- Arduino code running on a single ESP-01 (the tiny ESP8266 board).
JSON parsing of Weather Undergrounds's API to bring the temperature of a neighbor's PWS to my Blynk project. Plan to add a notification when outdoor temp equals indoor temp so I know I can open the doors and windows! I'll probably just add my own outdoor temp sensors as other PWSs don't seem to always be consistent or reliable.The API and parsing library worked just fine, but I could never find a Weather Underground station that had correct "microclimate" information. The local airport weather station always reported warmer, and a personal weather station in my neighborhood was unreliable. I switched to my own outdoor sensor!
Sooooo... I was getting worried. I love everything about the DS18B20 temperature sensor. Power flexibility, addressing, and bells and whistles that I haven't touched yet. However, I was getting unreliable readings... usually too high. After doing some reading I soon understood my problem: Heat transmission.
I was very proud of my stubby little temp sensor plugged directly into my hacked baby monitor (above), but it was always giving me temps around 5°C higher than other sensors in the same space. I noticed I was getting the same on my solderless breadboard but figured my work area was a little warmer.
Now check out this photo... I simply added about 8" of wire to my DS18B20 (CAT5e conductors to be exact):
I have reproduced this "phenomenon" with at least 3 sensors so far. Interesting! If adding a length of wire isn't possible for your project, experiment with correcting the temperature in code. This should work as long as the "localized heating" of your project is consistent.
## Libraries and Resources
| Title | Include | Link |
|---|---|---|
| OneWire | OneWire.h | https://github.com/PaulStoffregen/OneWire |
| Arduino-Temperature-Control-Library | DallasTemperature.h | https://github.com/milesburton/Arduino-Temperature-Control-Library |
| Time | Timelib.h | https://github.com/PaulStoffregen/Time |
| SimpleTimer | SimpleTimer.h | https://github.com/jfturcot/SimpleTimer |
| ESP8266/Arduino | ESP8266WiFi.h | https://github.com/esp8266/Arduino |
| blynk-library | BlynkSimpleEsp8266.h | https://github.com/blynkkk/blynk-library |
| ESP8266 board mgr | N/A | json & instructions |
Many thanks to the authors of the libraries above. How to edit this.