Capacitive Soil Moisture Sensors don't work correctly + Fix for v2.0 v1.2 Arduino ESP32 Raspberry Pi
ฝัง
- เผยแพร่เมื่อ 14 พ.ค. 2024
- In this episode I talk about capacitive soil moisture sensors and why 82% of them dont work correctly. I analyze the 3 most common problems they have by design and show you how to fix them or how to find sensors that work right away.
You can jump to one of these sections:
0:00 Introduction
0:39 Flaura - the smart, self-watering plant pot
1:20 Resistive sensors suck
2:03 Working principle
2:43 Learnings from 38 orders
3:47 Missing voltage regulator
5:11 Wrong timer chip
6:57 Missing resistor connection
9:39 Fixes
10:01 Ordering advices
This is the fourth video of my tutorial series on how to build your own “Flaura”, which is my Do-It-Yourself, Open-source project.
Flaura is a smart, self-watering plant pot that comes with the following features:
- 3D printed housing
- Integrated water tank
- Soil moisture measurement
- Automatic watering
- Rechargeable battery
- Arduino Code
- App control and data display
- Push notifications
Consider watching the introductory video, to learn more about the features and my future plans with Flaura: • Flaura - Automatic, Sm...
I will release more step-by-step video tutorials here in the future on how to build such a plant pot yourself. Stay tuned! 😉
Music Credits ___________________________________________________________
Song: Jarico - Island • Free Background Music ...
Music supported by #BackgroundMusicWithoutLimitations - วิทยาศาสตร์และเทคโนโลยี
So where have you had your best luck purchasing the moisture sensors at?
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.
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.
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 🙂
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!
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!
Unglaublich tolles Projekt. Ich freue mich schon auf den nächsten Teil. Weiter so!
Thank you for this video.
I knew my sensors needed the resistors, but never knew exactly why.
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!
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.
The world needs more people like you! Thanks so much!
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
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.
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
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.
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.
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.
I saw it afterwards only to find out how lucky I was with the one I got xD
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.
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.
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!
Just don't rely on product pictures. They display a TLC555 with regulator and send a NE555 without. After these lessons learned, I modified my soil sensor to have a 5V boost converter to power the soil sensor.
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!!!
Brilliant, thanks so much for laying this out. Provided HUGE insight to explain why my project is failing with these sensors.
Really appreciate the effort which you have put in creating this video. Thanks for sharing this.
Both my 1.2s were missing the 1M resistor, thanks for a great explanation of why and how this caused the error!
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.
Great! Thank you so much for pointing out these faults! It's a headache what some manufacturers do to save a few cents.
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.
Mega Video! Ich bin kurz davor mir ein paar Messgeräte zu basten, da sind die Informationen echt Gold wert! Danke.
Thanks for this video. I purchased 6 sensors and ALL have all the faults mentioned in your video.
Great video! In my (very limited) experience this problem occurs with a lot of sensors, not only soil humidity but also temperature, air humidity and more.
What a great video of investgative journalism in electronics field, what a story!
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!
Well done! Matches my experience. Resistor not connected in any of my sensors
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!
Hello, i tried using the 5V of the arduino board and still can't make it work, how did you make it work?
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...
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.
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!👍
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 :-)
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.
Also, powering it with ac would probably help
Do you know links showing how to modify it?
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.
bingo!
Measure your sensor with alternating current - turn one pin high and the other low, then next measurement, reverse the two pins.
Thank you for your detailed and methodic work. The 1M resistor not connect… wow 👍
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".
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!
Thank you, I've got 6 of them and all have the grounding error. Thank you for saving me a lot of time for troubleshooting. :)
Thanks a lot for having found a broken PCB path to the ground! Great job!
Man I love the detailes of your video! You are a white hole of information! Great :)
2 pieces. v1.2 - both with all 3 faults. local retailer, berlin. thanks for saving me lots of frustration and time. this is unbelievable.
Thanks mate! I just ordered 100pcs for a big project to a vertical farm. I guess I need to make more tests before deployment.
Thank you for your time and dedication, great video, you are the boos!
Thank you for pointing that out. As it turns out, the unflawed version is extremely hard to find...
I got the same wrong hole position, slow respon reading, your video explain it clearly.
World need more people like you. May Allah blass you and give you hidayah 👍
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
This is nice and comprehensive. Thanks for the hard work
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.
Thanks so much. I was searching for this issue since weeks :)
I was lucky to get the right ones. Thanks for the video
Great explanation! I'm facing the same problem here, unfortunately, I watched a little late.Thank you for the alert!
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.
A very useful video, thanks so much for doing this work. Would you care to list which vendor(s) sold the fully functional sensors? That would save us a lot of time. 😉😉
Very helpful video - has saved a lot of hassles - many thanks
Thank you so much for the information! It's really saved me from future headache because i just going to do project with this type of sensor.... This is a very helpful video
Thanks for the overview 👍
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
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 🙏
What was the right one?
Please tell us the good one. I got an entirely defective pack.
very nice video! My two v1.2 sensors have an NE555-93M, a thru hole on the side but a present 1M ohm between G and Aout, and a 0ohm resistor instead of the voltage regulator. I have not used them yet but this video was very informative. Now I know what to expect. Thanks a lot.
i'm very grateful about your video, it has make me take a more informed decision about which sensor buy, again thank you.
Thanks so much for doing all this research!
great work! thank you for sharing informations and may the force be with you
Thanks a lot for sharing. I'm gonna have to do some wiring on my "2.0".
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 !
Thanks for the video! I used the tips provided when shopping on Aliexpress
Great work... thank you for the heads-up.
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.
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.
Thanks for sharing this easy way to determine whether the sensor is faulty. My sensor has the 662K, the correct vias placement, but unfortunately, it has the NE555.
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.
Thank you for this super helpful guide!!
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.
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
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.
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?
Thank you so much! I learned quite a bit from this.
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.
The LDO could be a problem if you plan to power it from 3.3V, though. If you're using a 3.3V MCU, the one without LDO might actually be a better choice (assuming you're aware of it and use an external regulator).
Danke für das hilfreiche Video. Super. In die Falle bin ich im Frühjahr 2021auch getappt - und habe mir in Kombination des Feuchtesensors mit dem Calliope Mini mit Parallelschaltung eines 470k Widerstandes und eines weiteren Kondensators geholfen, da ich die hohe Eingangsimpedanz des analogen Eingangs im Verdacht hatte.
Very helpful information. Much thanks.
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.
Thanks so much for doing this research- returning my recent purchase from eBay and paying a little extra via a reputable dealer for the right part.
Thank you very much for these great tips&tricks. I have checked my sensors, and discovered that they have issue no. 3. Thanks to your video, it can be easily corrected with one wire or resistor.
Mine as well
Amazing work and very useful
Thank you very much for this great clip !
Why measure on R4, according to the board, and refeering to R1 in the schematics, regarding no connection to ground?
Great research. Well done. Thankyou.
Excelent video. I like it a lot. Now I am planing to messure and control of humidity of growing seeds. I worked in the oil industry some time ago. I designed and got a patent to messure the water content for a mixure of water and oil in a pipe. In other words, an online water content analyzer. I am a physicist, and worked with an electronic engineer in that proyect. I really apreciate your work. Now, many years later, I am involved in this similar problem, but in this case is a mixture of water and soil. But this is kind of a personal proyect.
Very cool Fernando! 🌞✨🌎😊
Design one that works correctly and bring it to market.
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.
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.
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
What is a "bard edge"?
Huge appreciation man.
Thank you for your findings. I have a few and I found two of them with the same version number (20190515 HW-330) but they are different. They both have the issue with the 1M resistor but one of them has a voltage regulator while the other doesn't.
I also have a few with the same hw version 330 but a different date. The date on the pcb is 20210603 and they are fine. The via hole is on the same spot with the faulty boards but the right pad of the R4 is connected on GND through other vias. There are four more vias on 20210603 compared to 20190515.
Thanks for the information. I was looking at several of these boards, and many show a TL555C (as opposed to TLC555C). Looking at a datasheet from Texas Instruments, it looks like these are the same, just marked differently. Before I buy any of these, I wanted to check with you to know whether you found any difference in how these timer chips operate.
THanks, I have six sensors here I now need to check.
Thanks mate really helped me! I ordered one from Ali for less than a dollar so if this one is faulty I'll try a more reliable retailer in EU.
Thanks! Great quality content :)
Thank you for this video. It saved me from a lot's of trubles !👌