I'm back on this project as a priority and making some headway. I began prototyping MCUs and sensors a few weeks ago and have created the following test bed/prototype:
- ESP8266 MCU (will be the controller of the Remote Terminal Unit)
- 32x128 OLED display (local readings and menu)
- Temperature/Humidity sensors (SHT11, DHT22 [AM2302], SHT35-DIS)
- Real Time Clock (RTC)
- AS3935 Lightning sensor
and I have an HX711 load cell sensor working. The load cell will be used for a subset of this project and used for bee hive monitoring.
All of the above components have been working together and I am now in the process of building a proper software framework for the final project code. Things have now gotten complex enough that I have begun outgrowing the "quick and dirty" code in the Arduino IDE. As a result I got an Eclipse instance working and installed the wonderful Sloeber plug-in. My future code development will be there.
I also have started a github repository where I will put any code that is not fully embarrassing, as well as project documentation and spreadsheets.
Status - most recently I began real-world testing of the DHT22 sensor, thinking it would be a less costly option for the bee hives. Sadly they fail fully in our weather.
Here in the Houston, Tx area we often have long periods of very high humidity. I have placed several DHT22s outdoors. They are under a roof so they are not subject to rain, any direct moisture and we are too far inland to have salt air.
Thus far all of them have begun giving false humidity readings after a day or two. Our typical day has been between 70% and 100% humidity with the temperature between 70F (21C) and 94F (34C).
[N.B., yes that is correct, our dewpoint has not been below 21C for the last 4 weeks or more]
In the failure mode the sensors continue to give humidity readings but the readings are about 15% RH too high.
It appears this is a saturation problem and basically renders them useless for anything except air conditioned spaces. I have not tried to recover them or recalibrate them because I want a reliable sensor and will not be using these for the foreseeable future.