This is a personal project to build an Environment Monitor for my Polytunnel where I mostly grow chillies.
The project consists of three parts: the case to hold the monitor, the hardware (PCB and Sensor(s) etc.) and the software.
The case is designed in OpenSCAD and is suitable for printing on a 3D Printer. I am very pleased with the results of the design. Please feel free to use and improve - within the terms of the license of course.
The Schematic and PCB are designed in KiCAD. The board has not yet been fully tested. In fact the board has several flaws, some of which do not seem to be problematic, but one that caused me a long headache. The pin called CH_PD on my board needed to be pulled high. I have tacked a 4.7k resistor to the back of the board. Without this, the board would not start. Oddly though, in all of the previous ESP8266 designs I have worked on (mostly on vero or breadboard) I have not had to pull this pin high at all. Please be warned if you want to use my design.
As of version 1.4 of the schematic and PCB the above issue should be fixed. I've not tested it but the board has undergone a fairly major redesign which includes an on-board switch to support for running directly of LiFePO4 batteries at 3.2v or, via the Regulator off normal 3.7v Li-ion.
The software for the ESP8266 is in this directory. It is fairly simple C code. The config.h file contains user-defined parameters. The ESP8266 code works like this: On power up the ESP attempts to connect to the WiFi network. If successful it then attempts to read the data back from the BME280 which provides, Temperature, Humidity and Pressure information. If the BME is read successfully the data is formatted and sent to the MQTT broker. The ESP8266 also sends infomration about it's supply voltage and the time it took to run this code loop. Finally the code puts the ESP into "Deep Sleep" for a preconfigured period.
The software is GPL, the OpenSCAD design of the case is Creative Commons Attribution-ShareAlike 4.0 International and the electronic designs are licenced using the Solderpad Hardware License version 0.51