🚰 Water Flow Meter with SMS Alerts & EEPROM Logging

This project measures water flow, counts liters, and provides remote monitoring via SMS commands.
It uses an Arduino + flow sensor + GSM module + 24C256 I²C EEPROM to create a robust, low-power, field-ready solution.

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✨ Features

Accurate Water Flow Measurement

• Interrupt-driven pulse counter for precise flow tracking.

SMS Control & Monitoring

• Send GET → receive the total liters used.
• Send RESET → reset the counter.

Persistent Storage (24C256 EEPROM)

• Stores the water usage counter even after power loss.
• Sequence-numbered entries ensure the latest record is always found.
• Optimized page writes for endurance.

Non-blocking SMS Sending

• No more 5-second freezes when sending SMS.

Robust SMS Parsing & Deletion

• Reads only new messages.
• Deletes them after processing.

Data Safety

• Wraps counter updates in noInterrupts() for atomic operations.

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🛠️ Hardware Requirements

• Arduino Uno / Nano / Mega
• Water Flow Sensor (Hall-effect type, e.g., YF-S201)
• SIM800L / SIM900 GSM module
• 24C256 I²C EEPROM (AT24C256N or equivalent)
• Jumper wires, breadboard, stable power supply

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⚡ Wiring

EEPROM (AT24C256N, I²C)

Pin (EEPROM)	Arduino
VCC	5V
GND	GND
SDA	A4
SCL	A5
WP	GND

Flow Sensor

Pin	Arduino
VCC	5V
GND	GND
Signal	D2 (INT0)

GSM Module (SIM800L/SIM900)

Pin	Arduino
VCC	4V–5V (separate PSU recommended)
GND	GND
TX	D8 (SoftwareSerial RX)
RX	D9 (SoftwareSerial TX)

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📂 EEPROM Data Layout

Each record = 6 bytes:

• sequence (4 bytes, uint32_t)
• liters (2 bytes, uint16_t)

With 32 KB total:
That’s ~5,461 saves → with one save per liter, you get years of retention.

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📲 SMS Commands

• GET → returns the current water usage in liters.
• RESET → resets the counter to zero and saves it.

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🚦 How It Works

1. Flow sensor pulses are counted in an interrupt.
2. Every time the counter updates, it’s stored in EEPROM with a sequence number.
3. On startup → only the latest EEPROM entry is loaded.
4. GSM module listens for incoming SMS:
   • Parses and executes commands.
   • Sends back results using non-blocking SMS sending.
   • Deletes messages after processing.

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⚙️ Software Highlights

• EEPROM_Manager → handles sequence tracking, page writes, safe loads.
• FlowCounter ISR → atomic counting with noInterrupts().
• SMSHandler → parses messages, deletes after processing.
• NonBlockingSMS → allows loop to run while SMS is sending.

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🚀 Getting Started

1. Clone this repo:

   git clone https://github.com/yourname/water-flow-sms-meter.git
   cd water-flow-sms-meter