AgXRP Sensor Kit Firmware

MicroPython firmware for the AgXRP — an automated plant monitoring and watering system built on the XRP (Experiential Robotics Platform) board. It monitors soil moisture and environmental conditions, logs data to CSV, and automatically controls peristaltic water pumps, all accessible through a local web dashboard.

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Features

• Real-time sensor monitoring — CO2, temperature, humidity, ambient light, spectral light, soil moisture
• Automatic watering — configurable thresholds, hysteresis, and intervals per plant/pump pair
• Web dashboard — live sensor readings and manual pump control at http://192.168.4.1
• Web configuration — edit all settings in the browser without touching code
• Data logging — periodic CSV sensor logs with automatic rotation; per-pump activity logs
• RTC synchronization — clock set from log file at boot, then synced precisely from the browser's local time when the dashboard is opened
• OLED display — rotating pages of sensor readings on an attached screen

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Hardware

• Board: XRP (RP2350-based)
• I2C Bus 0: SDA=GPIO4, SCL=GPIO5
• I2C Bus 1: SDA=GPIO38, SCL=GPIO39

Supported Sensors

Sensor	Type	Interface
SCD4x	CO2, temperature, humidity	I2C (Qwiic)
AS7343	16-channel spectral (blue/green/red/NIR)	I2C (Qwiic)
VEML	Ambient light intensity	I2C (Qwiic)
CY8CMBR3	Capacitive soil moisture (up to 4)	I2C (Qwiic)
Resistive soil	Soil moisture % (up to 4)	I2C (Qwiic)
Qwiic OLED	Display (micro or large)	I2C (Qwiic)

Water pumps connect to the XRP motor outputs (encoded motor channels 1–4).

Web Interface

Connect to the WiFi access point:

• SSID: AgXRP_SensorKit (default)
• Password: sensor123 (default)

Then open a browser to http://192.168.4.1

Page	URL	Description
Dashboard	/	Live sensor readings, manual pump control, plant system status
Configuration	/configure	Edit all settings, reboot device
Data Viewer	/data	Browse and download CSV log files

When the dashboard loads, it automatically syncs the device's RTC to your browser's local time, so all log timestamps are accurate.

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Configuration

All settings live in config.json. Key sections:

{
  "sensor_kit": {
    "bus0_enabled": true,       // I2C bus 0 (GPIO4/5)
    "bus1_enabled": true,       // I2C bus 1 (GPIO38/39)
    "i2c_freq": 100000
  },
  "sensors": {
    "co2":      { "enabled": true,  "bus": 0 },
    "spectral": { "enabled": false, "bus": 0 },
    "light":    { "enabled": true,  "bus": 0 },
    "screen":   { "enabled": true,  "bus": 0 },
    "soil": [
      { "enabled": true, "type": "capacitive", "sensor_index": 1, "bus": 1, "address": "0x37" }
    ],
    "csv_logger": { "enabled": false, "filename": "sensor_log.csv", "period_ms": 5000, "max_rows": 5000 }
  },
  "controller": {
    "enabled": true,
    "pumps": [
      { "enabled": true, "pump_index": 1, "csv_filename": "water_pump_1_log.csv", "max_duration_seconds": 60.0 }
    ],
    "plant_systems": [
      {
        "enabled": true,
        "sensor_index": 1,   // which soil sensor to watch
        "pump_index": 1,     // which pump to trigger
        "interval_hours": 0.5,
        "threshold": 300.0,  // water when reading exceeds this (pF for capacitive)
        "hysteresis": 20.0,  // don't re-trigger until reading drops this much below threshold
        "duration_seconds": 3.0,
        "pump_effort": 1.0   // 0.0–1.0
      }
    ]
  },
  "webserver": {
    "access_point": { "ssid": "AgXRP_SensorKit", "password": "sensor123" }
  },
  "sensor_update_interval_seconds": 2
}

All settings can also be edited live through the /configure web page — no file editing required.

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Project Structure

updated_firmware/
├── config.json                         # Hardware and control configuration
├── web_server.py                       # Main entry point
└── lib/
    ├── AgXRPLib/                       # AgXRP application library
    │   ├── agxrp_sensor_kit.py         # Sensor coordinator
    │   ├── agxrp_sensor_*.py           # Individual sensor wrappers
    │   ├── agxrp_water_pump.py         # Pump control and logging
    │   ├── agxrp_controller.py         # Automatic watering control loop
    │   ├── agxrp_csv_logger.py         # Periodic CSV data logging
    │   ├── agxrp_web_dashboard.py      # Web dashboard and API routes
    │   ├── agxrp_web_configure.py      # Web configuration page
    │   ├── agxrp_web_data_viewer.py    # CSV log viewer and download
    │   └── qwiic_*/                    # Hardware drivers (Qwiic sensors, OLED)
    ├── XRPLib/                         # XRP board drivers (motors, encoders, IMU, etc.)
    ├── phew/                           # MicroPython web framework (Pimoroni)
    ├── qwiic_i2c/                      # I2C abstraction layer
    └── ble/                            # Bluetooth UART / REPL (optional)

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Data Logging

When csv_logger is enabled, sensor readings are written to sensor_log.csv on the board filesystem at the configured interval. The file rotates to sensor_log.csv.bak when max_rows is reached.

Each pump writes a separate activity log (water_pump_1_log.csv, etc.) recording timestamp, revolutions, duration, and soil moisture at the time of watering.

Files can be downloaded from the /data page or retrieved directly with mpremote:

mpremote fs cp :sensor_log.csv ./sensor_log.csv

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Dependencies

All dependencies are bundled in lib/ — no package manager or internet connection required on the device.

• phew — MicroPython web framework by Pimoroni
• XRPLib — XRP board and motor control library
• qwiic_i2c — I2C abstraction layer for Qwiic sensors