ESP8266 weather station – design issues

Howdy there!

My weather station has been running for one night in the new housing and I already see the first issues coming up.

  1. Air flow
    The station has a Bosch BME280 for measuring humidity, temperature & pressure on board. While this sensor is extremely accurate (It once showed when I entered the lab one morning) it’s unfortunately 1-2 °C off.
    I blame the poor ventilation in the housing. Will need to do further testing.
  2. Solar measurement
    You probably noticed that I’ve got no clue electronics wise. I hooked up my PV panel to a voltage divider and connected it to my ADC. All is running fine until night. Then the ADC goes high beyond spec. This also happens if I connect the ADC directly to the ground. I would expect it to be zero – but what do I know?
    This doesn’t happen on the built-in ADC, only on the ADS1015. Needs more investigation.
    I don’t think it’s a problem since I’m not putting actual over-voltage into the ADC, but it’s an annoyance for sure.
  3. WiFi connectivity & power saving
    Currently the code is setup to wake up the ESP once in a while, connect to wifi and send a data sample. If there’s no wifi (and the ESP doesn’t have  that great of an antenna) it tries to connect over and over until it finally gets connected.
    This burns through my battery capacity (1400mAh) pretty quick (ESP 82mAh if not sleeping) and is totally unnecessary. Need to fix this. Which brings us to the next point:
  4. OTA – flashing firmware over the air. Not a major issue but it would be nice if I could just push the fix for 3) via WiFi instead of getting the unit in, opening it up, pulling out all the wiring and connecting it to my computer.
  5. Anemometer & deep sleep
    Measuring wind speed is more of a guess work with the current setup. Since the ESP is most of the time in deep sleep it wont notice if there is wind. Only when I wake it up and sample over 3 seconds I am able to detect if there’s some wind in exactly these 3 seconds. Proper way would be to run the anemometer much longer, like a minute but that would consume too much power. I probably need a separate uC (ATTiny?) for this which takes continues measurements, requires little power and then send it’s data to the ESP if asked.
  6. PCB
    I really need to get PCB printing setup and running again.
  7. Thingsboard
    I’m using thingsboard for data visualization and as MQTT broker and well… it was gone this morning. If your going to bet and are eager to see the sunrise in your data the next morning and the thing crashed just some minutes before sunrise –  not good.