Learn how to connect the Raspberry Pi Pico with the DS3231 RTC module using I2C for accurate real-time clock projects.
Interfacing Raspberry Pi Pico with DS3231 RTC
Keeping track of real-time data is essential for many embedded systems projects—whether you're building a data logger, digital clock, attendance system, or IoT device. In this tutorial, we’ll walk through how to interface the powerful Raspberry Pi Pico with the highly accurate DS3231 Real-Time Clock (RTC) module.
If you're looking to build time-based automation or timestamp sensor readings accurately, this guide is for you.
Why Use an External RTC with Raspberry Pi Pico?
The Raspberry Pi Pico, powered by the RP2040 microcontroller, does not include a built-in battery-backed real-time clock. That means it cannot retain time once power is removed.
This is where the DS3231 RTC module shines:
✅ High accuracy with temperature compensation
✅ Battery backup support
✅ I2C communication interface
✅ Low power consumption
The DS3231 maintains accurate time even during power failures, thanks to its onboard coin cell battery.
Components Required
To follow along with this project, you’ll need:
- Raspberry Pi Pico
- DS3231 RTC Module
- Breadboard
- Jumper wires
- Micro-USB cable
- CR2032 coin cell battery
- Understanding I2C Communication
The DS3231 communicates using the I2C protocol, which requires only two wires:
- SDA (Serial Data Line)
- SCL (Serial Clock Line)
The Raspberry Pi Pico supports multiple I2C interfaces, making it easy to connect peripherals like RTCs, sensors, displays, and more.
⚠️ Note: Ensure you are using 3.3V logic. The Pico operates at 3.3V, and most DS3231 modules support this voltage level.
MicroPython Code for Raspberry Pi Pico
To get started, install MicroPython firmware on your Raspberry Pi Pico. Then upload the following script:
This script initializes the I2C interface, reads the current date and time from the DS3231, and prints it to the serial monitor every second.
Setting the Time
To set the RTC manually, you can use:
Format:
Make sure you only set the time once; afterward, the battery backup will maintain it.
Applications of This Project
Interfacing the Raspberry Pi Pico with the DS3231 opens the door to countless practical projects:
📊 Data logging systems
⏰ Digital clocks
🌡️ Temperature & humidity loggers
🏫 Attendance tracking systems
🌐 IoT-based monitoring devices
Accurate timestamps make your projects reliable and professional.
Why This Matters for Embedded Developers
In embedded systems, timing is everything. Without a stable and persistent time source, many automation systems fail to operate correctly. By combining the Raspberry Pi Pico’s processing power with the DS3231’s precision, you can build robust time-aware applications.
Whether you're a beginner experimenting with microcontrollers or an advanced developer building production-ready systems, this setup is a must-know.
Final Thoughts
The Raspberry Pi Pico RTC DS3231 combination is simple, affordable, and powerful. With just four wires and a few lines of code, you can integrate accurate real-time functionality into your projects.
If you found this guide helpful, consider sharing it with fellow makers and embedded enthusiasts on Dev.to. More tutorials like this are on the way—covering IoT, sensors, automation, and advanced microcontroller projects. Explore 180+ DIY Raspberry Pi Pico Projects and Tutorials with Code and Schematics, featuring beginner-to-advanced projects with circuit diagrams, working videos, and complete Python code to build real-world applications.
Happy Building! 🚀
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