There’s a school of thought that says you shouldn’t mess around with a solution that’s already working, but that’s never seemed to stop anyone in this community. When [Skye] was looking at the current state of connected pH meters they realized there was incredible room for improvement.
Called the Nectar Monitor, this pH meter is a more modern take on what is currently offered in this space. Open source and based on the ESP32, it’s accessible to most people with a soldering iron, fits into a standard project box, and includes other modern features like USB and WiFi connectivity. It can even measure conductivity and temperature. But the main improvement here is that unlike other monitors that can only be submerged temporarily, this one is designed to be under water for long time periods thanks to a specially designed probe and electrical isolation.
This design makes it an appealing choice for people with aquariums, hydroponic farms, or any other situation where constant monitoring of pH is extremely important to maintaining a balanced system. We’ve seen some unique takes on hydroponics before especially, including this build that moves the plants instead of the nutrient solution and this fully automated indoor garden.
Uhm, i think there’s have quite a bit of a misunderstanding… pH/EC probes are ALWAYS submerged, because otherwise they can’t measure anything, and the electrical isolation has nothing to do with being submerged/waterproof, but to prevent interference between the two probes – because they both measure current, at the same time, in the same liquid. It doesn’t say anywhere that the box itself can be submerged, which would also be pretty pointless.
So in short: just another pH/EC monitoring project, just with a custom PCB.
How about you show off your projects (if you even have any) instead of criticizing others who actaully did something good.
okay… that’s a pretty harsh response. Did you do really do any research about J. Grewes projects before you typed “show off your projects”?
However, I have to agree with the comment of J. Grewe as I’m wondering the same thing, what is it that makes this design so special as I can’t seem to find any info (on this Hackaday page or in the provided link) about WHY this design is actually an improvement, what technical challenge was solved and more importantly HOW? Just mentioning something is specially insulated or protected against water doesn’t cut it for many of us here. We like details so that we all can actually learn something from it.
I don’t see it as criticizing the project, but the text.
I personally think it’s a great project for those that have the need for it. When I need to measure pH I do it using sensors my employer buys and you end up with the nke wimo plus or something else very expensive but very precise. But I’m measuring pH levels in the oceans, rivers and lakes all around the world, not in an aquarium. This might (text doesn’t really specify why) be a great solution for home use.
I don’t see it as criticizing the project, but the text.
I personally think it’s a great project for those that have the need for it. When I need to measure pH I do it using sensors my employer buys and you end up with the nke wimo plus or something else very expensive but very precise. But I’m measuring pH levels in the oceans, rivers and lakes all around the world, not in an aquarium. This might (text doesn’t really specify why) be a great solution for home use.
Wow! Harsh response to valid criticism of the writeup.
For continuous monitoring of Ph/EC the probes need both electrical isolation and to be continuously submerged. That’s not really a feature so much as a basic requirement.
I was excited by the writeup cause it read like they’d developed a way to make continuous Ph/EC probes at home. Then I read the project itself and saw that it just uses COTS probes.
The project itself seems to be nothing more than a pointer to a crowdsupply campaign. There’s nothing there but a few pictures and advertising text.
Home-made pH probe: https://www.youtube.com/watch?v=rkgUStPq6g4
Woohoo! Thank you!
Christ, I’ll just buy one or stick to swimming pool regents. This video is a great example of patience vs practicality, but it serves as a piece that should be in a human kind vault for when s#!t hits the fan there’s something to follow along and maybe teach.
That’s a good example of hacks that should overwhelmingly prevail on Hackaday.
Very nice video, with all underlying chemistry and math.
Thank you.
PS: AFAIR bismuth could be used instead of antimony in such electrodes too. Bi₂O₃ behave similary to Sb₂O₃ regarding electrons and all that stuff. Bismuth is less toxic than antimony, so it could be preferrable in some applications.
There are commercial pH sensors with BT/WiFi for homeowner’s pools. My understanding is that they don’t work very well over time because the probe needs periodic calibration. This is done by using fluids with known pH. Most homeowners don’t want that “hassle”. How does this compare ?
You could probably get by with weekly or less calibration, it’s a swimming pool not a finely tuned commercial operation. I’m sure it could be automated too with a 6-way valve and peristaltic pump. Run a single point calibration once a week and a full 3 point calibration when you open & close the pool for the season.
There’s also industrial FET based pH sensors that don’t need calibration (in theory) but they are subject to fouling & are probably only good for a season.
There is nothing nowhere in provided links about that.
There is a great problem with pH sensors (at least traditional ones – with glass or plastic electrode filled with KCl solution) – they are wear out quickly being constantly submerged and require periodic recalibration with buffer solutions, and service to restore proper KCl solution in glass electrode, so have to be unmounted from installation, which is sometimes not only annoying, but also problematic, especially if measured media is under pressure or hot.
Hydroponics enthusiasts even create complex systems to allow somehow unattendent continous pH measurement, like kind of robot that take pH sensor out of measured media, sequentially put in distilled water and buffer solutions for calibration and if it is out of KCl place electrode into saturated KCl solution for some time to restore it, then do calibration again and eventually return sensor into measured media. I also saw project with kind of chamber for pH probe and array of pumps to do procedures without probe movements. Very interesting and complex projects, really, but not KISS ones.
And even with all the care and only periodic lab use, pH probes last only few years at most. Constantly submerged one, even with that complex automatic calibration and service hardly will last more than a year, and will need at least complete overhaul (cleaning glass bulb and refilling with fresh 3M KCl with few days waiting to allow ions saturate glass membrane) if it serviceable at all.
There is note that device
But off-the-shelf probe can’t work 24/7. They lose KCl in glass electrode being constantly submerged and will measure weather on Mars.
IDK, but looks like it is not very honest attempt to attract people who look for real 24/7 pH sensor that does not require complex mechanical or hydraulic system to work properly without human interaction.
I initially get impression that project authors developed some new kind of stable and long-lasting pH probe that does not have drawbacks of glass bulb electrode ones, but was disappointed when took a look into.
Mac is correct. pH probes gradually deteriorate as soon as they are manufactured. Over time the solutions they are in begin to leech into the “glass bulb” or whatever other construction the pH probe is. They need to be re-calibrated at specific intervals using known pH buffers (usually two points, 4 and 10). Not only are the endpoints (and slope) important, but the reaction time it takes to go from zero to span. Some pH probes might be accurate at a particular pH, but the probe is so dirty it takes minutes to get the correct reading.
I worked on pH sensing for a small scale commercial hydroponics company a few years ago. All I can say is, unless the probes are actually made by a big-name company (made for “industrial” purpose), the datasheets aren’t worth the paper they are printed on.
Most probes that we got from China copied the same datasheet from somewhere with the same exact graph and other info. That would’ve been acceptable, we could have just characterised the probes to get some good data. Nope! The probes, even from the same manufacturing batch had massive differences and irregularities. I have no idea if it was some chemistry thing or their manufacturing process and tolerances were loose (to say the least).
The probes themselves are quite complicated in their construction with glass membranes and gel layer to diffuse H+ ions, but electrically they are quite simple. They generate an electrical potential between two electrodes (can be as high as a few 100mV) for the change in the H+ ion concentration (aka pH) of the test solution.
Anyway in the end we decided that dealing with all this mess just wasn’t worth the effort. The probes all sorta worked, but every piece behaved differently so we put a guy at the end of the assembly line with a bunch of buckets with known pH solutions and added a routine to the firmware to make a PWL table. It was a massive bottleneck in the assembly process but it was simple enough and worked magnificently.
The probes however drift away if they are left in water for too long. We gave customer the calibration liquid but they really didn’t care if their readings were incorrect.
In the Industrial Electronics world (like a water treatment facility), pH is the hardest thing to measure accurately and requires a lot of pH probe maintenance. In many cases, we keep a clean and calibrated set of pH probes on hand and swap them out each day. We clean the dirty ones, check calibration and set them aside for the next day.
I don’t see any project files (not on github or hackaday), schematic firmware ect. Only a bit of text and some photo’s. It does seem to implement the PH ECsensorrs discretely. Is it using a off the shelf fully integrated IC like the LMP91200 or is the circuit implemented using op-amps.