ESP32 Wi-Fi and MQTT to LoRa UART gateway bridging Home Assistant commands to remote garden watering solenoids.

![ESP32 MQTT-to-LoRa gateway controller connected to RA-01 radio module and solenoid water valve](docs/images/hero.png)

**Status: in progress**

### What it does
* Connects to Wi-Fi network and subscribes to Home Assistant MQTT topics (`homeassistant/ESP32/control`)
* Receives irrigation schedule triggers and valve pulse duration commands from Home Assistant
* Converts incoming MQTT messages into long-range LoRa packets over Serial2 (TX GPIO 17, RX GPIO 16)
* Controls remote battery-powered solenoid watering nodes across the garden without Wi-Fi coverage

### Bill of Materials
| Part | Quantity | Purpose |
| :--- | :---: | :--- |
| ESP32 Development Board | 1 | Microcontroller handling Wi-Fi, PubSubClient MQTT, and UART bridge |
| RA-01 LoRa SX1278 Module | 1 | 433MHz / 915MHz UART LoRa transceiver connected to Serial2 (pins 16/17) |
| 12V DC Solenoid Water Valve | 1 | Remote irrigation control valve operated by distant LoRa receiver node |
| MOSFET Driver / Relay Module | 1 | High-current valve actuator driver circuit on receiver node |

### How it works
The central ESP32 bridge stays connected to the local MQTT broker (`192.168.20.30`). When Home Assistant publishes a watering trigger to `homeassistant/ESP32/control`, the callback function captures the payload and immediately re-transmits it via UART (`Serial2` at 9600 baud on pins 16/17) to the RA-01 LoRa transmitter, reaching valves up to hundreds of meters away.

### What broke
* Software serial baud rate mismatches initially corrupted LoRa packets; switching to hardware UART (`Serial2` on GPIO 16/17) eliminated buffer overruns and frame drops.

### Links
* Gitea Repository: [sam/LoraMqttWatering](https://gitea.lab.audasmedia.com.au/sam/LoraMqttWatering)