The ESP32 Smart Plug allows users to turn appliances on/off, schedule operation times, and monitor power consumption. It communicates via Wi-Fi and integrates with mobile apps or cloud-based platforms.

Wireless Control: Operate appliances using an IoT app (e.g., Blynk, Home Assistant, or custom app).

Power Isolation: Uses an optocoupler and relay for safe switching of high-power loads.

Compact PCB Design: Optimized for fitting inside a standard wall plug enclosure.

LED Indicator: Shows the status of the smart plug.

Safety Mechanisms: Includes a diode for protection and resistors for proper voltage regulation.

Components used in Smart Plug PCB Design Project:

Here’s how each component contributes to the Smart Plug PCB Design:

Microcontroller Unit:

• ESP32
  • Acts as the main controller.
  • Connects to Wi-Fi for remote control.
  • Sends control signals to the relay for switching appliances.

Power Supply Components:

• HLK-10M05
  • A 5V power supply module that converts AC mains to 5V DC for ESP32 and other components.
• POWER SOLDERING PAD 2.0
  • Used for high-current connections and providing proper soldering space for power lines.

Switching and Isolation:

• PC817X2NSZ9F (Optocoupler)
  • Provides electrical isolation between ESP32 and the high-voltage relay.
  • Ensures safe operation and protects the microcontroller from voltage spikes.
• SRA-05VDC-CL (Relay)
  • A 5V relay module that switches high-power appliances on/off.
  • Controlled by ESP32 via an optocoupler.

Transistors and Diodes:

• BC847C (NPN Transistor)
  • Works as a switching transistor to control the relay circuit.
  • Provides additional current amplification.
• 1N4007_C727081 (Diode)
  • A flyback diode that protects the circuit from voltage spikes caused by the relay coil.

Resistors and Indicators:

• 1kΩ and 510Ω Resistors
  • Used for current limiting in various parts of the circuit, including the optocoupler and transistor.
• LTST-C170KSKT (LED Indicator)
  • A status LED that provides a visual indication of whether the smart plug is ON or OFF.

Connector:

• PM254-1-19-Z-8.5 (Terminal Block)
  • Used for connecting the relay output to external electrical appliances safely.

Working Principle of Smart Plug:

Power Supply:

• The HLK-10M05 module converts AC 220V (or 110V) to 5V DC for the ESP32 and relay circuit.

Microcontroller Control:

• The ESP32 is programmed to control the relay based on commands received via Wi-Fi.

Optocoupler Isolation:

• The PC817 optocoupler ensures safe signal transmission between the ESP32 and the relay.

Relay Activation:

• The BC847C transistor acts as an intermediate switch, enabling the SRA-05VDC-CL relay to turn the appliance ON/OFF.

Feedback and Status Indication:

• The LTST-C170KSKT LED indicates whether the plug is ON or OFF.
• A mobile app can be used to monitor and control the plug.

Pictures of Smart Plug PCB:

Applications of Smart Plug PCB:

Smart Home Automation – Remotely control appliances like fans, lamps, or heaters.

Energy Management – Schedule devices to reduce power consumption.

Industrial Use – Control heavy-duty electrical loads with safety.

Conclusion:

This ESP32 Smart Plug PCB integrates essential power management, isolation, and wireless communication features. The compact design ensures easy installation in standard enclosures, making it a reliable IoT home automation solution.