Smart Garden System

[despinoza]

Hi all!

I am trying to implement sensors to a community garden so that it may measure temperature, humidity, light, rain, and soil moisture. The garden is approximately 3.4 m * 4.6 m and would prefer to use one micro controller to receive the analog data but am aware that the longer the wires are the more the probability that resistance may tamper with the accuracy of the data. Is there a way to connect the sensors to the micro controller a minimum distance of 5 feet part so that the voltage can flow accurately?

 

[MintJulep]

Seems like everything except the soil moisture sensors could be very close to your micro.

For the soil moisture sensors, pick one that supports I2C. That will easily get you 10 meters, probably more with twisted pair.

 

[despinoza]

Would an 8-bit micro controller be appropriate for this project? I plan on having multiple sensors be pinned to it. I also am going to keep it in a box that covers it from the elements.

 

[IRstuff]

Would an 8-bit micro controller be appropriate for this project?

Sure, I would suggest that you pick something with lots of support, software, user community, etc.

 

[MintJulep]

Sure. Pick one with enough analog inputs if you're going to use sensors with analog signals.

Define what you need to do first, then pick hardware that supports those needs; not the other way around.

 

[despinoza]

What I want:
-Monitor temperature, humidity, light, rain and soil moisture of a garden.
-Send that data to a Google Sheet and display graphs zoomed out synchronously.
-Use low voltage and low costs.
-Cover a good portion of land, like 3.5 m * 4.6 m

What I need:
-Micro controller.
-Sensors.
-Google Sheet coding skills.
-Power source.
-Wifi connection.

What I am asking:
How can I send Arduino analog data to Google Sheets to make a graph that shows the data and updates it in a graph?
Will I be able to replace my sensors with a jumper wire that is long enough to cover the garden?

 

[MintJulep]

How can I send Arduino analog data to Google Sheets

Google sheets API. If you use microPython there are many libraries that make the integration between Python and the API easy; unfortunately many of them seem a few years old, and might not have caught up with the latest table features that will make the job easier inside Gsheets.

It isn't much more difficult to use a generic API interface library like requests.

make a graph that shows the data and updates it in a graph

In Gsheets, create graphs of ranges (or preferably tables). Add data to the range (or table). No need to use the API to create or update the graphs.

However, you'll need to think about how to show the latest whatever period of data you want to show.

Will I be able to replace my sensors with a jumper wire that is long enough to cover the garden?

???
You're garden isn't very big. Do you think that the temperature, or the humidity, or the sunlight or the rainfall is going to be different from one corner to the other? Those sensors can all be very close to your Arduino.

Soil moisture will vary because plants use water, and gardeners add water in various ways. As I suggested before, use I2C capable sensors so you don't have to worry about voltage drop.

Power source.

If plug power isn't easily available you could probably use battery + solar.

Wifi connection.

Is the garden in range of a Wifi connection?

 

[Eufalconimorph]

I'll note that I2C is designed as an on-PCB bus, it's not meant to run over long cables. It *can*, but excessive bus capacitance has certainly caused me annoying failures in the past. I much prefer differential buses like RS-485, CAN, or Ethernet, but do a test with I2C first because it's MUCH cheaper & easier to set up (no extra transceivers, simpler protocol, etc.).

 

[IRstuff]

Given your particular application, which I suspect does not have anything happening at the micro, or even milli, second scale, you could run your I2C bus at 1 kHz, as suggested here: https://electronics.stackexchange.com/questions/106265/maximum-i2c-bus-length