Fixing a Faulty Xiaomi Mijia Soap Dispenser

In today's video we learn that there always is an a-priori unknown, fixed, positive and non-zero amount of time, effort and money that will, if thrown at a problem - make it go away (at least momentarily).
Overall a success story .. my friend would’ve for sure thrown this out. It has however been very nerve-wracking to work on ..
There were 2 main problems compounding each other constantly
1. corroded battery contacts: with 8 contacts and 4 cells in series, it only takes one weak link to bring the entire show offline; the pump would start, draw 1+ amps for a few milliseconds, that would crash the processor, which would simply reset itself and completely forget it saw a hand
2. this might have been caused by me, but, the IR sensor arrangement is not well designed .. even though it has locating pegs for the IR sensor board, it would constantly see reflections from the shield, which eventually was removed
Weirdly enough I will probably order another one of these for my parents .. I just love the design and honest build .. maybe they even improved it over the year(s)

[@Darieee]

Purchasing link: bit.ly/3gn7N6q [or maybe even try purchasing this locally from a local reseller/shop - in these hard times they need all the help they can get, and the post is insanely slow]

[@barinderpalsingh1397]

I can’t thank you enough mate….mine started to work after I put that rubber piece back ….have been struggling for so many weeks to fix this ….you saved me from getting a new one…. God bless you

[@user-dy9wf7rx1l]

I think you did not need to remove this part, in its absence, the photodiode is illuminated and the controller ceases to understand what is happening, I recently repaired the same device and I want to share my experience with you. To disassemble it, you need to insert two knitting needles from the bottom of the battery compartment and squeeze out the cover, there are many videos in Russian KZbin about this.As I wrote, the controller has a rather interesting program, if you bring your hand to the sensor and hold it for a long time, it turns off, taking it for error. The most common malfunction of this dispenser is unstable operation - most often the reason is the wrong choice of batteries - the most optimal option is to take batteries from the same manufacturer with number 5. The second most common malfunction is drying of the soap at the outlet - because of this, the soap begins to squeeze into the dispenser, which leads to oxidation of contacts, is corrected by rinsing the outlet mixer in water. You can also upgrade it by soldering a 3300F 35v 35 capacitor parallel to the batteries, it is no coincidence that they have a minimum leakage current, which does not affect the battery life, after which the dispenser works even with heavily discharged power supplies. sorry for my english

[@javmat]

Thank you for sharing. Greetings from 🇨🇱

[@natecaine7473]

Mine is a later revision with a single narrow PCB that contains the micro, touch switch, LED, and the IR sensor. Otherwise looks the same from the outside. There are no hoses; the pump and foamer are integrated into a single module at the top of the unit. To remove the top cover, go in thru the battery compartment. Notice that between batteries 1 & 2, and also between batteries 3 & 4, there are oval holes about 2mm x 4mm. I used a long screwdrive that was 2.5mm diameter and over 75mm shaft. Push the screwdriver into each hole from the battery side, all the way straight thru the unit, until t pushes the top cover off. Very easy. You could probably use a stiff length of wire instead of the screwdriver.

[@Darieee]

very nice tip ✌️ thanks

[@wirdy1]

Had 7 of these, different types & styles. Any with batteries in the base just corrode in 6-9 months even with a seal on the battery lid. The best are the xiaomi type with all the electronics above the soap/water. IR daughter board seems a weak point, dry joints & corroded/split tracks as it lives right below the foam nozzle. Had to solder 0.1mm jumper wires twice to fix tracks on mine! It was useful seeing the pulses on the scope, cheers.

[@Darieee]

glad to see I'm not the only lunatic keeping soap dispensers alive 🔥 and - yeah - I also deeply enjoyed seeing the pulses on the scope - I feel so much better reaching my hand under it now that I know e x a c t l y how it checks on me

[@Daemon247]

i fixed mine,by throwing it in the trash and bought a new one.

[@Darieee]

yea .. wish I had such inspiration before shoving 30 hours into mine

[@tomas.medonas]

Great video, thanks. Also I have a better solution of opening it without leaving any mark. Carefully drill a hole on the back of the dispenser on some empty space. Then push some long blunt rod into the hole while it will touches the top cover. Then simply hit several times to the rod and top cover will open

[@Darieee]

that's a pretty neat idea 🤘, thanks for sharing

[@dron2336]

Well I wish I found this comment earlier…

[@VladVeyron]

Love these series!

[@Shahran91]

I was having a similar issue with my own Xiaomi Dispenser. Thought something was wrong with the motor but couldn't figure out how to open it up. This was helpful. Thanks a ton!

[@Darieee]

was it the contacts or the IR blaster ??

[@sahiska]

Instructions unclear, soap got in hair

[@Darieee]

😂

[@0546310344]

hello where i can find the user manual

[@luodun2008]

Thanks for the video, I end up drill a hole at the base and use a long screw driver to push the lid up. The design of the rubber seal is not thuck enough causing it to leak. Need to put a silicon on it to seal it.

[@zbigniewolszewski7097]

Super - dziękuję za filmik pomógł mi w naprawie.

[@christians.5434]

I used a little bit contact spray and a fiberglass brush to clean the contacts. That fixed the battery contact problem for me. No need to open the device ;)

[@jefffrodermann5348]

Very interesting. I wonder if it would have helped to use a heat gun to gradually expand and soften the plastic around the top seal, so that the top could be removed more easily.

[@kanatekriengkraisuk496]

I have same problem with sensor it full with soap after clean it back to work well with out to remove cover BUT!!! After that Motor has Die!!! sensor work the light blink but the other mechanism is quite 😭 have any solution for me? 🤦🏻‍♂️

[@dbuezas]

Thanks for the video, was having trouble opening it. The proximity sensor in mine seems to be busted also. I'll try your same measurements and removing or cleaning the IR channel piece :)

[@Darieee]

yeah, just leave it without the black IR plastic bit on mine it just sits with that rubber light-guide thingy

[@dbuezas]

@@Darieee That didn't work either, It seemed like the transmitter led failed. I ended up throwing the small board away, and plugging two normal 3mm IR LED+Receiver capsules directly to the connector. It still almost didn't trigger behind the black plastic bit so I just drilled 2 holes and exposed the LED capsules. It is very usable again :)

[@aeros3fly]

@@dbuezas hi, could you help me? what 3mm ir leds did you buy? 940nm? 850nm? thanks in advance.

[@Darieee]

I think both should work fine ✌️, as long as you get the module which has both the emitter LED and receiver diode on one board, they'll be able to trigger each other just fine

[@dbuezas]

@@aeros3fly @vcmrco.O I don't even know, I used a pair that comes with a small black plastic divider (i threw the plastic away and used the LEDs). It died after 6 months anyway. I'm thinking about replacing the whole electronics with a custom one as done by @darieee

[@mihailborovik]

Well done. And about such bad plastic - cut edges, fill silicone. Thada! Couldn't see other options.

[@cxxaner]

You should have used two slot near battery holder. Insert gently a piece of thin metal

[@Tumsakari]

Ill teach you a trick to remive those clip things without leaving a mark, get mounting tape and something that is flat and easy to hold, stick the mounting tape to the object with a flat surface, and stick the thing to the part with clips, after its sticking well give it a sudden but fast pull, and it will come off

[@NomadFella]

Same issue, works for half a day and dies out. Any update to fix it? I already checked and its not the contact corrosion issue. Most likely the IR problem. Wondering if applying some sort of coating or electrical tape on the IR shield would fix it. While it works, its just great and i would love to see it work consistently. Few other observations: 1. If you constantly place your hand underneath the IR, then it can detect that the hand is there and the touch led regularly flashes red. Means it transmitter and receiver are working fine. 2. If you leave the machine untriggered for some time, then motor does not rotate in the beginning. But if you activate the IR sensor several times by placing and removing the hand below, then eventually it starts working as normal. This tells me that it might be a capacitor problem which eventually gets charged and provides sufficient current to the motor. But its a wild guess as i don't have expertise in electronics. May be someone more knowledgeable can deduce the solution.

[@Darieee]

hmmm, just remove the black plastic piece, just leave the rubber and try not to spill to much soap into the IR LEDs

[@NomadFella]

@@Darieee I want to keep the IR cover. It sounds like a simple problem and am curious as well as surprised why it is happening and that that the manufacturers have not tried to solve it yet. Please see additional info above that i have added based on my observations.

[@Darieee]

do try leaving it off just as a diagnostics step ✌️ if that fixed the issue then you have to find a way to realign it .. or maybe it's dirty on the inside who knows do let me know if the cover was the issue, I'm quite curious

[@NomadFella]

@@Darieee Tried leaving the IR sensor terminal outside the box in open overnight. Next day it triggered but was sluggish initially. After a couple of times it was fine. There is definitely something related to some feedback over time going on that overloads the trigger.

[@wirdy1]

Design flaw? I think the location of the IR board in a moisture-laden area under the foam nozzle makes it prone to corrosion from the weak acids in the soap foam mist. Also the rubber masking boot that prevents crosstalk from IR Tx/Rx LED's holds moisture against the board. There are some test pads on the IR pcb that appear to corrode faster & the corrosion gradually creeps under the solder mask & eventually break the tracks. Whole IR board should be potted for longevity, but that would cost extra $$'s at manufacture.

[@PsychPatric]

Hey Darieeee, I must say: Your device worked longer than ours. Ours just lasted 2 months. However, I can feel your frustration! Especially the last attempt :D I hit our plenty of times 😂

[@Darieee]

yeah, maybe this summer I'll muster up enough courage to order another one XIAOMI does tweak stuff constantly .. but .. a closely related version (bought only half a year or so later), also died because of water ingress 🙄 it was quite a bit reworked inside though ...

[@PsychPatric]

It is fantastic to know that there is a person out there, just like you, answering my questions in regard to whether XIAOMI’s engineers are just giving up or not… obviously not lol 😂

[@PsychPatric]

You should send them an email with Tour Videos … maybe thats a good Feedback for them improving it after all

[@jgym8036]

There’s a catch at centre of the back of top cover u juz hve to use a simple flat scrapper to open it with only a very slight unnoticeable scratch

[@146akshat]

I love this thing but it eventually stopped working. The light turns on and off but pump motor does not work. The proximity at which the motor turned on kept on increasing and one day motor stopped working. I think the IR sensor is the culprit.

[@Darieee]

yeah ... a highly and broadly flawed design ... prettiest one out there tho .. I will say .. bought a baseus one recently - seems better built

[@Aduck79]

@@Darieee I just disassembled a Baseus today, and the insides is the same as yours. I bought 3 of them, and just returned 2 with the same flaw, turns on but doesn't pump.

[@wirdy1]

@@Aduck79 take a look at the IR circuit board under a scope. There are test pads on the board that seem to just corrode away & break the tracks. If you are okay at fine soldering 0.1mm wire, the tracks can be jumpered & fixed, but it takes a steady hand and a microscope.

[@javmat]

Great video. I really appreciate, first, the amount of time you put into the solution. And second, making the video and sharing with all of us. Interesting how a beautiful product and design (visual) has these flaws. Coming from Xiaomi. Greetings from the south of the world 🇨🇱 Thanks again for sharing.

[@Darieee]

glad to know people appreciate it ❤️ it's dead again btw .. so, comments like these really motivate me into making more videos on it

[@javmat]

@@Darieee thanks to your video and some comments I could fix mine. Mostly how to open it. Mine was very dirty with the leaked soap. I cleaned it deeply and put it together again. It's working (for the moment 😅). I saw new design on aliexpress that will be my next dispenser, one that goes installed on the wall. Greetings my friend 👊🏻

[@user-ki7zg5fx5j]

Pain in the ass to open the cover up

[@affankhanster]

Hi a question

[@affankhanster]

If I supply 5v dose it work

[@PsychPatric]

To everyone else watching this video: bear in mind it hast thousands of views, which only means we are not alone with this piece of shi**t … whatever they sell its obviously working well 😂😂😂

[@nonamenoname1645]

We should all file a complaint with this manufacturer obviously items have a malfunctioning issue company won't stand behind their product from China August 2023