ESP32-H2 Zigbee Water Meter

This project implements a Zigbee Water Meter using the ESP32-H2 and the ESP-IDF framework. It counts pulses from a standard water meter sensor (i.e. KH TL-W5MC1 5mm 5v), tracks total usage in liters, and reports the data to a Zigbee Coordinator (like Home Assistant w/ ZHA or Zigbee2MQTT) via the standard Metering Cluster.

Features

• Pulse Counting: Reads pulses on a GPIO pin (default: GPIO 13) to calculate water usage.
• Persistent Storage: Saves the total water count to NVS (Non-Volatile Storage), preserving data across reboots and power outages.
• Zigbee Metering Cluster:
  • Reports "Current Summation Delivered" (Total usage).
  • Configured for Cubic Meters ($m^3$) with a multiplier/divisor (1 pulse = 1 Liter = 0.001 $m^3$).
• Automatic Reporting: Sends updates to the coordinator when usage changes.
• Debouncing: Software debouncing (50ms) to prevent false counts from mechanical switches.

Hardware Requirements

1. ESP32-H2 Development Board (e.g., ESP32-H2-DevKitM-1).
2. Proximity sensor (TL-W5MC1): A sensor that outputs a pulse for every X amount of water (usually 1 pulse = 1 Liter).
3. Connecting Wires.

Wiring

Water Meter Sensor	ESP32-H2
Signal / Pulse	GPIO 13
GND	GND
VCC (if required)	3.3V or 5V (depending on sensor)

Note: The code enables the internal pull-up resistor on GPIO 13, so a simple reed switch connected between GPIO 13 and GND will work.

Software Requirements

• ESP-IDF v5.0+ (Recommended: v5.1 or v5.2 for ESP32-H2 support).
• Espressif Zigbee SDK (installed automatically via idf_component.yml).

Build and Flash

1. Install esp-idf at $HOME/esp/esp-idf

2. Set up the environment:

   . $HOME/esp/esp-idf/export.sh

3. Set the target:

   idf.py set-target esp32h2

4. Build the project:

   idf.py build

5. Flash and Monitor:

   idf.py flash monitor

How It Works

1. Pulse Counting

• A GPIO interrupt (gpio_isr_handler) triggers on the falling edge of the signal (connection to ground).
• The handler uses a 50ms debounce timer to ignore noise.
• Valid pulses increment a global total_liters_count.

2. Data Persistence

• A background task (update_task) runs every 1 second.
• If the count has changed, it:
  1. Updates the Zigbee stack's internal attribute value.
  2. Saves the new count to the NVS partition (water_count key).
• On boot, the system restores the last known count from NVS.

3. Zigbee Communication

• Role: End Device (ED).
• Cluster: Metering Cluster (0x0702).
• Attributes:
  • CurrentSummationDelivered (0x0000): The main reading.
  • UnitOfMeasure (0x0300): Cubic Meters.
  • Multiplier (0x0301): 1.
  • Divisor (0x0302): 1000.
  • (Result = Raw * 1 / 1000 = $m^3$).
• Reporting: The device is configured to report changes of at least 1 unit (1 liter) automatically.

Usage

1. Pairing:

   • On first boot, the device will automatically enter "Network Steering" mode to join an open Zigbee network.
   • Enable "Join" mode on your Zigbee Coordinator.
   • Monitor the logs; you should see Joined network successfully!.

2. Home Assistant / ZHA:

   • Once joined, it should appear as a "Water Meter" device.
   • It will report entities for the total summation.

3. Resetting:

   • The code handles factory reset signals if triggered via standard Zigbee commands (e.g., "Leave Network").
   • You can manually erase NVS (idf.py erase-flash) to reset the counter and network settings.