Any suggestions for temperature controlling and water controlling sensors?

Using Arduino Project Guidance
#1

Hi to all,

It is good to learn from here! Recently I am considering building a system that could 1) control temperature of the environment, 2) water level of a water tank and if possible 3) light intensity control as well for a hydroponic system.

First of all, I just need to build a small prototype. Does anyone have good suggestions of what kinds of MCU boards and sensors I could use, like what part numbers? And do I need to use different boards to achieve those three different functions? Is there an MCU board that could achieve all of them?

Thank you!

#2

@sdoamy

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#3

Pretty much any Arduino compatible board would work. You will not need a lot of pins. A good starter would be an Uno or Nano.

The DS18B20 temperature sensor is what I would use. They come in a waterproof version. They are digital and only need one pin for several sensors.

The simplest water level sensor is a float switch. Very easy to interface. If that will not do there are alternatives.

You can control a pump with the Arduino. The pump motor will need a driver and external power supply.

To give any more detailed help, we need to know more about the project.

#4

groundFungus:
Pretty much any Arduino compatible board would work. You will not need a lot of pins. A good starter would be an Uno or Nano.

The DS18B20 temperature sensor is what I would use. They come in a waterproof version. They are digital and only need one pin for several sensors.

The simplest water level sensor is a float switch. Very easy to interface. If that will not do there are alternatives.

You can control a pump with the Arduino. The pump motor will need a driver and external power supply.

To give any more detailed help, we need to know more about the project.

Thank you! For the current moment, we would just consider building temperature control functions, water level control functions. What I am curious about is that (as I just gained basic knowledge about Arduino) if I could integrate both these functions together in the same board?

#5

This type of tethered float "ball" switches are very reliable, but they are designed to switch mains voltage to a 200 to 500 Watt pump motor and are therefore large (> 8 cm diameter) and costly, looks like someone would make them in a thumb sized model that could switch 500mA low voltage for a relay or MCU input. But...

#6

Yes, almost certainly. But to be sure you must supply a detailed description of what you want. Do you need heating? Cooling? How much water? How fast to heat or cool the water? And give us numbers, not ambiguous figures like "a lot" or "fast". Same for level control. Is there a pump? Or a valve? Do you just need to put water in or drain it, too. How much water? What is the container? Can a simple level switch be used?

General questions get general answers.

#7

groundFungus:
The DS18B20 temperature sensor is what I would use. They come in a waterproof version.

Do they indeed? You mean the one with the stainless steel (presumably) tube?

I seem to recall reports that they may be rainproof, but not suitable for immersion.

Float sensors:

#8

if you do not require high accuracy horizontal or vertical float switches work well and will interface to a microcontroller GPIO pin

#9

Those tiny magnetic types are prone to slime / algae build up if used outdoors in less-than-clean water, been there. :slight_smile:

#10

the better you define your 'environment' the better.

assuming a simple hydroponic garden in a warehouse, you have a significant stability of environmental conditions.
in a tunnel greenhouse, less control, but by your choice. double or triple wall, geothermal heating/cooling, etc

But, you assume a simple IBC tank of 250 gallons (1,000 liters) for your main storage tank
and 4 others cut in half for 4 growing beds.
A swimming pool pump for circulation
A few peristaltic pumps for adding various nutrients ????

You can put in your growing tanks with a skimmer on top, like a swimming pool. That is your level control for the growing beds

You circulate water so you have control of the temperature at many points, but only need to know one for the storage tank and all the rest will be close.

light sensors, no problem.

a trio of water level switches. high : stop filling, low : start filling, and medium for S&G, you need 3 inputs.

[ S&G is a technical term often used in engineering for adding extra things that would be helpful, not not absolutely required. Slang of S&G = American for laughing so hard it comes out the other end, spoken as s#!ts and Giggles. I do not know the translation into British English]

light level in each of 4 tanks, = 4 inputs

lights off and on, 4 outputs

so,
water temperature for control = 1
water heater for control = 1
tank water level = 3
fill pump/valve = 1
temperature = 1 per tank = 4
light sensor = 4
light controller = 4

figure 18 inputs and outputs to get started. easily done by any of the available micro-controllers we discuss on this forum.
even an ESP8266 with some expansion cards.

What you didn't ask was to put that information on your local web/network/datalog
You will need to use either a wired in network card or some WiFi device.
Also simple and common. The new NANO-33 IoT boards or an ESP32, or the ESP8266 with some expansion cards.

It is always helpful, nay, REQUIRED to Define the project before selection of parts. The answer to your 30,000 foot overview question is YES, the Arduino is a good platform and YES, there are a variety of low cost sensors that can be obtained and YES, this forum can help you each step along the way. and YES, there have lots of people that have done this before.

The answer to your focused, part number question is based on your detailing the thing you need to do.

#11

Paul__B:
Do they indeed? You mean the one with the stainless steel (presumably) tube?

I seem to recall reports that they may be rainproof, but not suitable for immersion.

The DS18B20 sensor is a TO92 case.

Put that into some epoxy in a stainless tube, add some heat shrink and your waterproof is dependent on your use.

Immersed at water lever is one thing
Down 10 meters is quite another.

You can get long tubes and make your own.
Use the gland connection for waterproof cases and have that seal on the stainless case
For water tank monitoring, you can attach to the outside of the tank and insulate it.
You can put it into a pipe and submerge the pipe. the pipe will stabilize with tank temperature.

you can take a PVC pipe fitting drill a hole, insert and seal, our use a Tee fitting.....
Your premise that you cannot rely on every $1 part to meet the most basic quality control is so valid, it should be in bold letters.

Once you get into industrial control, there is a housing, there is a part a Thermowell. A hollow tube that seals in the tank. You can pull the temperature sensor out for test, calibration, etc without draining the tank. the sensor is non-contact with the inside of the tank.

I just found out that the Arduino clone chips, are just that clone chips. not Atmel chips. sigh........

#12

cable gland CABLE GLAND

DS18B20 in sealed thermowell with cable gland.
not sure if the sensor is removable.
from aliexpress : thermowell

800×800 89.4 KB

1000×1000 38 KB

#13