Mosquito-repellent LEDs, anyone?

[enricosavazzi]

https://www.ebay.co.uk/itm/273555940254

 

This seems to be a LED COB emitting an unusually broad spectrum, if one takes at face value the emission spectrum published in the eBay ad. Something is obviously wrong with the diagram of the spectrum however, since the horizontal axis labels are, from left to right: 200 400 300 500. Also, the spectral color bar is wrong because it shows violet next to red. Yet another curious inconsistency is that it says "mosquito repellent" in parts of the ad, but "attract mosquitoes" in others, and even "exterminator" elsewhere.

 

Besides being the first claim I noticed of a mosquito-repellent LED, the above "errors" in the ad destroy any credibility to the claims of the seller. Aside from that, I doubt I could comfortably sleep with a 50 W LED COB shining on my face. Let alone something that supposedly kills mosquitoes by exposure to light.

 

Also note that April 1 was not so long ago. However, the eBay ad seems legitimate.

[dabateman]

Well at 4cm x 6cm thats one large led that apparently doesn't have any light pollution. 

[Andy Perrin]

Heh. The LED mosquito devices I’ve seen mostly claim to attract the bugs, and then they get trapped and zapped. Basically a mechanical version of a pitcher plant. 

[colinbm]

These Cree LEDs are blue LEDs with a phosphor coating that emits a longer wavelength, in this case a yellow.
Your regular white light Cree LEDs are a blue LED with a yellow phosphor that emits a white light.
In Australia we have yellow fluorescent tubes that are used to NOT attract insects in out-door entertainment areas.

[ulf]

I found the same array on Aliexpress:

https://www.aliexpress.com/item/32883918757.html?spm=a2g0o.order_list.0.0.21ef1802t4kZkd

Here they claim to attract the insects.

 

 

[enricosavazzi]

2 hours ago, ulf said:

I found the same array on Aliexpress:

https://www.aliexpress.com/item/32883918757.html?spm=a2g0o.order_list.0.0.21ef1802t4kZkd

Here they claim to attract the insects.

I can understand that these LEDs may be used as part of a "mosquito zapper" device, where the light attracts insects and a high-voltage electrified net kills and fries them. I think I can read this "between the lines" of the eBay ad, although the information in the ad is presented using atrocious language, syntax and logic (or lack thereof). As a former technical writer, I would suggest to this company to hire the services of a knowledgeable communicator.

 

In practice, this LED COB is an updated equivalent of fluorescent tubes used for the same purpose in legacy "mosquito zappers". Depending on its actual emission spectrum, it might or might not be something worth for us experimenting with. The emission spectrum diagram has too many peaks to be produced by multiple LED types alone. Some mix of phosphors must also be involved. If it includes 275 nm LEDS (which are becoming reasonably cheap lately) and their radiation escapes from the phosphor and coatings, this device is far from safe to use in proximity of unprotected eyes and skin.

[aphalo]

The array in the Aliexpress/eBay pages linked above is also described further down the same page as mosquito repelent and in other places as zapping the insects, and they look yellow-green in the illustrations. The spectrum is non-sense as it has a peak at 100 (nm?) and emission at what would be 30 (nm?) and the colors in the bar below the x-axis are in the wrong order in addition to not matching the wavelengths. Difficult yo know what they are actually selling...The other thing to be aware is these LED arrays are connected directly to mains, so are dangerous to put next to a baby or anyone for that matter, irrespedtive of whether they emit UV or not!

 

The LED bulbs earlier sold as mosquito lamps in AliExpress/eBay seem like white LED bulbs filtered to block the blue part of the spectrum (one can see a very small second peak in the blue).  The idea is that yellow light does not attract mosquitos as much as white light because it lacks the shorter wavelengths. I bought one mosquito bulb a couple of years ago out of curiosity and measured the spectrum.

 

 

 

[Fandyus]

I mean, just from experience, I can say that UV sources are extremely attractive to insects. Last summer when I had UV sources on at night and my window open, I wold start getting random insects in my room within 5 minutes. Not very pleasant. A lot of then were larger types too, not just small flies.