This teardown was interesting, not just because of the circuitry and clever cartridge monitoring technique, but also because it made me look for information on Transfluthrin and how it works.
Transfluthrin is a synthetic insect repellent/killer based on a naturally occurring chemical from Chrysanthemum plants. It has a history dating back to the 1800's.
The chemical works by affecting sodium channels in nerves resulting in rapid effect against insects which are largely controlled by nerve reactions.
It has a low toxicity to humans because it is rapidly metabolised and no significant accumulation. But it can cause health problems if ingested or with high exposure that may have temporary effects on the nerve system.
At this point in time Pyrethrins (of which Transfluthrin is one) are regarded as the safest pesticides with low environmental risk. The common plug-in oil vaporisers usually have the transfluthrin in a carrier oil (kerosene?).
I subsequently did a current test on the cartridge's LR44 cell by slipping a piece of thin card with copper foil on either side between the cell and the contact. That let me put a meter in series to measure the current. In standby no current is drawn from the cell. When running a current of 180uA (0.18mA) is drawn.
I've got another Xiaomi unit on order that is smaller and operates in a different way.
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13 thoughts on “Inside a xiaomi mijia mosquito repeller. including cartridge reset info.”
  1. Avataaar/Circle Created with python_avatars Ipsum the Purple Wuss - Loud Nation says:

    Pronunciation – "Shaomi"

  2. Avataaar/Circle Created with python_avatars Jay says:

    3 years later, looks like an ATTINY13, 8 pin and very usefull, oh and very cheap

  3. Avataaar/Circle Created with python_avatars Robert LaPointe says:

    Your hands seem to have recently lost an argument with a threshing machine. Or have you been playing with Ralf's "happy cats"?

  4. Avataaar/Circle Created with python_avatars Jeff B says:

    Flashing light means it's ready to connect to bluetooth. You need the Mi Home app. Once connected you can monitor the cartridge life time AND also schedule on and off time, and turn on and off remotely (doing this preserves cartridge life, for example we have in the office and it turns off over the weekend).

  5. Avataaar/Circle Created with python_avatars Jeff B says:

    You say it like Shao Me.

    So Sh and then ow, like you hit your thumb with a hammer and then me like yourself.

  6. Avataaar/Circle Created with python_avatars berz menta says:

    good video but without any mosquito caught?

  7. Avataaar/Circle Created with python_avatars Helio Centra says:

    I've always heard it pronounced Shaow-me

  8. Avataaar/Circle Created with python_avatars Plokman040 says:

    To be honest I am always wary of anything that can damage Nerves and your nervous system, not fearfully just very cautious as nervous problems freak me out. Having watched a Uncle slowly loose motor functions from MS was quite eye opening of you take my meaning, Parkinson's is also a condition that I at times sorry about developing. I do currently have a weird problem with my left arm and the nerves inside it, they are all fully functional as my doctor tested with nerve conduction machine pretty much a Fluke for nerves I would love to see you take one apart but I doubt it would be easy to get a hold of items designed for medical services. Then again some of the stuff you have shown I'd never even bother looking for, mainly because I didn't know if was a thing till I watched said video.

    Ah right my arm, well all the nerves seem to be functioning by the tests but my arm feels off like a polarity reversal of something is the best way to describe the feeling. My arm is always weaker than my right and it has far less stamina, my doctor plans to follow up on it with MRIs after this viral thing is done but the only thing I know for sure it wasn't a stroke like so many people tell me when I describe it.

    How do I know, two reasons my brain functions perfectly fine if a bit more Obsessive on phobias at times and two my doctor told me as long as I have had this problem (Granted I only recently found a good Doctor again, most have been far too over taxes by workload or were quacks. Don't get me started on the woman who nearly fossilized my father with his calcium suplements.)if it had been a stroke I'd be dead because without proper treatment strokes tend to cause brain shutdown like a cascading failure in a circuit.

  9. Avataaar/Circle Created with python_avatars Boaz Lips says:

    Whatever happened to that other unit? I can't seem to find the video

  10. Avataaar/Circle Created with python_avatars Michael Bishop says:

    Add a few UV LEDs to attract the insects to the gas chamber zone.

  11. Avataaar/Circle Created with python_avatars BigLoo says:

    "Don't lick this. It's probably bad."

  12. Avataaar/Circle Created with python_avatars matthew Beddow says:

    Transfluthrin is very toxic to cat who cannot metabolize the substance & it builds up , not sure if this device who give high enough level to cause harm but i would not chance it with my Cats . Dogs are different it's not such a hazard in dogs.

  13. Avataaar/Circle Created with python_avatars Lloydie Desu says:

    still working??

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