would scare off a lot of critters if deployed appropriately.

  7. Hmm, as a resident of Pennsylvania, this appeals to me.

    #1 US state (by wide margin) in absolute numbers of car/deer collisions, and #2 in relative probability of a deer/car collision. I had two road-killed deer on my lawn in a single​ year. Tuens out one of the services our tax s is a special “dead deer” removal service.



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