Relay Shield 4 channel & ESP32

An integrated ESP32 4-Channel Relay board is a single PCB that combines an ESP32 microcontroller module (like the ESP32-WROOM) and four electromechanical relays along with necessary supporting components (such as power regulation, optocouplers for isolation, and status LEDs).

This integrated design is popular for Internet of Things (IoT) and home automation projects because it:

• Simplifies Wiring and Assembly: By combining the microcontroller, Wi-Fi/Bluetooth connectivity, and the switching mechanism onto one board, it eliminates the need for messy external wiring between a separate ESP32 development board and a relay module. This results in a much cleaner, more reliable, and compact product.
• Space Efficiency: It has a smaller footprint than a setup with multiple separate components, making it easier to fit into enclosures or project boxes.
• Designed for Control: These boards are specifically designed for controlling high-power loads (like AC lights, motors, or appliances) up to their maximum rated capacity, typically around 10A at 250V AC or 30V DC per channel.
• Convenient Power Management: Many integrated boards include a power supply section that can accept a wider range of input voltages (e.g., 5V DC, 7-12V DC, or even 230V AC) and safely power both the ESP32 and the 5V relay coils.
• Isolation and Safety: Reputable designs often incorporate optocouplers to provide electrical isolation between the low-voltage control circuitry of the ESP32 and the high-voltage relay coils, which is a crucial safety feature.

Key Features

Typical features of an integrated ESP32 4-channel relay board often include:

• Microcontroller: Onboard ESP32 module (e.g., ESP32-WROOM-32E) for Wi-Fi and Bluetooth connectivity.
• Relays: Four independent relay channels, often rated at 10A.
• Relay Output: Screw terminals for easy connection to the high-power load's Common (COM), Normally Open (NO), and Normally Closed (NC) contacts.
• Power Input: Options like a DC jack or screw terminals for various power inputs.
• Programming: A USB port (Micro-USB or USB-C) for power and programming via the Arduino IDE or other frameworks (like ESP-IDF or ESPHome), sometimes requiring an external USB-to-TTL serial adapter.
• Indicators: LEDs to show power status and the on/off state of each relay.
• Expansion Ports: Accessible GPIO pins for connecting additional sensors, displays (like I2C OLEDs), or other peripherals.