Newbie question command sensors

Hi guys,

I’m new to Arduino and I have a quick question, maybe silly.

Currently, I use an Adafruit temperature sensor (link below) to gather temp data. It works well and it is user friendly to command it due to the libraries as OneWire and Dallas temperature, and the Adafruit tutorial.

For the development of my process, I need other sensors more industrial.
But in those cases, I don’t know if I can use those sensors with an Arduino.

I only have the command specification (PT100 or 4…20 mA).
if I was working with a PLC, I could have configured the minimum and maximum value of the signal easily, but here again, I don’t know if it is possible with Arduino.

So my question is :
If I found a sensor with 3 wires, one for the -, one for the + and the other one for the signal (So as I said, PT100 or 4…20mA), can I read the data on the Arduino without a specific library (specific at the manufacturer)?

Thanks for your time,


Adafruit temp sensor: Waterproof 1-Wire DS18B20 Compatible Digital temperature sensor : ID 381 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits

may you could take a look here.

You can use PT100 and other sensors that are designed with industrial use in mind.

arduino pt100

arduino 4-20mA loop

They will show you what is available and how to use them.
In particular there are modules/shields for PT100 temperature sensors.

Tom… :grinning: :+1: :coffee: :australia:


@paulpaulson I don’t understand if the code works with all types of sensors. But in my case I will work with immersive captor.

@TomGeorge thanks !!! It’s really what I wanted to know.
But I have a question …
In the same Arduino (mega 2560), I will gather PT100 sensors, 4…20 Sensors and motors shield to control peristaltics pump or electrical valves.

Thanks to your answer, I found this board (4-20 mA (Current Loop) Sensor Board for Arduino, Raspberry Pi and Galileo) for the 4…20 control, this one (Module amplificateur pour PT100 ADA3328 Adafruit - Amplificateurs | GO TRONIC) for the PT100 and probably I will use shields motors in addition (As TB6560 / TB6600 / Pololu A4988 …).

I can stack the 4…20amp shield on the Arduino but can I stack the motor shields and PT100 shield on the 4…20amp shield? (For the supply, I will put a 24V supply on the shield motor and a 5V supply for the Arduino and the others shields).

I think I need to look deeper into what pins each shield uses :thinking:

What is your project?
What are you going to input and output?

Can you please tell us your electronics, programming, arduino, hardware experience?

Tom… :grinning: :+1: :coffee: :australia:

Hi @TomGeorge ,

I will try to make it short :

I work for a biotechnical environmental company.

For our project, I have one vessel where I put some inputs/outputs:

Inputs are sensors like Pressure (4…20mA), flowrate (4…20mA), and temperature (PT100 for the moment because the same with 4…20mA is very expensive).

In Outlet, I will use some peristaltic pump 24V DC and a lot of valves 24 V DC (one proportional and the others ON/OFF).

I don’t have a large experience in this field because I’m only a Junior engineer.
For the moment, the biggest project that I have created is to have one Arduino 2560 to control one peristaltic pump, one proportional valve, one temperature sensor, one weight sensor, one lux sensor. And all the data was monitored by Thingspeak cloud (or Adafruit IO).
But in this project, my sensors were easy to use because compatible with Arduino.

This will not be the case for my next work, which will be the V2, with more than 10 sensors, more than 10 valves, maybe 3 or 4 pumps … And I need more industrial sensors due to the conditions of our future experiment.

In addition to this project, for another experiment, I control an Uno with a Raspberry Bi and push, in a cloud, 8 data of lux sensors by using I2C communication and a multiplexor. I also heard about shift registers …

Finally, I will use a Raspberry Pi to control my Arduino, for better communication and test programmation (C++ and Python code). I will use a mega 2560, of course. If possible, I would enjoy reading data of my sensors by I2C but I don’t know if it is possible with the 4…20mA signal.

I hope it’s clear.

Alex… :clipperton_island: (Sorry if the syntax of my sentences is not always good)


Your syntax is fine mate.
Nice paragraphs explaining each aspect.
Will you have enough I/O for all your sensors with the 2560?
Are you using some port extenders?

Good to hear you have a similar project up and running.

Thanks… Tom… :grinning: :+1: :coffee: :australia:


I don’t know because we didn’t finalize the equipment list yet … But I can use shift registers or I2C multiplexor I think. In another part of the forum, somebody advised me against the use of the GPIO extension without these two possibilities.

What’s your project?

So I’m not an expert in Arduino (and especially with industrial sensors and pumps) and now with the V2, the number of sensors/pump/valves explodes and I don’t know if I can carry all the shields (motor/4…20/pt100) in only one mega 2560 (without the supply voltage/current question).


Do you need to change the direction of your motors and/or change speed?

There are various port expanders, I2C and SPI so depends on your needs and pin availability.

I2C will keep your pin count down to 2 signal and two supply connections.

Have you a block diagram of your project, laying out all your sensors and outputs. That would be a good start.

Tom… :grinning: :+1: :coffee: :australia:

No, I have one principal vessel. Pumps route some liquid from a substrat tank to my vessel. For this, I need peristaltic pump because my flow rate is extremy low (1ml/min), and for the moment I’m looking forward stepper motor or brushless which can be ON 24h a day 7d/7.

For the moment, I only have the command type (4…20mA for exemple) of the sensors / valves that I found. I don’t know If I can read data via I2C or SPI. Is it the shield who enable to use those communication ?

I have PID diagram yeah but I can’t share it :laughing: obviously


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