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Temperature Humidity Rain sensors

bonjour81 edited this page Apr 10, 2019 · 9 revisions

Temperature, Humidity & Rain are handled by a single ESP8266, supplied by Li-ion battery & Solar panel

1.Architecture

TH rain bloc diagram

2.ESP8266

A Wemos D1 mini pro is used as ESP8266 wifi. I will periodically get T&H values from HDC1010 and read the count of tipping bucket from PCF8583.

D0 (GPIO16) has to be connected to RST to use the energy saving 'deepsleep' mode.

3.PCF8583 & Davis 7852M rain gauge

The rain gauge is a Davis 7852M The tipping counter is a PCF8583 RTC IC from NXP.
It can be used as a counter by removing the crystal and use crystal pin as counter input.
A great Arduino library exists to read and clear the counter.

Connexion of the rain gauge to PCF8583 and ESP8266:

rain_details

Read the count can be done by RTC.getCount(); re-init can be done by RTC.setCount(0);

4.HDC1010.

HDC1010 is a high accuracy T & H sensor from TI. It is similar to HDC1080 except dust protection has been improved.

5.LIPO Rider

This board integrated a special lithium batteries charger for solar panel.
It integrate a so called "MPPT" function (maximum power point tracking). This function is made to deal with solar panel: it will take as much power as possible from solar panel to charge the battery.
The LIPO rider also integrate a boost to deliver 5V from the 3.7V battery.

Some improvement are possible here by replacing the 5V boost by a 3.3V powersupply (buck boost?) that can handle battery voltage as input. The efficiency would be improved compared to boost to 5V then LDO from 5 to 3.3V (on the wemos board).

6.INA219 Current measurement (optional)

It is not really necessary, but I have added a couple of INA219 to monitor battery & solar panel. Those modules mesures both voltage and current.

Datasheets

PCF8583 counter
HDC1010 T/H sensor INA219 current/voltage sensor

Links

PCF8583 Arduino lib including event counter function
Some useful information about rain gauge
LiPo Rider informations