Temperature and humidity measuring published on mqtt

A micropython project for wemos d1 mini with wemos SHT30 sensor using mqtt as transport

The implementation of the sensor is taken from here SHT30

In order to use this an mqtt server must be set up. The one used for this project is mosquitto and has been setup to run on docker.

This project does not use authentication since it is build for a local deployment. If this does not work for you, edit accordingly.

This assumes that you are using a linux box and was done on one running ubuntu.

Physical Connection

The sensor is just stacked on top of the wemos d1. Keep in mind that it picks up temperature from the board so the reading is not true if used without some form of insulation. Even with insulation the sensor picks up a lot of heat from the board so the code puts the board in deepsleep instead of a while loop. The board waking from deep sleep reconnects to the wifi, to the mqtt sends the message, disconnects and sleeps again. For the board to wake up from deep sleep a connection has to be made between gpio16 (D0) and RST.

Configuration

Rename configuration_sample.json to configuration.json and edit accordingly. Everything else should just work out of the box.

To load this project the wemos d1 needs to be running micropython and you could probably use ampy.

Flashing micropython

Required tools:

esptool
micropython # Firmware for ESP8266 boards, get latest.

With the board connected to a usb port of your linux box assuming that the port is ttyUSB0 (check with dmesg after connecting to see what is assigned)

esptool.py --port /dev/ttyUSB0 erase_flash
esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20170108-v1.8.7.bin

I have had some d1 boards having trouble flashing with the above with garbage on the serial and the led staying on. On those boards this command works.

esptool.py --port /dev/ttyUSB0 write_flash -fm dio -fs 32m 0 esp8266-20170108-v1.8.7.bin

Loading the project

Required tools:

ampy

export AMPY_PORT=/dev/ttyUSB0
ampy put drivers/
ampy put configuration.json 
ampy put main.py 
ampy put boot.py 

Checking output

On an ubuntu box you can install mosquitto clients with:

sudo apt-get install mosquitto-clients

For other distros or platforms please search what is required. Checking messages:

mosquitto_sub -h MQTT_SERVER_IP -v -t "CONFIGURED_TOPIC"

should show something like this every however long the configuration is set to:

CONFIGURED_TOPIC {"humidity": 27.65392, "temperature": 27.68366}