🌊 AquaSync — Automatic pH Stabilization System

AquaSync is an automatic system for keeping water pH stable, built with an ESP32, a pH 4502C sensor, and two dosing pumps (acid & base) controlled through an L298N motor driver. The system reads the water's pH periodically, and whenever the pH drifts outside the neutral range, the ESP32 automatically pumps the appropriate neutralizing solution (acid or base) in small, gradual doses (pulse dosing) until the pH stabilizes again.

All sensor data and pump status are sent in real time to a Flask-based web dashboard, so the water condition can be monitored directly from a browser — complete with a pH gauge, pump status, and reading history.

• 🧪 Real-time pH readings averaged over 20 ADC samples for stable results
• ⚖️ Hysteresis-based auto-dosing — prevents the pumps from rapidly toggling on/off near the threshold (threshold chattering)
• 💧 Pulse dosing — solution is pumped for a short burst followed by a mixing delay, preventing overdosing
• 🔒 Safety interlock — the acid and base pumps can never be active at the same time
• 📶 WiFi auto-reconnect if the connection drops
• 🖥️ Real-time web dashboard (auto-refreshes every 0.5 seconds) with a pH gauge, pump status, and a log of the last 5 readings
• 🟢 Online/offline status detection based on the time since the last data was received

The dashboard displays the real-time pH value, raw sensor voltage & ADC, the status of both pumps (base/acid), and a log of the last 5 pH readings along with the water condition (Acidic/Neutral/Basic).

📌 The full pin mapping (GPIO to each component) is available in docs/wiring.md.

┌──────────────┐ ADC Sampling ┌──────────────────┐
│ pH Sensor │ ───────────────────▶ │ ESP32 (Loop) │
└──────────────┘ (20 samples/2 sec) └──────────────────┘
 │
 pH < 6.5? │ pH > 8.5?
 ▼
 ┌─────────────────────┐
 │ Pulse Dosing State │
 │ Machine (Hysteresis)│
 └─────────────────────┘
 │
 Pump ON (2 sec) → OFF → Wait (5 sec)
 │
 ▼
 ┌─────────────────────┐
 │ HTTP POST /api/ │
 │ update → Flask Server│
 └─────────────────────┘
 │
 ▼
 ┌─────────────────────┐
 │ Web Dashboard │
 │ (auto-refresh 0.5s) │
 └─────────────────────┘

Hysteresis logic used:

The "buffer" range between the ON and OFF values prevents the pumps from rapidly switching on and off when the pH sits right at the threshold.

aquasync-ph-stabilizer/
├── firmware/
│ └── aquasync_firmware.ino # Main ESP32 code
├── server/
│ ├── app.py # Flask web server (dashboard + API)
│ └── requirements.txt
├── docs/
│ ├── wiring.md # GPIO pin mapping details
│ └── images/
├── .gitignore
├── LICENSE
└── README.md

cd server
pip install -r requirements.txt
python app.py

The server will run at http://<your-computer-IP>:5000. Open it in a browser to view the dashboard.

1. Open the firmware/aquasync_firmware.ino file in Arduino IDE
2. Install the required library: ArduinoJson
3. Configure below based on your address

   const char* WIFI_SSID = "YOUR_WIFI_SSID";
   const char* WIFI_PASSWORD = "YOUR_WIFI_PASSWORD";
   const char* SERVER_URL = "http://<your-computer-IP>:5000/api/update";

4. Upload aquasync_firmware.ino to the ESP32
5. Open the Serial Monitor (115200 baud) to view sensor reading logs

Use pH buffer solutions 4.01, 6.86, and 9.18 to calibrate the sensor, then adjust the PH_SLOPE and PH_INTERCEPT values in the firmware based on the voltage measured for each solution.

See the LICENSE file for details.

• Yunachz — GitHub