# ZNET LoRa Remote Sensor Node

Battery-powered sensor nodes that transmit temperature, humidity, and air quality data to the ZNET gateway via LoRa.

## Supported Hardware

| Board | Chip | LoRa | Notes |
|-------|------|------|-------|
| Heltec WiFi LoRa 32 V3 | ESP32-S3 | SX1262 | Recommended - built-in OLED |
| TTGO LoRa32 V2.1 | ESP32 | SX1276 | Budget option |
| DIY ESP32 + SX1276 | ESP32 | SX1276 | Full customization |

## Supported Sensors

| Sensor | Data | Use Case |
|--------|------|----------|
| DHT22 | Temp + Humidity | Ambient monitoring |
| BME680 | Temp + Humidity + Pressure + Gas | Air quality monitoring |
| DS18B20 | Temperature (high precision) | Remote tank monitoring |

## Quick Start

### 1. Install PlatformIO

```bash
pip install platformio
```

### 2. Configure Node

Edit `include/config.h`:

```cpp
// Set unique node ID or use 0xFFFF for auto-assign
#define NODE_ID 0x0101

// Node name (max 8 chars)
#define NODE_NAME "Ambient1"

// Report interval (seconds)
#define REPORT_INTERVAL_SEC 60
```

### 3. Build & Upload

```bash
cd remote-node

# For Heltec V3 with DHT22:
pio run -e heltec_v3_dht22 --target upload

# For Heltec V3 with BME680:
pio run -e heltec_v3_bme680 --target upload

# For TTGO board:
pio run -e ttgo_lora32_v21 --target upload
```

### 4. Monitor Output

```bash
pio device monitor
```

## Wiring

### DHT22 Sensor

```
ESP32 GPIO7 ─────────── DHT22 DATA
ESP32 3.3V ──────────── DHT22 VCC
ESP32 GND ───────────── DHT22 GND

10kΩ pullup between DATA and VCC
```

### BME680 Sensor (I2C)

```
ESP32 SDA (21) ──────── BME680 SDA
ESP32 SCL (22) ──────── BME680 SCL
ESP32 3.3V ──────────── BME680 VCC
ESP32 GND ───────────── BME680 GND
```

### Battery Connection

```
LiPo + ─────┬───────── ESP32 VBAT
            │
           ┌┴┐
           │ │ 100kΩ
           └┬┘
            ├───────── ADC Pin (Battery monitoring)
           ┌┴┐
           │ │ 100kΩ
           └┬┘
            │
LiPo - ─────┴───────── ESP32 GND
```

## Power Consumption

| State | Current | Notes |
|-------|---------|-------|
| Deep Sleep | ~10 μA | ESP32 deep sleep |
| Active (reading) | ~15 mA | Sensor reading |
| TX | ~80 mA | LoRa transmission |
| **Average @ 60s** | **~1 mA** | Typical |

### Battery Life Estimates (1000mAh LiPo)

| Interval | Battery Life |
|----------|--------------|
| 30 sec | ~2 weeks |
| 60 sec | ~1 month |
| 5 min | ~6 months |
| 10 min | ~1 year |

## Protocol

See [../docs/LORA_PROTOCOL.md](../docs/LORA_PROTOCOL.md) for full LoRa packet specification.

### Node ID Ranges

| Range | Purpose |
|-------|---------|
| 0x0001-0x00FF | Tank sensors |
| 0x0100-0x01FF | Ambient (DHT22) |
| 0x0200-0x02FF | Environmental (BME680) |
| 0xFFFF | Auto-assign |

## Troubleshooting

### No LoRa transmission

1. Check LoRa frequency matches gateway (915 MHz for US)
2. Verify SPI pins are correct for your board
3. Check serial monitor for "LoRa init failed" errors

### Sensor read fails

1. Check wiring connections
2. Verify correct GPIO pins in config.h
3. For I2C sensors, run I2C scanner to verify address

### Short battery life

1. Increase `REPORT_INTERVAL_SEC`
2. Disable OLED (`ENABLE_OLED 0`)
3. Disable serial debug in production (`ENABLE_SERIAL_DEBUG 0`)

### Not receiving ACKs

1. Verify gateway is running and receiving
2. Check sync word matches (0x12)
3. Reduce spreading factor if range is short (better reliability)