Dakota Alert Sensor Cover Attack!

I’ve been using Dakota Alert MURS Alert Transmitter for many years. I’m on my second one, and once again I have an animal (bird probably) attacking the white paper cover in the sensor port.


  1. Is it made of special paper?
  2. Can I color it darker to make it less tempting?
  3. Is there a better way to protect the PIR detector?

Many years ago DA sent me some of the paper so I could tape it over the front of the port, but I’m hoping there’s a better fix. Wondering if I’m the only one dealing with this issue.

Digikey, as well as other manufacturers, have a selection of PIR freznel lenses available. You will want to measure the focal length (distance from sensor to broken lense). When you find one with the same dimensions and focal length, buy a whole bag (they’re cheap).

Or is there a freznel lense behind that and this broken thing is just a window? Any IR transparent plastic would work for that.

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Here’s an idea, Put some wire screen (you will have to experiment with the size) over the lens port once you’ve fixed it (see above).

That should keep the birdies from pecking your plastic.

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Thanks for advice. I thought of doing that, but suspected the metal screen would interfere with the reception. Have you actually done this? I may have to do some experimenting.

Those ******* birds are still at it. Every time I replace the paper cover they attack. I’d like to find a plastic ring that fits, so I can put the paper deeper in the unit like the original. Then, if my experiments pan out, I could put a metal screen at the end.

Paint the front of it to look like a cat. Wide mesh wire screen should not interfere with the IR detection.

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That’s funny. I don’t think they’d be afraid of a tiny cat. I filled it with mothballs, and that didn’t slow them down at all. As soon as I get time I’m going to try test the metal screen idea. I’ll post my result here.

As someone who has a lot of birds in his backyard year round, I’m going to take a wild guess that they mistake the transmitter as a birdhouse or possible nesting place and the sensor port as the opening to it. If you look at it from a bird’s eye view, it certainly does look like one.

The solution is a simple one, although it will require a little work. Encase the entire unit in a clear plexiglas housing. This will provide the sensor with an unobstructed view and prevent the birds from getting to the unit. This will also offer additional weatherproofing.

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Is plexiglas transparent to the NIR (8-14um)? It might need to be thin to work. Some of the opaque plexi is better at transmitting NIR.

I have one of these same transmitters from dakota murs, although I don’t use it anymore as it sits out in the tree with dead batteries, but mine came with a wood birdhouse to hide it. That wood birdhouse had a single vertical wire and a single horizontal wire blocking the PIR window hole and I have not once had an issue. Either the wires work or your birds are more determined than mine. Just go with wire to start with, your unit is already waterproof and the manufacturer does that already.

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I’ve seen those birdhouses, but I didn’t know about the wire. Thanks for that real world info.

Now I know that at least one wire of some kind of metal will work. It gives me hope. My next step will be to find or manufacture a properly sized ring so I can put my paper cover deeper inside the tube.

I even tried putting a handful of mothballs inside the unit. Didn’t bother them at all.

I can run down the road and take a picture of mine (if its still there). I believe the wires are thin, but I don’t see thick ones being an issue. I can even throw some batteries in it and staple more wires to the front and see what happens… Im kinda bored out here in the woods anyhow.