Bug zapper "tennis racket" - Page 1
Forum section: electronics / projects

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 22, 2020, 02:40:39 pm
content: Just a brief note to say that I've just ripped a couple of the current crop of these apart (rectangular cross-section handle) in order to put in decent batteries. An 18650 will just about fit, and the board has an 8050SS on it which looks like it's rated for 5V.They're not quite up to the standard of the last one I did which had a couple of D cells strapped to it. Flies which got that up 'em either took up smoking, or- and this is slightly spooky- headed rapidly for the nearest open window or crack between door and frame.MarkMLl

author: Johnboy
author_rank: Regular Contributor
timestamp: July 22, 2020, 04:27:24 pm
content: That's very interesting about the flies seeming to sense the souped-up racket. If it is really the modification that causes them to flee, I wonder at what threshold their "spider sense" kicks in.

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 22, 2020, 04:40:04 pm
content: It needs to connect, but not enough to cause significant damage. At that point they develop an urgent interest in following an airflow to safety, I find the level of awareness this implies disturbing.I've just belted one with a well-charged racket, there was a loud crack. The cap does claim 2000V rating...MarkMLl

author: james_s
author_rank: Super Contributor
timestamp: July 22, 2020, 06:13:24 pm
content: Those things are fun. I was on a group camping trip about 10 years ago where there were so many flies it was unpleasant to sit still. Somebody found that a nearby store carried those zapper racquets and bought several. Handed them out to the kids that were there and they had a great time running around zapping flies, pretty soon they were virtually gone and we could all enjoy ourselves.

author: tooki
author_rank: Super Contributor
timestamp: July 22, 2020, 10:12:14 pm
content: I wish they’d had those when I was a kid, I woulda had a blast with it!I still do to an extent now. :p

author: VK3DRB
author_rank: Super Contributor
timestamp: July 22, 2020, 10:33:05 pm
content: Quote from: james_s on July 22, 2020, 06:13:24 pmExecuting flies and mozzies en-masse has unexpected ramifications because they are all part of the food chain. It seems anything humans interfere with in nature, there are side effects...https://en.wikipedia.org/wiki/Four_Pests_CampaignMind you, there is nothing worse than flies and mozzies at a barbie.I have one of these racquets here which I use for an el-cheapo ESD tester. It can give a nasty zap if not careful.

author: tooki
author_rank: Super Contributor
timestamp: July 22, 2020, 10:41:23 pm
content: It’s one thing to kill the skeeters in a small area, and quite another to attempt to kill all of them in a huge country.

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 22, 2020, 11:00:55 pm
content: I love those rackets.I Love zapping mosquitos! Frying ROACHES! Ahh, the smell of burning bug.Problem is most of them are junk.I have only found one so far that had good balance and was light but not fragile.Most of the ones I find now are too heavy and stiff.Those big heavy ones with D batteries are just too stiff.

author: Larryc001
author_rank: Regular Contributor
timestamp: July 23, 2020, 03:25:21 am
content: Ha! This takes me back to mishaps in my past. Like the time I tried to measure the voltage with my DMM. Needless to say I had to buy a new one after that. Or the time I rested my hand on a fully charged one. Ouch!

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 23, 2020, 04:03:39 am
content: Quote from: Larryc001 on July 23, 2020, 03:25:21 amThat obviously wasn't a very robust meter - Joe Smith tests with larger capacitors and higher voltages.

author: james_s
author_rank: Super Contributor
timestamp: July 23, 2020, 04:28:18 am
content: Quote from: VK3DRB on July 22, 2020, 10:33:05 pmI don't go outside just to kill insects, but I'm entitled to use the outdoors now and then too and there is no shortage of bugs. I seriously doubt that zapping a few hundred of them that are ruining an outdoor gathering is going to do irreparable harm to the ecosystem. They're welcome to go harass some other creatures instead of us.

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 23, 2020, 05:13:00 am
content: Quote from: james_s on July 23, 2020, 04:28:18 amI bet you didn't even ask them.

author: floobydust
author_rank: Super Contributor
timestamp: July 23, 2020, 05:30:02 am
content: I'd have no problems with mosquitos going extinct. No love for bugs here and a research experiment confirmed mosquitos are not a vector for corona viruses.The bug zapper HV power supply has a small 3V version and a beefier 3.7V Li version, around 1,400-2,000VDC.I see them commonly taken out and used for electric mousetraps. There's lots of youtube videos on that but they mask some parts and I suspect they beef up the output capacitor from stock 0.022uF? 2kV to much larger. Some videos show massive electrolytic can-type caps (but obviously hollowed out) and a 12V battery which just makes no sense.edit: reposted schematic as it became cross-linked to another picture

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 23, 2020, 06:22:21 am
content: Quote from: VK3DRB on July 22, 2020, 10:33:05 pmAs are humans, and we have a right to defend ourselves.MarkMLl

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 23, 2020, 06:29:36 am
content: Quote from: floobydust on July 23, 2020, 05:30:02 amAt least some of those videos are using cattle prods as a voltage source, and the degree of coyness makes me suspect that things aren't quite as they appear. After all, the idea is not to tell people how to eliminate vermin (I'm pretty damn sure that in one case the rats get recycled for multiple performances) but to make money from advertising.MarkMLl

author: Johnboy
author_rank: Regular Contributor
timestamp: July 23, 2020, 07:00:07 pm
content: There is enough room on a piece of excrement to support as many flies as will fit. I wonder how many flies actually die as a result of starvation because the ecosystem cannot support them.An unpleasant thought, perhaps, but there do not seem to be a shortage of maggot candidates for flyhood.As a child on family vacations in the bush, my cousins and I applied flyswatters with gusto so that our family could picnick in peace without flies setting up shop on every plate and brazenly planting their flag in the potato salad. It was futile. No matter how many we killed, there were always more to take their place at the table.So I am wondering about the use of electricity as a deterrent to flies, as opposed to merely using the rackets to execute them. There seems to be a tiny possibility that some flies could be less sensitive to it, and that once you cull those individuals from the herd, this problem becomes more manageable. Whereas swinging at them with conventional perforated plastic flyswatters just weeds out the slow and/or the aged.How could one use a fly as a NCV test subject? There used to be electric "Bug zappers" in people's backyards in the 1980's in the US... These often sported purple "UV" bulbs to attract insects. I don't recall them killing houseflies by the thousands, so could it be possible that flies (and some other insects) know to give them a wide berth?

author: james_s
author_rank: Super Contributor
timestamp: July 23, 2020, 07:44:49 pm
content: I still have an old bug zapper, however I don't bring it out often. They don't work for flies for the simple reason that flies are not attracted to light. They do a nice job on moths, gnats and other fairly harmless but irritating bugs though, and they do kill some mosquitoes too.

author: floobydust
author_rank: Super Contributor
timestamp: July 23, 2020, 08:10:34 pm
content: Does UV LED light attract mosquitoes and flies? They sell a night stand and most racquets have UV LEDs in them. I have not tried it.UV fluorescent tubes are still used in the food industry for this.

author: Johnboy
author_rank: Regular Contributor
timestamp: July 23, 2020, 08:42:07 pm
content: UV frequency light doesn't seem to attract houseflies (unlike mosquitoes?), but light does, generally. That seems to be how a flybottle prevents them from escaping. I suppose one could try smearing a light film of potato salad on the interior portion of the ring of the racket. IME they seem to enjoy that stuff. There are other substances that might draw them more readily, but I'm leaving that one to the imagination.Didn't mean to hijack the thread. I was looking around and saw that many people have posted a schematic and DIY tutorial for one of these devices. I could do without the homily that precedes the instructions in this one, but at least I was able to follow it:https://www.brighthubengineering.com/diy-electronics-devices/107500-indoor-mosquito-bats-explained/

author: richnormand
author_rank: Unknown
timestamp: July 23, 2020, 10:40:18 pm
content: I have two of these tennis racket type HV zapers. Overall they work great.However two caveats:1) abound the barbie (BBQ) or around food keep in mind that the critter very often will partially "explode" or shed various parts that will land on your food.....2) around electronics I saw my TV remote actually reset the system from the emp when used within about 10cm. So swatting a fly that landed on the remote is probably not a good idea...

author: themadhippy
author_rank: Super Contributor
timestamp: July 23, 2020, 10:52:34 pm
content: Dont be tempted to upgrade your bug zappers to a 63A 3 phase input

author: Red Squirrel
author_rank: Super Contributor
timestamp: July 24, 2020, 01:43:19 am
content: Haha nice, I have one of those and always tell myself I want to mod it to take 18650s and just never got around to it. Easiest is to just wire it direct, but I would want some kind of low voltage cut off or at least an indicator, which makes things a little more involved.Then there's simply completely replacing the electronics with something a little more beefy, like a push pull circuit and nice step up transformer.

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 24, 2020, 07:25:55 am
content: Quote from: Johnboy on July 23, 2020, 07:00:07 pmI've heard of an initiative in Africa that was able to significantly reduce the number of (I think) tzetse in a locality by using low-tech traps. This was in the 70s IIRC, so probably predated zappers (and definitely predated solar panels to drive them).QuoteThe professional ones definitely work. My understanding from a former colleague is that Coca-Cola, who deal with an obscene amount of sugar, have particularly aggressive ones.I think it boils down to the type of tube. The domestic toys that I've seen have some sort of phosphor, I suspect that the decent ones have naked tubes with a gas mixture tuned for a particular spectrum attractive to flying insects. There might be an LED with equivalent effect, but I'd imagine that UV LEDs- particularly the shorter wavelength ones- are currently in high demand due to attempts at sterilization.MarkMLl

author: Zero999
author_rank: Super Contributor
timestamp: July 24, 2020, 12:40:40 pm
content: Quote from: MarkMLl on July 24, 2020, 07:25:55 amUV attracts insects, but I don't think it's good for the type that bite.You want longer wavelength near-UV LEDs, not the sterilising kind, which are no good as insect attractants. Incidentally LEDs are low efficiency emitters of short wavelengh UV, thus are only used in niche applications, where glass and mercury are a hazard. Mercury lamps are much better for most applications. On the other hand, near-UV LEDs are now more efficient than fluorescent tubes, so are ideal for blacklight and insect killers.

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 24, 2020, 12:44:29 pm
content: Quote from: blueskull on July 24, 2020, 08:00:06 amBut should still be adequate once the internal resistance of the crappy "5800mAh" cells I've got lying around is taken into account, plus the drop on the gnat's whiskers the manufacturer has used to wire up the LV end. If the device had been rated for say 3.5V I'd not have bothered.The weakest link is going to be the pushbutton, which looks like it would be underspecced for a TTL signal. Curiously, the HV connections are in nicely braided and impregnated sleeving... somebody really ought to teach these Chinese a bit about industrial design.MarkMLl

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 25, 2020, 01:21:03 am
content: Quote from: Zero999 on July 24, 2020, 12:40:40 pmI read that some are looking at using UVA and UVB LEDs for sterilizing occupied spaces, since UVC can only be used for unoccupied spaces.

author: james_s
author_rank: Super Contributor
timestamp: July 25, 2020, 04:49:43 am
content: I'm skeptical of the efficacy. Does UVA and UVB affect bacteria and viruses? I thought the thing that makes UV effective for sterilization is that it breaks apart molecular bonds, it damages skin the same way it damages microorganisms.

author: MarkMLl
author_rank: Frequent Contributor
timestamp: July 25, 2020, 08:15:46 am
content: Quote from: blueskull on July 25, 2020, 05:16:01 amAlthough I think that it's legitimate to infer that it's going to be higher than from cells which are fully traceable and test consistently.I've got one of those little EBD-M05 battery testers, but haven't really got the hang of it yet. What is supposedly a less-capable tester appeared to show that these cheap batteries lose about 10% of their capacity every time they are cycled, at which point I think I'm entitled to be very dubious about their performance.However, my intended point was that the resistance is probably lower than that of the 2x AA cells being replaced, and probably higher than the 2x D cells I mentioned as having used the last time I did this.QuoteIndisputable, but the LV wiring and switch really are /spectacularly/ weedy. It would obviously be possible to replace the wire with something better, but there'd be little point doing that without finding a slightly better switch... which would be unlikely to fit without a bit of hacking. So this really is a "rabbit hole".QuoteExcept that it doesn't even need insulated wire: it's a link from the PCB to the exposed electrodes held in place by the moulding of the case, so doesn't need insulation.QuoteWell, I did obviously write that with my tongue firmly in my cheek and I can assure you that I have the utmost respect for what the Far East has achieved: I'm old enough to have seen Japan, Hong Kong and Taiwan mature from purveyors of tat although not with the stunning trajectory of Central-Kingdom China, and sufficiently well-read to be aware of at least some of the history.If called upon to make a point, I would criticise not the ingenuity and focussed aggression of the mainland Chinese, but the utter stupidity of Western consumers who let their greed for "stuff" outweigh the money that they were prepared to plough back into their own manufacturing economy, and in particular I would criticise young people whose culture based on "teh shiny" places no value on study so that they can work out how to design and manufacture it themselves.MarkMLl

author: Zero999
author_rank: Super Contributor
timestamp: July 25, 2020, 04:45:02 pm
content: Quote from: NiHaoMike on July 25, 2020, 01:21:03 amQuote from: james_s on July 25, 2020, 04:49:43 amUVA has little impact on viruses. UVB does have some germicidal effect, which is one of the reasons why viruses spread less readily in the summer, but it also causes sunburn, so it can't be used when people are around.