Hi everyone, my project is to build a greenhouse environment monitor and watering controller.
This will be my second attempt to build such a device. The Mk. 1 never worked too well. If left to its own devices, the plants would end up too dry or the greenhouse flooded! I still don’t really know how I am going to avoid those two extremes with the Mk. 2, so read on, and if you have any suggestions, please let me know.
I will describe how the Mk. 1 worked in more detail in a later post, but to summarise, it consisted of a single home-made soil moisture sensor, a Picaxe 08M2 microcontroller and a 12V boat bilge pump. It was powered by a 12V SLA battery which was kept charged by a solar cell. It was one of my very earliest electronics hobby projects.
The Mk. 2 will add temp & humidity monitoring inside the greenhouse, and possibly multiple soil probes. It will allow remote adjustments of the desired settings (maybe only from within my LAN) and data logging to a MySQL database on a remote server. The logged data can be viewed through a web interface which I have already developed. You can see examples of how that looks on my weather station and indoor sensor links below.
The Mk 2 could go two different ways in terms of technology. I am going to try to progress with two designs and see which one starts to look like the ultimate winner.
Technology Choice #1: Wemos D1 Mini Pro. This is a dev board based on ESP8266 and I would be developing in C/C++ using the Arduino IDE. I am very familiar with this approach and have used it recently in my weather station and the indoor sensors in my home.
Technology choice #2: Pi Zero W, with an Automation pHAT. On a recent shopping trip to Sheffield, I visited Pimeroni HQ and met and talked with their friendly staff including Phil & Paul, who took an interest in my project and convinced me to consider this alternative approach.