WeMos D1 Temperature Sensor Nodes

Code https://github.com/ryanrdetzel/ESP8266-TempHum-Nodes
Test code https://github.com/ryanrdetzel/TemperatureHumidityCircuitTest

To complete my Zone Controller project I need a way to report various temperatures around the house. I currently have ways to measure temperatures using various home automation devices but I would prefer dedicated sensors that I can position precisely around the house.



The code is linked above. I want to keep it as simple as possible since this circuit will basically just do one thing, report the current temperature. The software should also be generic with no hardcoded values which will allow me to flash and upgrade all the nodes quickly. To achieve this I will store any settings in eeprom on the local chip once and the code will read these values when they're needed.

It would be a nice to be able to configure the nodes remotely but I'm not sure this is required just yet. For example, the sample rate, temperature offsets, etc might be useful to change without physically connecting the device. If I find I need this I might make a simple OTA way of changing config options.

Version 1

When I first started I didn't think that the temperature of the esp would affect the temperature, but I was wrong. This design looked good but it didn't work well because the sensor was enclosed with the IC and changed the temperature by a few degrees.

Version 2

For version 2 I moved the sensor away from the IC and into it's own area of the case. This helped and I even hot glued the opening to seal that up too. The sensors are still off by a few degrees compared to my other commercial sensors so I need to dive in more.

I started graphing the results of various sensors to see how close they were. As you can see from the graph below they are not that close. I manually calibrated them (with an offset) and that brought them closer but if I want accurate/precise measurements I'm going to have to do some more work.