Espressif ESP32 Circuit
Overview
This circuit will serve as the communication have a microcontroller with WiFi and BLE (Bluetooth Low Energy) capabilities. It will also have Radio communication capability for data exchange with the other two circuits. This circuit will send all sensor data to the IoT platform or the MQTT broker over WiFi and to the mobile app over BLE. It will receive control signals from the mobile app over BLE and remotely via MQTT over WiFi. It will receive sensor data and send control signals to the other two circuits over Radio communication.
This circuit is not required for the Node-RED variant of the solution since the Nano and Pico circuits will be directly connected with USB cables to the computer running Node-RED which will exchange data with the circuits and the MQTT broker. In this variant there will be no BLE communication with the mobile app.
Components
| Component Name | Purpose | Voltage | Ouput/Communication |
|---|---|---|---|
| DS3231 | Real-time clock module | 3.3V | I2C |
| SX1278 RA-02 | LoRa communication module | 3.3V | SPI (plus an NSS pin) |
| OLED Display | Used to display data | 5V | I2C |
| I2C LCD 16x2 | Used to display data | 5V | I2C |
| LED | Used as an indicator | 5V | Digital Out (use a resistor to limit the current) |