EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: shakalnokturn on October 26, 2020, 04:03:40 pm
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Not much of a project yet, just looking for reference material and ideas in case it does become one.
While working on electronics late at night when the house is quiet I regularly hear a wood eating insect in one of the ceiling joists.
Considering the wood used and the crunch heard I expect it to be a single longhorn beetle larva.
I'd prefer avoiding a thorough pesticide treatment on a large zone for what sounds like a single insect.
I'm imagining it must be possible to locate the insect inside the joist to reduce the volume that needs curing with insecticide.
X-ray could be one solution although I don't have the equipment and getting access to corners may not be convenient. I also imagined fitting a magnetron with partial enclosure to the joist to fry the enemy in place but I'm not comfortable with such levels of stray RF...
A slower but more technical idea would be to triangulate the insect in the wood with a set of acoustic sensors.
A quick look on Google shows that the acoustic approach has been used to detect and identify (as in "crunch acoustic signature") wood eaters using DSP to filter out the background noise, I haven't seen any examples of locating a larva in a volume of wood though.
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Years ago I repaired an insect detector for a pest control company. There wasn't much to it, just a good sensitive microphone, an amplifier and a speaker but we tested it and it worked well for detecting wood chewing insects. The sound that they make is very distinctive and there's usually nothing else in a house making noise that can't be easily shut off. I would suggest trying something simple before diving into the complexities of DSP and the like.
BTW It's very difficult to kill insects once they bore into wood but I used to put old cigarette butts into insect holes. The nicotine in the butts killed them dead and no bug ever used that hole again!
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https://www.youtube.com/watch?v=fH_x3kpG8Z4 (https://www.youtube.com/watch?v=fH_x3kpG8Z4)
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A simple DIY method would be to use 2 contact microphones.
"Contact microphones usually are piezo electric discs with a weight attached to them, and they are designed to pick up sound waves in solid materials. You can find them very cheaply on Aliexpress / Ebay / China / Etc, or buy higher quality ones in your local muzic store. They are commonly used to stick on insturments, to pick out the sound of that single instrument in an orchestra.
If you use 2 of them with a stereo input and some sound analyzing program, you can get a rough estimation of the location of the critter by the time delay. If you measure no phase difference, the critter is in the middle. If it's closer to one of the microphones, you get a phase difference.
Also, once you've managed to record the sound signature of the creature, you can probably find what animal it is from some online database. And this may help in narrowing down in what it's habits are, where to find it, extermination methods, etc.
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are you sure that that particular beetle did not just find a crunchy piece of wood and the other beetles are not eating non crunchy wood?
I highly recommend you do not make any assumptions on bug count when they are destroying property and structural elements. If something is eating your house its not the time for scientific research and complex analysis.
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While working on electronics late at night when the house is quiet I regularly hear a wood eating insect in one of the ceiling joists.
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Just crank up the tunes!
https://www.youtube.com/watch?v=iEsLzoY6zL8 (https://www.youtube.com/watch?v=iEsLzoY6zL8)
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I think the Magnetron solution is also used in commercial treatment of infested wood.
Magnettron, some tinfoil shielding to protect the room, remotely switched powerplug...
However I would certainly ask a professional bug hunter before risking any damage to the house...
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Nature already found solutions: ichneumon wasps ... https://en.wikipedia.org/wiki/Ichneumonidae (https://en.wikipedia.org/wiki/Ichneumonidae)
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That must be the most adorable wasp I've ever seen.
And it's female too. ::)
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Thermal imaging cameras are used to detect termites and locate the nest. I guess they generate heat chewing all that wood.
https://www.flir.com/discover/professional-tools/detecting-pests-with-thermal-imaging/ (https://www.flir.com/discover/professional-tools/detecting-pests-with-thermal-imaging/)
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Terahertz imaging might work even better. Whatever became of that gadget that was being sold?
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(https://upload.wikimedia.org/wikipedia/en/9/98/Aardvarkant.jpg)
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I'd prefer avoiding a thorough pesticide treatment on a large zone for what sounds like a single insect.
I'm imagining it must be possible to locate the insect inside the joist to reduce the volume that needs curing with insecticide.
I also imagined fitting a magnetron with partial enclosure to the joist to fry the enemy in place but I'm not comfortable with such levels of stray RF...
You can use substances that are completely safe for people and nature, such as copper sulfate or table salt, to destroy the enemy.
You can't get it with a magnetron - there is a lot of moisture in the wood that will shield the radiation.
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BTW It's very difficult to kill insects once they bore into wood but I used to put old cigarette butts into insect holes. The nicotine in the butts killed them dead and no bug ever used that hole again!
You came across non-smoking insects, they went to those who lead a healthy lifestyle. :-DD
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You can use substances that are completely safe for people and nature, such as copper sulfate or table salt, to destroy the enemy.
You can't get it with a magnetron - there is a lot of moisture in the wood that will shield the radiation.
One of the safer insecticides are borates. A mixture of borax and boric acid is used to dip wood products to render them inedible to insects and fungi. With a diethylene glycol carrier, it can even penetrate finished wood pieces. Boric acid is about as toxic to people as table salt. There are also ways to inject insecticide foams into small holes drilled in posts.