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Adafruit 5188 DS3231 Precision RTC - STEMMA QT
The Adafruit 5188 DS3231 Precision Real-Time Clock module is an I2C-based timekeeping solution featuring the industry-leading DS3231 temperature-compensated crystal oscillator, delivering accuracy within ±2ppm across operating temperatures. Electronics engineers, IoT developers, and embedded systems designers rely on this module to maintain precise time synchronization in data logging systems, autonomous vehicles, industrial controllers, and networked devices where NTP connectivity is unavailable. This module solves the critical problem of time drift in battery-backed systems by providing sub-second accuracy without external network dependencies, eliminating the need for manual clock adjustment in remote or offline applications.
Product Overview
The DS3231 is a low-cost, extremely accurate I2C real-time clock with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The module operates on a single 3.3V to 5V supply and communicates via the I2C protocol at standard 100kHz or fast 400kHz speeds. The DS3231 contains a 32-byte battery-backed SRAM for storing user data, allowing critical variables to persist through power cycles. The integrated temperature sensor compensates for crystal frequency variations, maintaining accuracy within ±2ppm from -40°C to +85°C, making it suitable for industrial and automotive applications where temperature stability is paramount.
The Adafruit 5188 breakout board features a convenient STEMMA QT connector for plug-and-play integration with compatible microcontroller platforms including Arduino, Raspberry Pi, and Adafruit microcontroller boards. The module includes a CR2032 coin cell battery holder for continuous timekeeping during power loss, ensuring the RTC maintains accurate time for extended periods without main power. The compact form factor and pre-configured I2C address (0x68) simplify integration into space-constrained applications, while the open-source Arduino library support accelerates development cycles for both hobbyists and professional engineers.
Key Specifications
| Specification | Details |
| Product Type | Precision Real-Time Clock Module with Temperature Compensation |
| Brand | Adafruit Industries |
| Origin | Original/Authentic |
| Warranty | 7 days on manufacturing defects |
| Shipping | 1-5 days from Bengaluru |
| Delivery | 7-8 days across India |
| Support | 24/7 via Email and WhatsApp |
| RTC Chip | DS3231 Temperature-Compensated Crystal Oscillator |
| Accuracy | ±2ppm across -40°C to +85°C operating range |
| Communication Protocol | I2C (100kHz standard, 400kHz fast mode supported) |
| Default I2C Address | 0x68 |
| Operating Voltage | 3.3V to 5V DC |
| Battery Backup | CR2032 coin cell holder for continuous operation during power loss |
| Battery-Backed SRAM | 32 bytes for user data persistence |
| Connector Type | STEMMA QT (JST SH 4-pin) for plug-and-play integration |
| Temperature Sensor | Integrated with ±3°C accuracy |
Key Features
- Temperature-Compensated Accuracy: DS3231 maintains ±2ppm accuracy across full temperature range, eliminating the need for manual calibration in thermally variable environments
- STEMMA QT Connector: Solderless plug-and-play connectivity with Arduino, Raspberry Pi, and Adafruit microcontroller boards reduces integration time and prototyping complexity
- Battery-Backed Operation: Integrated CR2032 holder ensures continuous timekeeping for months during power loss, critical for autonomous data logging and event timestamping
- Dual Alarm Functions: Hardware-level alarm triggers enable interrupt-driven wake-up sequences and scheduled event execution without firmware overhead
- 32-Byte SRAM: Battery-backed memory storage preserves configuration data, calibration offsets, and system state across power cycles
- Wide Supply Range: Operates reliably from 3.3V to 5V, compatible with both legacy 5V Arduino platforms and modern 3.3V microcontroller boards
- Square Wave Output: Programmable 1Hz, 4kHz, 8kHz, or 32kHz output enables external frequency reference applications and synchronization of multiple timing-critical systems
Applications and Use Cases
- Data Logging and Environmental Monitoring: Precise timestamp generation for sensor readings in weather stations, air quality monitors, and industrial IoT systems where UTC synchronization is unavailable
- Autonomous Vehicle Navigation: Provides accurate time references for GPS-denied navigation systems, sensor fusion algorithms, and event sequencing in robotics applications
- Battery-Powered IoT Devices: Maintains time accuracy in remote sensors and edge devices operating on coin cell or solar power without network connectivity
- Industrial Process Control: Enables accurate event scheduling, alarm triggering, and audit trail timestamping in manufacturing systems, HVAC controllers, and building automation platforms
- Embedded Medical Devices: Delivers reliable timekeeping for medication reminders, patient monitoring systems, and diagnostic equipment requiring precise temporal correlation of physiological measurements
- Financial and Security Systems: Provides tamper-resistant time references for transaction logging, access control systems, and cryptographic timestamp generation in offline environments
How to Use
Connect the Adafruit 5188 to your microcontroller using the STEMMA QT connector, which carries SDA and SCL I2C lines plus power and ground. Install the Adafruit RTClib Arduino library from the Library Manager and include the header file in your sketch. Initialize the RTC object with address 0x68 and verify communication via I2C bus scanning. If the RTC has lost power, set the current time using the adjust() function with a DateTime object, then the module will maintain accurate time indefinitely through the integrated crystal oscillator and battery backup system.
For optimal performance, insert a fresh CR2032 battery into the holder to enable continuous operation during power loss. Configure alarm functions using setAlarm1() or setAlarm2() methods to trigger interrupts at specific times or intervals, useful for scheduled wake-ups in low-power applications. The square wave output can be enabled and configured for external frequency reference applications. Monitor the temperature sensor reading periodically to verify the TCXO compensation is functioning correctly. The battery-backed SRAM can store calibration offsets or system configuration using the read() and write() methods, allowing persistence of critical parameters across power cycles without external EEPROM.
Frequently Asked Questions
What is the accuracy specification and how does temperature compensation work?
The DS3231 maintains ±2ppm accuracy across the full -40°C to +85°C operating range through integrated temperature compensation. The module contains a temperature sensor that continuously monitors crystal frequency drift and applies digital correction to the oscillator. This TCXO approach eliminates the need for external calibration or manual adjustment, making it superior to standard crystal oscillators that drift significantly with temperature variations. At room temperature, typical accuracy is within ±5 seconds per year, suitable for professional timekeeping applications.
Can this RTC module work with 5V and 3.3V microcontrollers simultaneously?
Yes, the Adafruit 5188 operates reliably on supply voltages from 3.3V to 5V. The I2C bus uses open-drain outputs, so it works with both 3.3V and 5V logic levels without additional level shifters. However, ensure your microcontroller I2C pins are 5V tolerant if powering the RTC from 5V, or use a level shifter between 5V logic and 3.3V I2C lines. The STEMMA QT connector carries the supply voltage you provide, so select 3.3V or 5V based on your microcontroller requirements.
How long will the CR2032 battery maintain timekeeping during power loss?
A fresh CR2032 battery typically provides 6 to 12 months of continuous timekeeping when the main power is disconnected. Battery life depends on ambient temperature, with shorter duration at higher temperatures due to increased leakage current. The DS3231 draws approximately 3-5 microamps from the backup battery during standby, making it extremely efficient. Replace the battery annually in critical applications or if you notice time loss after extended power outages. The module will continue to function normally on main power even with a dead backup battery, but will lose time during power loss.
What I2C address does this module use and can it be changed?
The DS3231 has a fixed I2C address of 0x68 (104 in decimal), which cannot be modified via hardware or software. If you need multiple RTC modules on the same I2C bus, you must use an I2C multiplexer or separate I2C buses on your microcontroller. The fixed address design ensures reliability and prevents accidental address conflicts in complex systems, though it limits the number of RTC modules per bus to one.
How do I set the time and ensure it stays accurate after power loss?
Use the RTClib adjust() function with a DateTime object representing the current time: rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); or rtc.adjust(DateTime(2024, 1, 15, 14, 30, 0)); for manual time setting. Once set, the RTC maintains accurate time through the crystal oscillator. During power loss, the CR2032 battery keeps the RTC running. When power returns, the RTC continues from the correct time without resetting. Verify battery voltage periodically and replace the CR2032 annually to ensure uninterrupted operation.
When will I receive my order?
Orders are dispatched within 1-5 business days from our Bengaluru warehouse. Delivery takes 7-8 days to most locations across India.
What is your return and warranty policy?
We offer a 7-day return policy on manufacturing defects only. Contact support within 7 days of receipt for free replacement or full refund. Not applicable for user damage or misuse.
Are bulk discounts available?
Yes, wholesale pricing for orders of 10 or more units. Contact our sales team via WhatsApp or email for a customized bulk quote.
Why Buy from The Engineer Store
- Genuine Products: Sourced directly from authorized distributors with authentication
- Expert Team: Our technical team validates every product before listing
- Fast Shipping: Dispatched within 1-5 days from our Bengaluru warehouse
-
Buy Adafruit 5188 DS3231 Precision RTC - STEMMA QT Online in India
Purchase the Adafruit 5188 DS3231 Precision RTC - STEMMA QT online at The Engineer Store, India's trusted source for genuine electronics. We deliver across Bengaluru, Mumbai, Delhi, Chennai, Hyderabad, Pune, Kolkata, Ahmedabad, Jaipur, and Surat.
Our team in Bengaluru is available 24/7 to support your journey from product selection to project completion.
Adafruit 5188 DS3231 Precision RTC - STEMMA QT
The Adafruit 5188 DS3231 Precision Real-Time Clock module is an I2C-based timekeeping solution featuring the industry-leading DS3231 temperature-compensated crystal oscillator, delivering accuracy within ±2ppm across operating temperatures. Electronics engineers, IoT developers, and embedded systems designers rely on this module to maintain precise time synchronization in data logging systems, autonomous vehicles, industrial controllers, and networked devices where NTP connectivity is unavailable. This module solves the critical problem of time drift in battery-backed systems by providing sub-second accuracy without external network dependencies, eliminating the need for manual clock adjustment in remote or offline applications.
Product Overview
The DS3231 is a low-cost, extremely accurate I2C real-time clock with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The module operates on a single 3.3V to 5V supply and communicates via the I2C protocol at standard 100kHz or fast 400kHz speeds. The DS3231 contains a 32-byte battery-backed SRAM for storing user data, allowing critical variables to persist through power cycles. The integrated temperature sensor compensates for crystal frequency variations, maintaining accuracy within ±2ppm from -40°C to +85°C, making it suitable for industrial and automotive applications where temperature stability is paramount.
The Adafruit 5188 breakout board features a convenient STEMMA QT connector for plug-and-play integration with compatible microcontroller platforms including Arduino, Raspberry Pi, and Adafruit microcontroller boards. The module includes a CR2032 coin cell battery holder for continuous timekeeping during power loss, ensuring the RTC maintains accurate time for extended periods without main power. The compact form factor and pre-configured I2C address (0x68) simplify integration into space-constrained applications, while the open-source Arduino library support accelerates development cycles for both hobbyists and professional engineers.
Key Specifications
| Specification | Details |
| Product Type | Precision Real-Time Clock Module with Temperature Compensation |
| Brand | Adafruit Industries |
| Origin | Original/Authentic |
| Warranty | 7 days on manufacturing defects |
| Shipping | 1-5 days from Bengaluru |
| Delivery | 7-8 days across India |
| Support | 24/7 via Email and WhatsApp |
| RTC Chip | DS3231 Temperature-Compensated Crystal Oscillator |
| Accuracy | ±2ppm across -40°C to +85°C operating range |
| Communication Protocol | I2C (100kHz standard, 400kHz fast mode supported) |
| Default I2C Address | 0x68 |
| Operating Voltage | 3.3V to 5V DC |
| Battery Backup | CR2032 coin cell holder for continuous operation during power loss |
| Battery-Backed SRAM | 32 bytes for user data persistence |
| Connector Type | STEMMA QT (JST SH 4-pin) for plug-and-play integration |
| Temperature Sensor | Integrated with ±3°C accuracy |
Key Features
- Temperature-Compensated Accuracy: DS3231 maintains ±2ppm accuracy across full temperature range, eliminating the need for manual calibration in thermally variable environments
- STEMMA QT Connector: Solderless plug-and-play connectivity with Arduino, Raspberry Pi, and Adafruit microcontroller boards reduces integration time and prototyping complexity
- Battery-Backed Operation: Integrated CR2032 holder ensures continuous timekeeping for months during power loss, critical for autonomous data logging and event timestamping
- Dual Alarm Functions: Hardware-level alarm triggers enable interrupt-driven wake-up sequences and scheduled event execution without firmware overhead
- 32-Byte SRAM: Battery-backed memory storage preserves configuration data, calibration offsets, and system state across power cycles
- Wide Supply Range: Operates reliably from 3.3V to 5V, compatible with both legacy 5V Arduino platforms and modern 3.3V microcontroller boards
- Square Wave Output: Programmable 1Hz, 4kHz, 8kHz, or 32kHz output enables external frequency reference applications and synchronization of multiple timing-critical systems
Applications and Use Cases
- Data Logging and Environmental Monitoring: Precise timestamp generation for sensor readings in weather stations, air quality monitors, and industrial IoT systems where UTC synchronization is unavailable
- Autonomous Vehicle Navigation: Provides accurate time references for GPS-denied navigation systems, sensor fusion algorithms, and event sequencing in robotics applications
- Battery-Powered IoT Devices: Maintains time accuracy in remote sensors and edge devices operating on coin cell or solar power without network connectivity
- Industrial Process Control: Enables accurate event scheduling, alarm triggering, and audit trail timestamping in manufacturing systems, HVAC controllers, and building automation platforms
- Embedded Medical Devices: Delivers reliable timekeeping for medication reminders, patient monitoring systems, and diagnostic equipment requiring precise temporal correlation of physiological measurements
- Financial and Security Systems: Provides tamper-resistant time references for transaction logging, access control systems, and cryptographic timestamp generation in offline environments
How to Use
Connect the Adafruit 5188 to your microcontroller using the STEMMA QT connector, which carries SDA and SCL I2C lines plus power and ground. Install the Adafruit RTClib Arduino library from the Library Manager and include the header file in your sketch. Initialize the RTC object with address 0x68 and verify communication via I2C bus scanning. If the RTC has lost power, set the current time using the adjust() function with a DateTime object, then the module will maintain accurate time indefinitely through the integrated crystal oscillator and battery backup system.
For optimal performance, insert a fresh CR2032 battery into the holder to enable continuous operation during power loss. Configure alarm functions using setAlarm1() or setAlarm2() methods to trigger interrupts at specific times or intervals, useful for scheduled wake-ups in low-power applications. The square wave output can be enabled and configured for external frequency reference applications. Monitor the temperature sensor reading periodically to verify the TCXO compensation is functioning correctly. The battery-backed SRAM can store calibration offsets or system configuration using the read() and write() methods, allowing persistence of critical parameters across power cycles without external EEPROM.
Frequently Asked Questions
What is the accuracy specification and how does temperature compensation work?
The DS3231 maintains ±2ppm accuracy across the full -40°C to +85°C operating range through integrated temperature compensation. The module contains a temperature sensor that continuously monitors crystal frequency drift and applies digital correction to the oscillator. This TCXO approach eliminates the need for external calibration or manual adjustment, making it superior to standard crystal oscillators that drift significantly with temperature variations. At room temperature, typical accuracy is within ±5 seconds per year, suitable for professional timekeeping applications.
Can this RTC module work with 5V and 3.3V microcontrollers simultaneously?
Yes, the Adafruit 5188 operates reliably on supply voltages from 3.3V to 5V. The I2C bus uses open-drain outputs, so it works with both 3.3V and 5V logic levels without additional level shifters. However, ensure your microcontroller I2C pins are 5V tolerant if powering the RTC from 5V, or use a level shifter between 5V logic and 3.3V I2C lines. The STEMMA QT connector carries the supply voltage you provide, so select 3.3V or 5V based on your microcontroller requirements.
How long will the CR2032 battery maintain timekeeping during power loss?
A fresh CR2032 battery typically provides 6 to 12 months of continuous timekeeping when the main power is disconnected. Battery life depends on ambient temperature, with shorter duration at higher temperatures due to increased leakage current. The DS3231 draws approximately 3-5 microamps from the backup battery during standby, making it extremely efficient. Replace the battery annually in critical applications or if you notice time loss after extended power outages. The module will continue to function normally on main power even with a dead backup battery, but will lose time during power loss.
What I2C address does this module use and can it be changed?
The DS3231 has a fixed I2C address of 0x68 (104 in decimal), which cannot be modified via hardware or software. If you need multiple RTC modules on the same I2C bus, you must use an I2C multiplexer or separate I2C buses on your microcontroller. The fixed address design ensures reliability and prevents accidental address conflicts in complex systems, though it limits the number of RTC modules per bus to one.
How do I set the time and ensure it stays accurate after power loss?
Use the RTClib adjust() function with a DateTime object representing the current time: rtc.adjust(DateTime(F(__DATE__), F(__TIME__))); or rtc.adjust(DateTime(2024, 1, 15, 14, 30, 0)); for manual time setting. Once set, the RTC maintains accurate time through the crystal oscillator. During power loss, the CR2032 battery keeps the RTC running. When power returns, the RTC continues from the correct time without resetting. Verify battery voltage periodically and replace the CR2032 annually to ensure uninterrupted operation.
When will I receive my order?
Orders are dispatched within 1-5 business days from our Bengaluru warehouse. Delivery takes 7-8 days to most locations across India.
What is your return and warranty policy?
We offer a 7-day return policy on manufacturing defects only. Contact support within 7 days of receipt for free replacement or full refund. Not applicable for user damage or misuse.
Are bulk discounts available?
Yes, wholesale pricing for orders of 10 or more units. Contact our sales team via WhatsApp or email for a customized bulk quote.
Why Buy from The Engineer Store
- Genuine Products: Sourced directly from authorized distributors with authentication
- Expert Team: Our technical team validates every product before listing
- Fast Shipping: Dispatched within 1-5 days from our Bengaluru warehouse
-
Buy Adafruit 5188 DS3231 Precision RTC - STEMMA QT Online in India
Purchase the Adafruit 5188 DS3231 Precision RTC - STEMMA QT online at The Engineer Store, India's trusted source for genuine electronics. We deliver across Bengaluru, Mumbai, Delhi, Chennai, Hyderabad, Pune, Kolkata, Ahmedabad, Jaipur, and Surat.
Our team in Bengaluru is available 24/7 to support your journey from product selection to project completion.