# ClearGrow Probe

nRF52840-based wireless sensor probe for indoor growing environments. Communicates with the ClearGrow Controller via Thread mesh networking.

## Features

- **Thread MTD/SED**: Minimal Thread Device with Sleepy End Device support for battery optimization
- **Multi-Sensor Support**: Climate, leaf temperature, substrate, CO2, and PAR sensors
- **Code-Based Pairing**: Easy enrollment with controller via PSKd code
- **Low Power**: Deep sleep modes for extended battery life
- **CoAP Communication**: Efficient sensor data transmission via CoAP over Thread

## Hardware

- **MCU**: nRF52840 (ARM Cortex-M4F, 64MHz)
- **Radio**: IEEE 802.15.4 for Thread networking
- **Power**: 3.0V LiPo battery with USB charging
- **Sensors** (modular):
  - SHT4x: Temperature/humidity (climate)
  - MLX90614: IR leaf temperature
  - ADS1115: ADC for soil moisture/EC/pH
  - SCD4x: CO2 sensor
  - VEML7700: PAR/light sensor

## Project Structure

```
probe/
├── src/
│   ├── main.c              # Application entry point
│   ├── thread_node.c       # Thread networking and CoAP client
│   ├── sensor_manager.c    # Sensor polling and data aggregation
│   ├── power_manager.c     # Sleep modes and battery monitoring
│   └── pairing_code.c      # PSKd generation and storage
├── include/
│   └── probe_config.h      # Configuration and type definitions
├── boards/                 # Board-specific devicetree overlays
├── dts/                    # Devicetree source files
├── prj.conf                # Zephyr project configuration
├── Kconfig                 # Custom Kconfig options
└── CMakeLists.txt          # Build configuration
```

## Building

### Prerequisites

- Zephyr SDK 0.16.0 or later
- West build tool
- nRF Connect SDK (recommended)

### Setup

```bash
# Initialize west workspace (if not already done)
west init -m https://github.com/nrfconnect/sdk-nrf
west update

# Build for nRF52840 DK
west build -b nrf52840dk_nrf52840

# Flash
west flash
```

### Configuration

Key configuration options in `prj.conf`:

- `CONFIG_OPENTHREAD_MTD=y` - Minimal Thread Device mode
- `CONFIG_OPENTHREAD_JOINER=y` - Enable joiner for commissioning
- `CONFIG_PM=y` - Power management enabled

## Protocol

The probe sends sensor data to the controller using TLV (Type-Length-Value) format over CoAP:

**Packet Format:**
```
Header (12 bytes):
  [0-7]   Probe ID (EUI-64)
  [8]     Protocol Version
  [9]     Battery Percent
  [10-11] Sequence Number

Measurements (TLV, repeating):
  [Type]      Sensor type (1 byte)
  [ValueInfo] Type<<4 | Length (1 byte)
  [Value]     Sensor reading (1-4 bytes)
```

**Measurement Types:**
| Type | Sensor |
|------|--------|
| 0x01 | Temperature |
| 0x02 | Humidity |
| 0x03 | CO2 |
| 0x04 | PPFD |
| 0x05 | VPD |
| 0x06 | Leaf Temperature |
| 0x07 | Soil Moisture |
| 0x08 | Soil Temperature |
| 0x09 | EC |
| 0x0A | pH |
| 0x0B | DLI |
| 0x0C | Dew Point |

## License

Proprietary - ClearGrow Inc.