ESP12 1-Channel Relay with DS1307 RTC and 256kbit I2C memory IoT Controller Board

Description

Overview

The ESP-12 1-Channel Relay Controller Board is a compact 49 × 49 mm development and control board built around the ESP-12 Wi-Fi module. It combines a relay output with an DS1307 RTC and 24C256 I²C EEPROM, making it suitable for IoT controllers, access-control systems, timers, automation projects, and other embedded applications.

The board accepts a 5V power supply and includes an onboard AMS1117-3.3V regulator for the ESP-12 and 3.3V circuitry. The remaining ESP GPIOs are brought to convenient screw terminals for easy connection to external sensors, switches, and modules.

Key Features

• Based on ESP-12 Wi-Fi module
• Compact 49 × 49 mm PCB
• 1-channel relay output
  • Relay controlled by D0 / GPIO16
• Built-in DS1307 RTC for real-time clock and scheduling applications
• Built-in 24C256 I²C EEPROM for non-volatile data storage
• 5V power input
• Onboard AMS1117-3.3V regulator
• Screw terminals for convenient access to unused ESP GPIOs:
  • D5
  • D6
  • D7
  • D8
• Dedicated 6-pin programming header
• Programming header provides:
  • GP0
  • RST
  • TX
  • RX
  • 5V
  • GND
• Small footprint suitable for embedded installations and control enclosures

Programming Interface

The ESP-12 can be programmed directly through the onboard 6-pin header. The header provides the essential signals required for programming and serial communication:

GP0, RST, TX, RX, 5V, GND

This makes it convenient to connect a USB-to-serial programmer without needing to access the ESP-12 module directly.

Onboard Peripherals

Relay Output

The onboard relay is connected to D0 (GPIO16) and can be controlled by the ESP-12 firmware for switching external loads.

DS1307 RTC

The integrated DS1307 provides real-time clock functionality for applications requiring scheduled operations, time-based control, logging, or access management.

24C256 EEPROM

The 24C256 provides additional non-volatile memory for storing configuration parameters, schedules, counters, access-control data, or other user information.

Applications

• IoT relay controller
• Smart-home automation
• Access-control systems
• Time-based relay control
• Remote switching
• Door and gate controllers
• Data logging and configuration storage
• ESP8266 automation projects
• Custom embedded control systems

What’s Included

• 1 × ESP-12 1-Channel Relay Controller PCB
• ESP-12 module
• 1 × relay
• DS1307 RTC circuit (the 2032 Battery Sold alone)
• 24C256 EEPROM
• Onboard 5V-to-3.3V regulator

Notes

• Power input: 5V DC
• The board provides regulated 3.3V for the ESP-12 circuitry.
• External loads must be connected according to the relay’s contact ratings.
• The ESP-12 module, relay, RTC, and EEPROM are shown as assembled components in the pictured board.