Capacitive Soil Moisture Sensors don't work correctly + Fix for v2.0 v1.2 Arduino ESP32 Raspberry Pi

[@ThePhaaze]

JACKPOT: I've hit all 3 problems with the first ordered sensor! The fix i'm going for: Throw it in the garbage, order a new one. Thanks for the video.

[@Humbulla93]

Get a blumat moisture sensor it's better in all aspects and most accurate

[@agent_artifical]

@@Humbulla93 i agree, but i still want to monitor to home assistant or iobroker

[@Humbulla93]

@@agent_artifical I have a solution but I'm not tech savvy enough to implement it. The solution: use a camera module with a picture recognition module and couple it with a relay for a water pump. When the correct number is shown the relay gets activated for a fully automated watering

[@agent_artifical]

@@Humbulla93 might be an option but i rather would open the sensor and connect an esp directly to the pins to monitor the values. Its to much hustle in my opinion but also will require much more energy to work and will not work properly during lights out

[@robinharris4706]

I did some work with soil moisture sensors a while back and agree, resistive are useless. So I tried a capacitive one but got unreliable results and moved on to other projects. After watching your video and the excellent research behind it, I checked my probe. Yes it has the missing resistor connection! Now I now why it didn't do the job and am about to go and fix it. This opens up an old project - thank you 🙂

[@jim5148]

I got lucky. A few months ago I bought a bag of these and they are labeled v2.0 / HW-390, and they have the 3 terminal regulator and the TL555 chip. Despite having the via at the lower position as shown as the Faulty board at the 8:00 minute mark, the 1 Meg Ohm resistor indeed appears across pins 1 and 3 on the connector. I didn't scrape off the solder mask to see how they made the connection, but they did somehow. Thankfully the one I tested provides stable readings from ~200 submerged, to ~515 dry. It also works on 3.3 VDC, providing the same readings as when powered from 5 VDC. Thanks for the good video!

[@milutzuk]

That's right! Have the same sensor, v2.0 / HW-390. The 105 resistor (1MOhm - 10*10^5) makes the connection between AOUT and GND, even if the via seems to be at the wrong position. It can be checked directly on the connector pins with an ohmmeter (I waterproofed my sensor and I didn't want to destroy that to touch the resistor's terminals)

[@erdbeeren3241]

Pretty important information: for those who want a more sensitive moisture sensor, you can bridge the 1MOhm resistor with a 100kOhm one. The default output value changes a bit but the sensor reacts on raindrops for example. Same probably goes if you have the faulty connection.

[@SoggyCashew]

So where have you had your best luck purchasing the moisture sensors at?

[@Arduino_and_Redstone_Nerd]

I got mine from berrybase. It has everything right, I checked it. Hope I helped :)

[@Humbulla93]

Get a blumat moisture sensor and enjoy the trouble free action

[@Arduino_and_Redstone_Nerd]

I got mine from berrybase. It still works perfectly after 2 years:)

[@torquebiker9959]

@@Humbulla93 Stop spamming plz

[@kumd]

Extremally helpful! So glad I saw this before ordering. I can't thank you enough for devoting so much time and money to make this video. It's truly appreciated.

[@claudiodyus211]

I saw it afterwards only to find out how lucky I was with the one I got xD

[@wileymarm0t]

Thank you for making this video. Not surprising, these capacitive soil moisture sensors are still being sold with the same problems you mention in this video.

[@Swisstechguy]

Thank you so much! I just got a batch of 10 faulty sensors. R4 is not connected to GND. Remark: in the schematics you are showing the resistor is wrongly labled R1; correct is R4

[@Funky3Player]

Just a heads up if you already have a resistive moisture sensor. You can just pulse it's power on each measurement with a transistor/digital pin and prolong its life substentially. I've had mine running for over two months with no sign of dissolvement.

[@m.sierra5258]

Also, powering it with ac would probably help

[@eaglehigh-h3e]

Do you know links showing how to modify it?

[@SetTheCurve]

Pretty sure that Ecowitt sensor must do this because they stay accurate for years and the single AS battery seems to last about a year, even though it’s also powering a radio.

[@imbass8151]

bingo!

[@moeburn]

Measure your sensor with alternating current - turn one pin high and the other low, then next measurement, reverse the two pins.

[@SmoothSkySailin]

The world needs more people like you! Thanks so much!

[@RND-USA]

Oh no! Mine just came in the mail. Voltage regulator ✅, TL chip ✅, hole in correct place ❌😕 Thanks for all the thorough testing in this video. Now at least I won’t drive myself crazy wondering what’s wrong.

[@robinharris4706]

Further to my comment yesterday - I applied the easy fix and it is working perfectly. Brilliant - thank you for sharing the results of your work - you have helped me greatly.

[@shahnewajx]

I bought 50 of this sensors. Didn't know what's the problem. I was looking for video like this for 2 years. I can find only one video which shows 1m resistor problem from "Stewart Cash" . But this one is epic.

[@hughweld9561]

Thanks for this video. I purchased 6 sensors and ALL have all the faults mentioned in your video.

[@maro9282]

I just ordered few Capacitive Soil Moisture Sensors, to create a smart home system for tracking all the plants in the house. Thank you for this video! It's super informativve and helpful. I hope the sensor will come working, because it looks on on the pictures, but you never know. I know what should I look for and how to check what may be the problem. Thanks a lot!

[@LVHeitor]

Outstanding expanation about moister sensor tricks that I was never imagine to find... Tks

[@Dartheomus]

I was just about to jump into buying a bunch of these, so I'm so thankful you took the time to investigate. This was exactly what I was hoping to find. I didn't feel like finding out the hard way! Nice work!!!

[@planker]

Well presented. Good solid information, I have a few on order. My first time with such a sensor and did all the work to receive it and apply it to my build. Had I NOT known about the 3 problems, I would have blown a gasket. Thank you.

[@jurerepina]

My sensor just arrived and all is well. Without this video, I wouldn't even know what to look for when purchasing, and indeed it was really hard to find the right one, especially on Aliexpress. Thank you for bringing this to our attention 🙏

[@AtlantaTerry]

What was the right one?

[@PokemonTrainerAriel]

Please tell us the good one. I got an entirely defective pack.

[@emesma]

Please, provide the link you purchased from. Thanks.

[@subratasaha1312]

A very detailed and easy to follow video, highlighting the flaws on the sensors was invaluable, thank you for your time and effort I really do appreciate it.

[@simonandrews9629]

Brilliant, thanks so much for laying this out. Provided HUGE insight to explain why my project is failing with these sensors.

[@davideyt1242]

very nice! thank you for this video, there are a lot of DIYers in this sphere who probably do not have the technical knowledge that you have, and would have never figure out why their sensors fail to function under pretty normal conditions, thank to this information video they now can see if they have a faulty sensor - hopefully maybe some of the manufacturers of those sensors will also figure out that saving 20 cents is not worth losing thousands of unit sales. I'd also assume that the customer will rather pay an extra 50-60 cents and get a proper sensor with the proper timer chip and no missing voltage regulator or resister connection

[@szjoin992]

Thank you sooo much for this video! I thought I had two 'ok' sensors. Turned out that the resistor was not connected and therefore the sensors were very unresponsive, as I already noticed during my project (but taken for granted). Now I was able to fix it. Without you 'I'd never have known this and my projects would be flawed forever! THANKS!👍

[@familyplans3788]

great video thank you and subscribed , i just ordered 10 of these sensors of Amazon and looked at the product page after they arrived, the product page has the wrong boards on it!! After inspecting the sensors when they arrived i found ( to my delight) that they were different !! The ones that arrived had all the right components BUT have the off centre hole , so i did the multi-meter trick you did between ground and the resistor and i got a connection!! I have yet to set one up but fingers crossed it works as expected

[@DejanGjorgjevikj]

Great job. Nice that you have shared your findings with the rest of us. I have checked my 4 sensors and found out that they all have a LDO, and a proper timer circuit (3x TL555, 1x ICM7555) two of them have the via punch hole aside the resistors, but only one of them has the problem of the resistor not being connected to GND. I investigated the PCB further and have found out the actual position of the via hole (that actually takes the signal from the other side of the resistor to the other side of the board where it is routed to the AOUT connector) is not directly the problem, but rather the very tiny lead on the PCB (or the absence of it) that goes under the mentioned via very close to the bard edge that is missing on one of the boards.

[@FlauraSmartPlantPot]

great job too! thanks for your effort and pointing that out. Maybe you can share with us where you ordered the good ones, as many people (including me) struggle to find a good source.

[@DejanGjorgjevikj]

Photo with the the difference in the PCB that causes the missing GND track. drive.google.com/file/d/1-E5Wk0oXwc_SqPuffyOVGcj7iQuNeSLt/view?usp=sharing

[@AtlantaTerry]

What is a "bard edge"?

[@minime9400]

A power saving tip: If the sensors power usage is within your MCUs IO pins power output, connect Vcc to a IO pin, turn it on (with possibly a delay), do the measurement and the turn it off. For my sensor I use a delay of 350 ms from power on to read, otherwise the sensor won't stabilize and the reading will be off. This will of course vary, you have to try it out for yourself.

[@JensJackowski]

this is verry importent. but not only for power saving - all corrotion needs power to take place and by doing what you suggest you will enhance the useagetime of your sensor.

[@thekitsunedev_hun]

Great! Thank you so much for pointing out these faults! It's a headache what some manufacturers do to save a few cents.

[@ultrafilipsz.5827]

What a great video of investgative journalism in electronics field, what a story!

[@rodcoles]

So i just bought 25 of them from AliExpress, of course they do not work. I found that the TL555 chip was in the wrong way, so I had to remove and resolder, i then found thanks to your video a problem with R4 and C4, in my case it was the return to analog reading pin (yellow wire) that the via had broken, i scraped back a bit of the solder mask and bridged it with solder. Now it's all working, but that's a lot of work to do on 25 sensors!! I appreciate your help, I don't think I would have found by myself!

[@sam_fujiyama]

WOW, great video... thank you for the time and effort putting this together. I'm new to these sensors and couldn't understand why many of the reviews mentioned wild variation and unreliable measurements. I also saw the 2.0 version and thought... surely the 2.0 version will be better and fix these issues. Your video answered all these questions. Thanks again.

[@PixelPenguin647]

Thank you so much for taking the time to explain all of this information. Super helpful as I'm looking to make some basic sensors for my plants.

[@spcutler]

Thank you! Sensors I got just a couple of weeks ago *still* have the output resistor problem. You just saved me hours of debugging. A bodge-wire later and the sensors work perfectly.

[@fredberghoff9917]

Thank you very much for your in depth analysis and fact finding on these sensors! As i watched the video I looked at some of these sensors on AliExpress and indeed, they were missing the voltage regulator as you stated. Very good work!

[@wchen2340]

2 pieces. v1.2 - both with all 3 faults. local retailer, berlin. thanks for saving me lots of frustration and time. this is unbelievable.

[@oscargbl]

Gracias por compartir esta información, en mis sensores el problema estaba en la resistencia 1M, pero ahora ya lo he podido solucionar. Me has ayudado mucho 😉👍

[@ruimvfigueira]

Thank you for this video. I knew my sensors needed the resistors, but never knew exactly why.

[@jenniferp3721]

I just bought some of these sensors a few days ago. Wish I had seen this video before hand. However thankfully the sensors I received pass all the checks. TY for the info.

[@Knalltuete0815]

3 Jahre später und das Problem besteht noch immer. Ich hatte "Glück" und musste nur den Widerstand mit Ground verbinden. Danke für dieses Video!

[@fhx1274]

Bought 5 sensors a couple of years back and they have the regulator and a TLC555I, but the resistor is not connected with the same via issue you showed. I'm going to fix them all with a small bit of cable to connect the existing resistor to GND. Thanks a lot for your video, you saved me a lot of time and frustration !

[@roguesecurity]

Really appreciate the effort which you have put in creating this video. Thanks for sharing this.

[@MathPiSG]

What an excellent video. I was checking on my capacitive sensor as I watched you show each of the three types of issues. Sure enough, my sensor checks all three issues!

[@christoffer5345]

I just spent 3 hours troubleshooting why the sensor did not work with my 3,3V Arduino mini battery setup. It did have the NE555 component and was not working on 3,3V. Thanks for making this video! I would have spent days troubleshooting this!

[@chaoticsparrow3581]

Hello, i tried using the 5V of the arduino board and still can't make it work, how did you make it work?

[@DaxterPSP]

Unglaublich tolles Projekt. Ich freue mich schon auf den nächsten Teil. Weiter so!

[@xinhood]

Oh wow, I have had several of these. I had a couple non-working ones with a missing voltage regulator. The ones I am using now have the missing resistor to ground connection, but I didn’t even know they were faulty because I never had a good one. Interesting to learn how they are supposed to work!

[@christianvogel6354]

My second question: In your repair instruction you solder a bridge from R4 to GND. Why? In the wiring diagram the connection is missing between R1 and GND. Or am I wrong?

[@adistef]

I have the 1.2 version with the voltage regulator, with TL555 but NO CONNECTION to ground from the 1M resistor; I didn't even knew about this issue until I watched your video. Many thanks!

[@Colololp]

Wow very Helpful Thank you. You saved me years of Troubleshooting 🙏🏻

[@johncrunk8038]

Very frustrating. I bought a couple dozen of the ones with the missing resistor connection. Although soldering a resistor or jumper is just annoying, that was good money down a hole. Thanks for the fix.

[@agustinberguecio8939]

I have all 3 problems! I will have to buy another. Thanks for the explanation and for taking the time to test them all, I've been trying to get reasonable values ​​for a long time

[@homecasita3886]

Thank you for your time and dedication, great video, you are the boos!

[@edvinmalm5972]

Both my 1.2s were missing the 1M resistor, thanks for a great explanation of why and how this caused the error!

[@ematejowsky]

Thanx. All my sensors have needed a resistor - I used 15K. I also have a temperature co-efficient of around -0.2% per Deg C. I've started to uses 24Hrs averages and water twice a day.

[@RubenKelevra]

8:16 I got 4 sensors which has the hole in exactly this place, but the ground connection is fine. :)

[@adrian30497]

Super Video i wonder Always why i have such Problems with this now i have the explanation

[@greggord-hume3979]

I am also building a smart pot and I noticed my soil moisture sensor values were not consistent due to the reasons you have explained. Thank you. At least i know im not going crazy. Its the downside of DIY projects that the modules are usually garbage quality, a real pity.

[@pwaggie]

Great Video and I use these all the time, I am a little confused why the 1M resistor on the circuit diagram is marked as R1 and R4 on the circuit board?

[@cristovaocardoso1316]

Great Video. I just realised that i managed to buy 1 sensor with the full 3 defects. Thanks for showing them and how to solve them.

[@torbendury3897]

Thank you for this video and pointing out the design flaws of some batches. This really helped me sourcing some working sensors. Tip: Some sellers on Ali are blurring out the name of the timer chip. I guess they also saw your video :-)

[@johnjendzurski3242]

Very clear and informative video! I wish I had watched this before purchasing, but it was still very helpful in troubleshooting the problem with the defective sensors. Mine did not have the voltage regulator, so I will be returning them and trying another vendor...this time paying close attention to the photos! Thank you!!!

[@coolaboris]

Why measure on R4, according to the board, and refeering to R1 in the schematics, regarding no connection to ground?

[@konstantinklementiev8684]

Thanks a lot for having found a broken PCB path to the ground! Great job!

[@ichdu5317]

My first order from a German supplyer was with NE555 and without voltage regulator. The second order (called V 2.0) I made at AliExpress and everything seems to be fine. None of the faults you metioned could be found. But it didn't work! I meassured a constant voltage of 0.733 V at the output anyway if the sensor was try or dived in water. Finally, I was wondering that in all pictures I could find the TL555I, TLC555 or NE555 label was readable but on my sensors it was upside down. And indeed, by measuring and comparing with the schematic I found that the part was mounted twisted. On all 10 sensors I bought. It is really incredible which faults on such a quite simple part can be made. Best, Uwe

[@davidbeck1183]

Well done! Matches my experience. Resistor not connected in any of my sensors

[@rodrigodemarchi1184]

Should've watched this before, as I just found out the sensor I bought has all the three flaws mentioned.. Thanks for the heads u.

[@lyrag6376]

The main problem I've noticed with these types of probe-style moisture sensors is that they lose accuracy with time as the soil compacts around them and water channels along their surfaces, artificially lowering moisture readings as the damp soil is further from the electrodes. Your implementation with the probe being inserted through the bottom of the soil looks like it would solve some of those problems, but you want the moisture reading of the shallowest soil, which doesn't necessarily correlate with that of the deepest soil. I've designed a few resistive fluid conductivity sensors using cheapo platinum-coated EC probes, which can be driven with AC to reduce polarization and can pretty easily be integrated into microcontroller projects, but the problem of ensuring consistent soil contact still stands...

[@jhonatancock2302]

What about surrounding the sensor by some media that wets but don't compact much, some sort of "ideal soil" . I'll start by testing things like porous wood, sponge type material or even solid cardboard.

[@itablet7493]

Thank you for your detailed and methodic work. The 1M resistor not connect… wow 👍

[@ahahfilip5709]

Man I love the detailes of your video! You are a white hole of information! Great :)

[@ManishMoorjmalani]

Huge appreciation man.

[@ObsequiousV4]

This is nice and comprehensive. Thanks for the hard work

[@youpattube1]

Thank you for this detailed video. I followed your advice and ordered 3 different ones on ebay. But forget reading the chip number, or spotting a tiny hole (at least in the images i had to look at). Still, i did my best and we'll see.

[@YISUS_CL]

i'm very grateful about your video, it has make me take a more informed decision about which sensor buy, again thank you.

[@learningmanagementsystemlm2552]

Thank you for the sharing information, good to know for my research project related to this sensor.

[@flaviojmsouza]

Great explanation! I'm facing the same problem here, unfortunately, I watched a little late.Thank you for the alert!

[@michaeldraper8917]

Very helpful video - has saved a lot of hassles - many thanks

[@MachuBaxter]

Thanks for the video! I used the tips provided when shopping on Aliexpress

[@manoelbrasileiro1127]

Very clever analysis.

[@philippm3484]

Thanks for the overview 👍

[@mackenzeighfisher5835]

Great video! For those of you that wanna know more about the topic there's a good overview of various soil moisture sensors in elektor magazine that was just recently uploaded. It's called 'Moisture Sensors for Watering Systems' by Peter Tschulik and is pretty instructive

[@mischavandenburg]

Thank you, this was a really good tip!

[@asarilkima]

Thank you for gathering all that information and sharing it! I just checked my sensors (got 2*6 just today), and found a whole bunch of random samples o.O I got v2.0 which do have the correct regulator, the TLC555I and the disconnected copper trace, but also have two additional vias between the VCC and AUOT [sic] labels, which connect the ground plane in the lower right corner to the GND pin on the bottom side. This means the 1M resistor is connected and working. Mine have a date printed in the area that was scratched off in the video, "20210603". However, I just noticed I got a bunch of random samples in that one delivery, some having a date of 20190515 and those do NOT have the additional vias and are faulty. out of the 2 bags with 6 each, one bag had 3/3, and one had 4 good ones and 2 faulty... so ordering in bulk does not guarantee working sensors. The difference is even visible in the raw voltages, with all good sensors outputting almost the same voltage in air, and the faulty ones also close together, but on a slightly higher voltage. So if someone has two groups in their data when the sensors are just hanging in air, that can also be a sign to go check. And one additional quality issue: One of the supposedly good ones read a constant 0V. That one does not have a regulator at all. Looks like it was soldered but broke off.

[@kwjuga]

Same here. Got the v2.0 with date 20190515 and missing the resistor ground connection.

[@bid0u12345]

Oh, I just wrote the same regarding the V2.0 sensor from 03/06/2021 but without the technical explanation. Yes the hole is misplaced but it's working just fine, so they fixed the issue in the end. This hole place is not relevant anymore. I got lucky, bought a bulk of 8 in August 2023 and all of them are from 03/06/2021. 🤞

[@thomasesr]

I learned to design circuits in Falstad, learned to use KICAD PCB and order a PCB in JLC with the components pre soldered

[@eugenvilin]

Thanks a lot for the video! Half of my sensors didn't had connection of 1M resistor. What I've also noticed: there are good modules having "that via" not between R4 and C4, but near them same as bad ones.. BUT there are additional vias (near the socket and 555) on the board that connect R4 with GND. It looks to be a "fixed" version.

[@TomTom-ty5ej]

Thanks mate! I just ordered 100pcs for a big project to a vertical farm. I guess I need to make more tests before deployment.

[@nicolaschollet7435]

Amazing work and very useful

[@gregwoolley]

Very helpful information. Much thanks.

[@GrahamJones]

Thank you for all the effort you put in to researching this - it saved me a lot of trouble! I wondered how you have found the monger term stability of these devices? I find they tend to start indicating high until I remove them and clean them, then the indication drops - I wonder if it is some sort of biological film grows on them over a couple of weeks?

[@JensJackowski]

i think it is important to understand that most of the sensors have corration problems when you try to read them. If you just put them in the soil and do not have any power on them they are much more stable to use. The main problem is that most people try to read the soil- moisture more or less all the time or every minute - but their is no need for that. 3 or 4 readings a day are more than enough. And the other problem is that many people did not understand that soil is reacting verry slowly. If is a verry bad idear to try watering a plant and use a soil sensor to stop the watering. It takes time for the water to spread in the soil. So what you should do is starting the watering if your reading shows a value that make it nessesary and stop it after a reasonable amount of time. After one hour or so you can do another reading and start a new cirkel if this i nessecary - and you do not have to read all the time. It took me a long time to understand the importence of this point. Its mabybe more important if you are watering a bigger amount of soil than just a plantpott, but basicly it is the same. The water needs time to spread in the soil. I have a bunch of devices that i have build several years ago with those sensors that you describe som just crab. Yes in the beginning i needed to replace them after a few weeks. But since i changed the reading metod and just do a reading every 6 hours are they working without problems since 3 seasons and up till now the do not show any sign of corrotion.

[@syncopium]

I was lucky to get the right ones. Thanks for the video

[@leno6019]

Super Video. Ich habe mir letzte Woche 5 solcher Sensoren bestellt und habe unbewusst das gute Zeug gekauft. Trotzdem danke für das Video. Der Workaround war gut.

[@ngoquanguc1807]

You deserve a like from me, sir. Damn, for a long time i was wondering why my sensor is so unresponsive. All because a faulty design

[@_wildsec]

Thank you for pointing that out. As it turns out, the unflawed version is extremely hard to find...

[@karlosss1868]

Very helpful.... Thank you

[@lorlimann]

I ran into an interesting problem with these capacitive moisture sensors. I wanted to connect 3 of them to a single Arduino. When I tested the system with only a single sensor connected everything worked as expected, but as soon as I hooked up the other sensors, their reading would always influence the output oh the others. E.g. I had two connected and took a reading of them in air: basically the same output. But then when I placed one into water, the output from the other one would also change. I got sooo frustrated by this! I’ll check them for what I’ve learned in this video, thanks!

[@oldmanbluntz]

Write your code so that the arduino staggers the reading from the 3 sensors, and have it turn on one pin per sensor only when its reading turning it off when its done reading. This should help with crosstalk over the channels considerably.

[@lorlimann]

@@oldmanbluntz thank‘s for the advice!

[@oldmanbluntz]

@@lorlimann i discovered the method when i was testing this with resistive moisture sensors, and testing different things to reduce the crosstalk. I'm sure there is some DIY hardware filter that could also be made, but i was looking for a simple solution.

[@Welshwizzard1]

I had 5 of these boards order this week, when I checked them they were all good, phew !.

[@ftnavy123]

Thank you so much! I learned quite a bit from this.

[@DO2VI]

Danke Martin, das war ein sehr hilfreiches Video. Ich habe so einen Sensor mit dem 1MOhm Fehler. Und kann ihn nun dank dir doch nutzen.

[@dronefootage2778]

7:55 not the silk screen but the solder mask 8:10 not wire hole but via

[@the_smart_home_maker]

Thank you for this super helpful guide!!

[@PhilR0gers]

I have tried following this advice by looking at the pictures of the sensors, but from 3 vendors so far, the sensors that they send have not matched the pictures. For example, I can see that the hole between the resistors is in the correct place, but when they arrive, the holes are in the wrong place, so it's a bit of a lottery when you order them. I even had some arrive that were labelled "Capacltlve Soll Molsture Sensor v2.0".

[@michaelatzenbeck6575]

Thanks so much. I was searching for this issue since weeks :)

[@bengrantham8966]

Great research. Well done. Thankyou.