DS1307 Real Time Clock ( RTC ) Module

The DS1307 Real Time Clock (RTC) Module is a precision, low-power timekeeping board built around the popular DS1307 RTC IC from Maxim/Analog Devices. It accurately tracks seconds, minutes, hours (12/24-hour with AM/PM), day of the week, date, month, and year, with full leap year compensation valid through 2100.

The module communicates with any microcontroller using the simple two-wire I2C (TWI) interface, requiring only two signal pins (SDA and SCL) plus power and ground. This makes it extremely easy to integrate with Arduino, Raspberry Pi, ESP32, ESP8266, STM32, and PIC microcontrollers using widely available libraries such as RTClib.

A key feature of the DS1307 is its battery backup capability — the included LIR2032 coin cell keeps the clock running even when the main system power is removed, ensuring your time and date are always accurate when the device powers back on. The module also provides a 1Hz square wave output that can be used as a precise timing signal, hardware interrupt source, or wake-up trigger for low-power systems.

In addition to timekeeping, the DS1307 includes 56 bytes of battery-backed, non-volatile RAM that the user can read and write — useful for storing small amounts of configuration data or counters that need to survive power cycles.

The compact 28 × 25 × 10 mm form factor makes this module easy to integrate into clocks, data loggers, alarm systems, and any time-aware embedded project.

Specifications

• RTC IC: DS1307 (Maxim / Analog Devices)
• Communication Interface: I2C (Two-Wire)
• Time Tracking: Seconds, Minutes, Hours (12/24h with AM/PM)
• Calendar: Day, Date, Month, Year — with leap year compensation
• Battery Backup: LIR2032 rechargeable coin cell (included)
• User Memory: 56 bytes non-volatile battery-backed RAM
• Auxiliary Output: 1 Hz square wave output pin
• Operating Voltage: 5V DC (typical)
• Module Dimensions: 28 × 25 × 10 mm (approx.)
• Compatible With: Arduino, Raspberry Pi, ESP32, ESP8266, STM32, PIC, AVR, and others

Applications

• Real-time clocks and digital wall/desk clocks
• Data loggers with timestamped readings
• Alarms, timers, and scheduling systems
• Home automation and smart home controllers
• Attendance and access control systems
• Industrial control and process automation
• Weather stations and environmental monitoring
• Arduino, Raspberry Pi, and ESP32 projects requiring time awareness
• GPS-disciplined clock backup systems
• Educational STEM and electronics learning kits
• Medical devices and dosing reminders
• IoT time-stamped sensor networks