Temperature Monitoring and Control System

Overview

This project is a temperature monitoring and control system built with an ESP32 microcontroller. It uses an LM35 temperature sensor to continuously monitor ambient temperature and automatically controls a relay to manage connected equipment (like cooling or heating systems). The system includes an OLED display for real-time information, LED indicators, alarm functionality, and Blynk IoT integration for remote monitoring and control.

Circuit Diagram

Features

• Real-time Temperature Monitoring: Uses LM35 temperature sensor for accurate readings
• Automatic Control: Activates/deactivates a relay based on configurable temperature thresholds
• Visual Feedback:
  • OLED display showing current temperature, system status, and relay state
  • LED indicators for relay status (ON/OFF)
• Audio Alerts: Different buzzer patterns for various states (overheat, recovery, system toggle)
• Manual Control: Physical button to toggle system operation
• Remote Monitoring and Control: Blynk IoT platform integration allows monitoring and control from anywhere
• Fail-safe Operation: System can work offline if WiFi/Blynk connection is unavailable

Hardware Requirements

• ESP32 development board
• LM35 temperature sensor
• 0.96" OLED display (SSD1306, I2C interface)
• 5V relay module
• Piezo buzzer
• 2 LEDs (for relay status indication)
• Push button
• Resistors and connecting wires
• 5V power supply

Software Dependencies

• Arduino IDE
• Libraries:
  • Wire.h - For I2C communication
  • Adafruit_GFX.h - Graphics library for the OLED display
  • Adafruit_SSD1306.h - Display driver for the OLED
  • WiFi.h - For WiFi connectivity
  • BlynkSimpleEsp32.h - For Blynk IoT platform integration
  • pitches.h - For buzzer tones

🛠️ Hardware Setup

Components

Component	ESP32 Pin
LM35 Sensor	GPIO34
Relay	GPIO5
Button	GPIO13
Buzzer	GPIO18
Relay ON LED	GPIO14
Relay OFF LED	GPIO12
OLED Display	I2C (0x3C)

Installation and Setup

1. Clone this repository or download the source code
2. Install required libraries through Arduino Library Manager
3. Create a Blynk account and set up a new project
4. Replace the following credentials in the code:

   #define BLYNK_TEMPLATE_ID "TMPL3MCE-W-US"
   #define BLYNK_TEMPLATE_NAME "TempControl"
   #define BLYNK_AUTH_TOKEN "rpbJiYaLbjx23ra69y84uos5Xge_dRlS"
   
   char ssid[] = "your-wifi-ssid";
   char pass[] = "your-wifi-password";
   
   
   

Blynk Project Setup

In your Blynk app:

1. Create a new project
2. Add the following widgets with corresponding virtual pins:
   • Value Display (V0): For temperature readings
   • Value Display (V1): For relay status
   • Value Display (V2): For system status
   • Value Display (V3): For voltage
   • Value Display (V4): For overheat status
   • Button (V5): For toggling system on/off

Operation

• Normal Operation: When temperature is below threshold (30°C), the relay is ON
• Overheat Condition: When temperature exceeds threshold, relay turns OFF and alarm sounds
• Manual Control: Press the physical button to toggle system ON/OFF
• Remote Control: Use the Blynk app to monitor and control the system

Customization

• Temperature threshold can be adjusted by changing const float temperatureThreshold = 30.0;
• Alarm sounds and durations can be modified in the corresponding arrays
• Update intervals can be adjusted for different components:
  • Temperature reading: const unsigned long updateInterval = 2000;
  • Blynk updates: const unsigned long blynkUpdateInterval = 1000;

Troubleshooting

• If the OLED display fails to initialize, check the I2C connections and address
• If Blynk connection fails, the system will operate in offline mode
• For inaccurate temperature readings, check the LM35 sensor connections and power supply

License

This project is licensed under the MIT License. Hack it, share it, just give a shoutout to the original repo.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Acknowledgments

• Adafruit for their excellent display libraries
• Blynk for their IoT platform