What is the correct hardware required to connect multiple analog sensors to a Raspberry Pi 4?
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?
I saw this one here, DHT11, which seems simple. https://www.robotshop.com/ca/en/dht11-temperature-humidity-sensor-module.html?gclid=EAIaIQobChMI5raHo4Tf6AIVUPDACh2czgVYEAQYBCABEgIkHPD_BwE
I found this sensor kit, https://www.atlas-scientific.com/product_pages/kits/ph-kit.html
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!
This question is too general. You could search for A-D modules, but frankly if I wanted to do this I would use an Arduino. There is minimal processing involved, so the Pi-4 is overkill – a PiB+ would be adequate. You will also find more instructions for Arduino. – Milliways 3 hours ago
Totally get that Arduino is the better platform, but I want to stand a Swoole server to serve as dashboard. That’ll be easier on the Pi 👍🏻 – Saeven 2 hours ago
1For pH, the following might help: raspberrypi.stackexchange.com/questions/96653/…. – tlfong01 1 hour ago
1For temperature, this might be useful: raspberrypi.stackexchange.com/questions/100203/… – tlfong01 1 hour ago
1For moisture, this reference should be a good starting point: raspberrypi.org/forums/… – tlfong01 1 hour ago
1For pump: raspberrypi.org/forums/… – tlfong01 1 hour ago
1For controlling a pump, you probably need a relay: raspberrypi.org/forums/viewtopic.php?f=37&t=77158#p1323061 – tlfong01 1 hour ago
1For controlling solenoid valve: raspberrypi.org/forums/… – tlfong01 1 hour ago
1For ADC of multiple sensors, you might try multi-channel ADS1115; for multiple actuators, you might need MCP23017. Of course there are many other choices, depending on your application and objectve. Eg, if your objective is to learn and start small, you might like to try 8 bit or 10 bit, ADC3008, which a much easier than 16 bit ADS1115, of course there are 24 bit ADC such as ADS1250 for you to show off – tlfong01 1 hour ago
1For humidity, I would recommend DHT22, instead of DHT11: (1) “RPI ZW Multiple Sensors – 2019feb11”: raspberrypi.org/forums/… (2) “Searched query: dht22 tlfong01: Search found 53 matches: dht22 tlfong01”: raspberrypi.org/forums/search.php?keywords=dht22+tlfong01 – tlfong01 57 mins ago
For weighing your finky little plants, I would recommend load cell with 24 bit HX711 ADC.raspberrypi.org/forums/… – tlfong01 46 mins ago
PHP Swoole server seems a bit overkill. For RDBMS newbies like me, I would prefer Rpi friendly MySqlServer and newbie friendly GUI PHPmyAdmin. References: (1) Setup a Raspberry Pi MYSQL Database – Emmet, PiMyLifeUp 2019jul04 pimylifeup.com/raspberry-pi-mysql, (2) How to Install PHPMyAdmin on the Raspberry Pi – Emmet 2019jul04 pimylifeup.com/raspberry-pi-phpmyadmin. Cheers. – tlfong01 31 mins ago
1Thanks for all the links, really appreciate it. I’m an extremely strong programmer, just an absolute zero when it comes to cobbling circuits and electronics from scratch like this. If I can get the sensor readings into PHP, the rest will be a breeze! – Saeven 28 mins ago
Ah, for electronics newbies, I always recommend to start off with AdaFurit and SparkFun’s newbie friendly tutorials. ADC usually give you conversion results in binary or decimal numbers to input to mySQL which can be connected to a PHP talking guy, and so Day is done: youtube.com/watch?v=5UrunpqtcIE. Cheers. – tlfong01 17 mins ago