Arduino PH Sensor for permanent outdoor monitoring.

G'day everyone, I have been looking around the web regarding the following project but I don't seem to be getting anywhere.

My boss wants some information on a project he wants to go for. A client wants to automate the PH measuring of their water dam that is near a rock quarry. The water gets acidic at times and they want automatic notifications if the PH gets too high so they can neutralize it.

We need a permanently immersed PH sensor that can be programmed to take samples every so often, and then send an SMS message with a reading of the water and a warning if the PH exceeds a certain range.

There is small shed near the dam we can store the arduino in as well as a battery. The entire circuit needs to be run off DC since it will be solar powered.

I've found some PH sensors, but most seem to be for testing but not permanent immersion.
Here is an industrial one that looks promising but it needs regular maintenance from skimming the specs so it might not be suitable.

https://www.dfrobot.com/wiki/index.php/Industrial_pH_electrode(SKU:FIT0348)#Introduction

I've found a GSM Module here ->

Accessories — Arduino Official Store that appears suitable.

As for my skills, I have not done electronics for a few years and have not had the opportunity to use arduino yet. I am employed as young programmer at the current time so the code side of things shouldn't be difficult as there appears to be plenty of documentation on the web.

Thank you for your help and advice!

TLDR:

Need to permanently immerse PH sensor in dam water to measure PH and send SMS to client if PH exceeds limits. Circuit will be solarpowered and in a shed, sensor will be exposed for now. I am a programmer and have not used arduino before.

Tenniss:
My boss wants some information on a project he wants to go for. A client wants to automate the PH measuring of their water dam that is near a rock quarry. The water gets acidic at times and they want automatic notifications if the PH gets too high so they can neutralize it.

Wait, pH get's high (basic) or low (acidic). How low does it go? That's going to affect the choice of probe. What else is in the water? Is it really hard? Salty? Super-pure (in which case you may be hosed)?

You're not going to get a pH probe that will be a permanent installation with absolutely no need for maintenance. They'll all need to be recalibrated and cleaned periodically. To get the least amount of maintenance needed go for double glass junction probes, non-refillable. No wicks and no holes in the probe. This way it will last the longest under constant monitoring, but will also be the most expensive type of probe. Someone will still need to go out and pull the probe and recalibrate the meter once in a while. How often? It depends on lots of things. But if you have some sort of idea what sorts of numbers to expect then you can recalibrate when the numbers seem off. The other big issue is bacterial / algal growth. Stuff is going to grow on the tip of the probe. You can't really stop it. Having a double junction will help since the inner junction stays clean, but you still occasionally have to go clean it and recalibrate. The coarser you can stand on the measurement the longer you can get in between probably. If you can stand it being off by a whole pH unit then you can maybe let it go for days or even weeks depending on what else is in that water.

Thank you for your reply, and I apologize for my late reply.

Essentially what I've been told is the water starts to get too acidic so whatever lower ph bounds they want to capture, we will have to check for that.

The dam water is freshwater, which can be dirty, but again the exact details are unknown to me.

Any recommendations on a board as well? :slight_smile:

I've seen people use something like this to connect a pH probe to an Arduino.