What is the correct hardware required to connect multiple analog sensors to a Raspberry Pi 4?

Question

I've been an avid Bonsai enthusiast for some time, and have always wanted to automate some of the day to day tasks (and get some data logging in the process).

I'd like to be able to detect:

• soil moisture in 4 containers
• room humidity and temperature
• pH in one of the containers (more finicky plant)
• control 4 individual pumps

I've found several tutorials that deal with "connecting one hygrometer", but where I don't truly understand how the pins on the RPi work, I'm looking for some insight on how to scale this out.

Next part, I realize that the Arduino is has analog capabilities the Pi doesn't, but the familiarity with the programming languages available on the Pi are driving the decision.

Soil Moisture Detection

I've found these sensors, https://www.amazon.ca/Gikfun-Capacitive-Corrosion-Resistant-Detection/dp/B07H3P1NRM, which I understand need an ADC so that I can get percentage values out of the units.

I've also found this ADC, https://www.amazon.ca/Adafruit-PID-1085-ADS1115-16-Bit/dp/B00QIW4MGW/ref=sr_1_6?keywords=ADS1115&qid=1586561797&sr=8-6. Not sure how they get wired up, but it says 4-ch, which I imagine refers to its ability to handle 4 sensors?

Temp/Humidity

I saw this one here, DHT11, which seems simple. https://www.robotshop.com/ca/en/dht11-temperature-humidity-sensor-module.html?gclid=EAIaIQobChMI5raHo4Tf6AIVUPDACh2czgVYEAQYBCABEgIkHPD_BwE

pH Detection

I found this sensor kit, https://www.atlas-scientific.com/product_pages/kits/ph-kit.html

Water Delivery

This pump looks right! https://www.adafruit.com/product/1150

Is this enough?

Now, where I'm a great coder, I'm not an accomplished circuit board connoisseur! How to get all these pieces 'wired' to the Pi?

Thanks for any insight!

Answer 1

For the soil sensors I would look to this ADC board as it will handle four sensors at once.

DHT11 are not my goto sensors - they can drift and are not great in the accuracy steaks either. For outdoor / wet areas I would use a DS18B20 such as these inc resistor

The humidity sensor I have is the BME -680 board but I've not deployed this live yet and would be going indoors.

Note on the Arduino style boards you can run either Micropython (e.g. UnexpectedMarkers great WiFi enabled TinoPico) or Circuit Python - it does not have to be the normal IDE and C/C++ :)

Happy to edit this with more notes - just drop a comment below with more needs...