ArdWeatherStation

This project is a LAN-based weather station using Arduino MCU (Adafruit Feather HUZZAH with ESP8266) clients and a server running on a Linux Docker container.

The goal is to have one outdoor MCU connected to a temperature and humidity sensor (Adafruit SHTC3), and another indoor MCU with an LCD screen to display the most recent sensor readings. A server program running on a desktop will communicate with both via WiFi. It will request readings from the sensor MCU at a given interval. It will also send those readings to the indoor MCU with the LCD screen in a similar interval.

(client_sensor) <-- (server) --> (client_display)

Notable Modules

• client_sensor
  • Contains the Arduino sketch for the temperature and humidity sensor MCU
• client_display
  • Contains the Arduino sketch for the MCU with display
• server
  • Contains the server program and Dockerfile

Module Overview

server

The server module utilizes the SocketServer class from the SimpleSocket library. It will run two SocketServer objects. One will interact directly with client_sensor and the other with the client_display. TCP will be used for each connection.

The server will convert the temperature value to Fahrenheit. The values to be shown by the client_display will be sent as a string with the readable text.

client_sensor

The client_sensor is connected to the SHTC3 temperature and relative humidity sensor. It will take a measurement when a reading is requested by the server and send it back in a defined struct.

client_display

The client_display is connected to an LCD display. It will receive measurements from the server and write them to the LCD.

Module Interaction

This section describes the steps of how readings from the client_sensor are displayed on the client_display, coordinated by the server.

1. server --> client_sensor

The server sends a measurement request with a byte-long message which is 0xB1.

2. client_sensor --> server

The temperature and relative humidity readings from the SHTC3 are of type float (32-bit). The client_sensor will send these values to the server using the sensor_readings_t struct.

typedef struct sensor_readings_t {
    float temp;
    float rel_hum;
} sensor_readings_t;

3. server --> client_display

The LCD client_display will have 16 columns and 2 rows, so the server will send the displayed string in a 33-byte array (+1 for the null byte).

char[33] lcd_display_text;

4. client_display --> server

Once the client_display receives the 32-byte array from the server, it will send byte 0xA2 to acknowledge.

Client and Server Connection Procedures

Each module will know the IP and destination port of its neighbor.

The client modules will attempt to connect to the server on boot-up. If a connection cannot be made or is lost, then they will try to reconnect at a short interval.

Similarly, the server will attempt to accept connections from both modules on boot-up, and try to reconnect if a connection is lost.