Adafruit
Adafruit PiRTC - Precise DS3231 Real Time Clock for Raspberry Pi
The Adafruit PiRTC Precise DS3231 is a high-accuracy, battery-backed real-time clock that plugs directly onto your Raspberry Pi's GPIO header. Built around a...
The Adafruit PiRTC Precise DS3231 is a high-accuracy, battery-backed real-time clock that plugs directly onto your Raspberry Pi's GPIO header. Built around a genuine Maxim DS3231 with an integrated temperature-compensated crystal oscillator (TCXO), it delivers exceptional timekeeping accuracy — far superior to standard crystal-based RTCs that drift with temperature changes.
The DS3231 achieves its precision by housing the crystal inside the chip alongside a temperature sensor that continuously compensates for frequency drift. This board uses 100% genuine Maxim DS3231 ICs purchased directly from the manufacturer, unlike many cheaper alternatives that use non-calibrated clones. It comes fully assembled with native Linux kernel support — just plug it in and configure.
Key Features
- Genuine Maxim DS3231 RTC – Temperature-compensated crystal oscillator for ±2 ppm accuracy (approximately ±1 minute per year)
- Plug-and-Play – Fully assembled; plugs directly onto the Pi GPIO header with no soldering
- I2C Interface – Native Raspberry Pi kernel driver support for easy setup
- Battery Backup – CR1220 coin cell slot keeps time through power loss for 5+ years
- Broad Compatibility – Works with any Raspberry Pi with a GPIO header (Pi 1, 2, 3, 4, 5, Zero, A+, B+)
Also Consider
- PiRTC PCF8523 – A more affordable option if high precision isn't required (±1–2 seconds/day drift)
Ideal For
- Precision data logging with accurate timestamps
- NTP servers and time-critical applications
- Offline Raspberry Pi setups without network time access
- Clock builds, alarms, and scheduled automation
Package Contents
- 1× Adafruit PiRTC DS3231 (fully assembled)
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- GPIO
- General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- ppm
- ppm means parts per million, a common way to express very small gas concentrations in air. For CO₂ sensors, the ppm range tells you what levels the sensor can measure, such as normal indoor air through to poorly ventilated spaces.
- RTC
- A Real-Time Clock keeps track of time even when the main processor is asleep or powered down, usually with a small backup battery. It matters for data logging and tracking projects that need accurate timestamps.
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Raspberry Pi
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