Is it possible to have multiple conductivity measures on one arduino or would I have to have them all separate from each other

I was wondering if there was a way to have multiple electrical conductivity measurers on one arduino. Or if I wanted to have multiple of them at once then would I have to have separate arduino's for each one? This is for the case if I'm wanting to have lets say 2+ conductivity measurers measuring the conductivity inside a solution I have. I can't really go into the details of why but I was wondering if there was a way for this or if there was a better way around this instead. Thank you!

In this question, there’s an assumption you already have an electrical interface to acquire the measurements you’re looking for.

That being so, the Arduino is certainly able to monitor, log and store multiple input data sources- limited by sampling rate, sample complexity and available storage for the logged data.

I personally don’t see any problem with the problem as it stand so far.

With more information, we can probably offer more answers.

The lowly Arduino Pro Mini had 6 analog input channels. As @lastchancename mentioned each can be monitored. But only one at a time. This is normally not an issue and a measurement only takes some number milliseconds. The actual time depends on how you setup the input.

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Specify the to be measured electrical conductivity in detail.

If each measurement is independent of the others you can certainly make multiple measurements with one "arduino"
(it would help if you gave a link to the device(s) you are using)
It would also help if you linked to the sensor you propose to use.

Conductivity is a tricky thing to measure

I'll try to my best to ask it in better detail but I am unfortunately not the best with this kind of stuff. So to be specific and adding onto it. I am currently trying to find the most efficient way to have multiple electrical conductivity measurers reading the conductivity values at the same time. For example, I would want to have maybe around 4 to 5 probes in an area for some specific reasons to measure the conductivity in order to monitor the conductivity as i'd pour salt water in from one direction as it flows to the other direction. Ideally, it would be nice to have tall the ec measurers on one Arduino A000057 or the Arduino nano or if there was a specific sketch I would have to use to make this work. Either that or if I would need to have multiple different Arduino nano's or something else to read the conductivity in the water as I pour in the salt water. (Also on a side note, would the ec measurers affect each other if they are somewhat close contact with each other.) I am not vey skilled with any electrical engineering rather more of teaching myself this slowly and learning about it as well. So ideally, multiple ec measurers reading values at the same time is what I am looking for and to see if it is possible as well. Hopefully, that clears up and provides a bit more information! What I'd be measuring would be the salt in water whether it was ground water or salt I would put in water.

I would use either the Arduino the classic one? Unless there's a name more for it or Arduino nanos. KEYESTUDIO TDS Meter Probe Water Quality Monitoring V1 Sensor Module with XH2.54-3Pin Jumper Wire Connector for Arduino is the sensor I am using for measuring the electrical conductivity. My plan is to break apart the 2 probes and bring them close so I can try to get a higher K value for the smaller readings I would get from lower concentrated salt concentrate in possibly ground water or other waters. I am just not sure what the sketch would be exactly if I had it on 1 Arduino nor understand if this would be efficient or if it can cause problems to arise for when I retrieve the data or so. Or if its better to have multiple arduino nanos setup and to have them individual setup instead and to take those values instead!

In all your designs, keep in mind that conductivity is the reciprocal of resistance. All of your measurements are based on the resistance changes. Your math must convert that to conductivity.

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It would benefit you to know more about Arduino and make progress in steps that you debug and use before each next step, like finding out if you can make one work before 4 or 5 at once.

1 - The Arduino chips have IO (input/output capable) pins, some capable of reading analog Voltages.

2 - Your circuits connect to the IO pins. The chip works with those through your program.

2A - Any IO pin set to read (INPUT mode).... when not being read looks like electrically neutral to your circuit. During read the pin takes in 1 microamp as a sample.

2B - IO pin mode can be changed in a single cpu cycle. Same pin that lets me drain a capacitive sensor let's me fill it with weak 5V (through 20K-50K resistance) while I read the pin to see how long it takes to change the pin from low to high then do it again.

3 - Analog read takes much longer than digital read. When you switch analog pins the 1st read on the new pin will be garbage, read twice and use the 2nd read as data.

3A - You might be able to read 4 analog circuits in 1 millisecond.

Whatever you do, do not underestimate how much you may have to learn to do it.

Just for reference, this is the device in question.

As in general, the Nano is the appropriate Arduino to use - particularly as it has eight Analog inputs while the UNO has only six.

The Pro Mini also has of course, eight analog channels.

The Arduino community PJRC made the Teensy 2.0 with 12 analog pins and 2560 RAM.
Pins optional.

Teensy 2.0, Arduino Micro came later.
See if Arduino still makes the Micro.

OTOH, if you really need simultaneous reads then use ATtiny chips that cost half or less as much as ATmegas to do the reads, each reading 1 sensor, all connected to an SPI or I2C bus. You can fit 5 8-pin ATtinys on 1 40-pin narrow form socket, wire it up and read 5 analog sensors at once.

At the moment, I plan on using the ATTINY85 connected to the TDS meter probe. From what I see, it looks look I will have to use the SPI or I2C bus. Are there any good posts in understanding the SPI or I2C bus utilizing it with multiple sensors? Also, I am thinking of utilizing a sd card module to take the inputs of the data from the sensors and record them to there. I am not to sure how this would connect to the SPI or I2C bus I guess is what I am trying to get through. I will do my own research on this as well but any suggestions on this would be great too! Thank you everyone! You guys are awesome!

Maybe all you need, including SPI slave code.

Depending on how much, how fast the data is collected, the bus master "brain chip" may need more RAM. A bigger buffer (512 byte default, 34 byte minimum to get burst transmission) may be desired.

Don't lay out a design before you know the parts.

I would suggest that you make each aspect of the project into a working project itself with debugged code. You don't want to learn details of multiple unknowns while building what you've never seen. So take your time.

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