List of timer chips that (probably) work on 3.3V: - TLC555C - TLC555I - NE555 20M - NE555 41K - NE555 21K Feel free to reply to this comment if you find another working chip, and I'll add it, so this comment can be a resource. Main comment: This is some seriously great content. Since this is such a resource to the community, I'd like to contribute to it. I bought a v1.2 sensor with a NE555 41k, which works wonderfully with a 3.3v output pin on an ESP32. I watched this video way back, then recently just bought the cheapest sensors I could find without referring to this video, so I was kinda bummed out when I looked at this video afterwards and saw a NE555 chip on the sensors. I decided to try it anyway, and they work flawlessly. The only really dumb thing is that the ground and VCC wires are swapped on the connector, which made me think the sensors didn't work for quite some time.

NE555 33K seems to work with 3V3 just fine but I dont have any other module to compare it to tho

Learned this the hard way working on a science competition in high school. Burned through over a dozen and never knew why

I have one with a NE555 21k. The data sheet says that the minimum supply is 4.5v, but it works the same on 5v and 3.3v pins.

i also got the faulty capacitive moisture sensor. chines products are not reliable. did we have any other option to buy best product.

Received 2 "Capa"i"tive Soil Moisture Sensor v1.2" sic. with a NE555 33k wich works with 5v and 3.3

Can't believe it. I failed my final high school biology project because of these sensors.

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.

Thank you thank you thank you. 🎉

Thanks for the overview 👍

thanks to your video I knew how to react to my bad order: Hello, I received your package but the wrong article was inside. It has a NE555 timer chip onboard that does not fulfill the specification of your article description (Operating Voltage: DC 3.3-5.5V). It does not work. Please send the correct items or refund. Best Regards, xx

I have nearly all 3 of the problems, except for me the via is offset, but there is tiny trace to the ground :) Still going to use it, just circumvent the problems by using regulated 5V source ;)

Mate - the point with the missing voltage regulator is just not true. The way these regulators should work, is that you use the actual supply voltage in your algorythm anyhow - and in case of using a battery, you should be monitoring the supply voltage on the mcu anyhow using an analog pin...

Anybody have a link to AliExpress with good sensors?

I'm interested is this still a viable project?

Apparently I need to order a lottery ticket, first one for cheapest price was perfect

Thank you!

Just wanted to report that they're still garbage. 5/5 of Songhe's sensor didn't work even after bridging the missing connection.

Thank you for your video. I recently purchased this moisture sensor as well and encountered the same issue of the missing resistor connection mentioned in your video. However, I decided to test it using an oscilloscope and was surprised to find that it did not exhibit the slow response symptoms shown in the video you referenced (QGCrtXf8YSs). On the contrary, it appeared to respond quickly. I recorded a video to demonstrate this(kzfaq.info/get/bejne/pLSAd7x4mrqxcas.html). Furthermore, I followed your method of fixing the broken 1M resistor connection. Upon retesting, I found that the results were consistent with the previous ones, showing a same rapid response to changes in soil moisture levels.

I bought a V2.0. Sadly while working in short circuted my circuit and I could not finish it. I think all the components are damaged. In your video I found out the the wire hole was now in between on mine. Where can I find good ones?

You speak about the R1 1M in the schematic, but show and measure R4. What did I not get?

Danke Danke Danke

Did u build an "ideal" capacitive sensor? Can you share any designs?

Hi, I know it's an old project, Can you make a complete list and with links (maybe Aliexpress links) to the things I need to buy to make such a plant pot? or perhaps you go with the idea of ​​making a newer and easier plant pot project? 😁

how often do I need to recharge the battery?

how often do I need to recharge the battery?

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?

Geez ... that's so clever ... your project is what l’m looking for. I got a family member who got severe allergic reaction to any conservation product and he bought a garden tour for his vegetables. There's no monitoring at all and I wanted to make him a project so he could see with his phone what he needs to do like puttings fertilizer, reducing the ph etc ... I've try a little project of my own to make a pir sensor so it would send me an alarm if there's any movement. That motion detection is to monitor a mouse trap that I got in my basement where there's no entrance from my house and i've forgot many times to watch it. I got so many issue for build the PIR code ... I mean I wasn't able to send to myself an email while there's movement without buying an online service. I wanted to make my product the most cost efficient and I didn't wanted to spend for monthly free to be able to use something i've build by myself. I ask how to solved my issue in arduino's discord but nobody wanted to help me, so I had no choice to use AI but never been able to make it worked. I'm not a professional programmer and I don't wanna learned a new programming language for my leisure. I'm more interesting by assembling stuffed then coding. I've found a service where I can use there platform for free for 1 or 2 devices but it would only send me an email each 15 minute or so. That's work for me but maybe they would cancel there free trail and i'm will no longer be able to use that motion detector. Your code for talking to an app is what i'm looking for and I hope that I will be able to modify it to my needs and makes my project works. thanks for sharing with us that genius idea and kept that project open source

It seems, that if you order the boards with the round cutouts, they do not have the third issue, but those with angular cutouts do have the issue. This criterium is much easier to see on the picture.

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!

I rarely give a 'thumbs up' for videos, but this one deserves it for being plenty of details. That is great for DIY people, like me. I found the exposition about the capacitive sensors particularly interesting (that's in another video that I suggest you to take a look).

Regarding the missing Ground connection: even if the copper coating on top is intterrupted, not all sensors are faulty. I bought some where this is the case, but the sensor has its ground connection. In contrast to the sensors in the video mine have got two top-to-bottom connections left and right from the white connector. Not sure where the ground connection comes from, but I think the connection is under the white connector.

A resistive sensor doesn't need to be made of copper. Can be made from carbon rods. Works great

Dude this is amazing. This is exactly what i was seeking to build feature wise but I have a different design in mind. Thanks for sharing this and I look forward to seeing other projects you do. I wish we can work together in the future.

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.

Great video! You gave a thorough explanation and demonstration of the problems without wasting time on irrelevant discussions. I also appreciate that you gave some tips for telling if the product is properly made and how to possibly fix it if not. As someone who has resold items online for a few years, I suspect that the sellers are often not aware of the problem, since they are likely ordering from multiple wholesalers. I have ordered from different wholesalers over time depending on their pricing, the quality and availability of their products, and whether or not they still exist! Even though the product images look the same (often they are just copies of the same stock photo), the quality of the products I receive can vary drastically. For the things I sell, it's easy to tell how well they are made and I make a point of clearly labelling and discounting any that are of poor quality. For small deviations like what you showed here, I wouldn't expect most resellers would notice the differences, and some may simply not care or would choose to sell them knowingly because they don't want to take a loss. If you find a particular item you are interested in but you aren't sure of the quality and don't trust the product image, contact the seller and ask them to take a picture of one in their inventory. If they don't respond and refuse to take a picture, move on. I've had people ask many times before and I'm happy to do it if it means they will buy some. It's also why I typically take new pictures of every shipment I receive, so that I can easily provide up-to-date photos without having to take pictures for each request, and I can use them as evidence to get refunds if the product I receive is significantly different than what was advertised. If a seller isn't willing to take the time to do this, then they will lose sales to someone else who will.

Mine had no problem

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!

A good idea to further save battery, is to have MOSFET controlled by the MCU to turn off the voltage to the sensor. Otherwise it will draw some power even when not used.

2 years later, got mine. checked it just now. 1) voltage regulator is there, 662K as it should be. 2) Timer chip: NE555 but 33K label - works perfectly with 3.3V from an ESP32 output. 3) Resistor to ground: checked it, it's working as it should. Interestingly enough, I was certain I had a faulty one, as the printed label on mine said "Capaitive Soil Moisture sensor v1.2"

I have the one with Via located to the side of midpoint between 1M resistor and capacitor. But both sides of 1M resistor is connected to where they should (gnd and aout pins of connector)

Nobody should ever supply anything without a voltage regulator. Most µC-Boards have one built in and provide the output on a pin. This is why.

Ehrenmann

Wondering if you’ve had experience with Pino Tech SoilWatch 10?

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

I also have the 2.0 HW-390 and on mine the resistor IS connected...

I was able to find another defect that's really appalling - TL555I flipped 180 degrees. My sensors always put out 0.7V no matter what I did. Well this was the reason: cdn.zappy.app/b303d668b8dbd7ec81f1151963b644b5.jpeg

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?

Thank you for the video. In my order there was the hole at the wrong place. The 1M aditional resistor does not fix the problem. Any idea? Does anyone can share a link to a good store? Thanks

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