Knowledge Base
The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.
RTC Pi (Discontinued)
Product Information for the version one RTC Pi board
This article applies to the RTC Pi versions 1.0 to 2.2. For version 3 and later, as well as the RTC Pi Zero, please view the current RTC Pi product page.
The Raspberry Pi is a great low-cost computer with thousands of different uses, but one thing it does not come with is a real-time clock. This means that every time you switch off your Raspberry Pi, it forgets what the time is, and you have to manually set it again the next time you switch your Raspberry Pi on.
The RTC Pi is a battery-backed real-time clock module for the Raspberry Pi. It keeps track of the time while the Raspberry Pi is switched off and allows it to retrieve the current date and time from the RTC Pi when it is switched back on.
The RTC Pi is powered through the host Raspberry Pi using the GPIO port, and extended pins on the GPIO connector allow you to stack the RTC Pi along with other expansion boards. The RTC Pi uses the DS1307 RTC real-time clock and a CR2032 battery to maintain the date and time when the main system power is unavailable.
Unlike most DS1307-based RTC modules, the RTC Pi also includes an I2C logic level converter, allowing you to connect other 5V I2C devices to your Raspberry Pi.
The RTC Pi is pin-compatible with the Raspberry Pi model B+.
We also sell Raspberry Pi A+, B+ and Raspberry Pi 2 versions of this board.
The RTC Pi is beneficial for standalone projects where your Raspberry Pi will not have a network connection and, therefore, no way to retrieve the current date and time from the internet.
A mounting hole is provided to bolt the RTC Pi to your Raspberry Pi securely with our mounting kit (sold separately).
The RTC Pi can also be used on Arduino boards when connected via the I2C bus.
The i2c address for the DS1307 RTC is 0x68. This board is not compatible with the ADC Pi V1 board but is compatible with the Delta Sigma Pi and ADC Pi V2 when alternative i2c addresses are used.
Warning: Do not connect the RTC Pi to your Raspberry Pi when the power is connected without a CR2032 battery installed. This can cause damage to the DS1307 RTC chip.
The RTC Pi uses a CR2032 button battery (battery not included).
Due to shipping restrictions, we can no longer ship the RTC Pi with a battery.
Compatibility Chart
| Model | Compatible |
|---|---|
| Raspberry Pi Model A | Yes |
| Raspberry Pi Model B | Yes |
| Raspberry Pi 1 Model A+ | Yes |
| Raspberry Pi 1 Model B+ | Yes |
| Raspberry Pi 2 Model B | Yes |
| Raspberry Pi 3 Model B/B+ | Yes |
| Raspberry Pi 4 | Yes |
| Raspberry Pi Zero | Yes |
| ODroid C1 | Yes |
| ODroid C2 | Yes |
Schematic
Mechanical Drawings
Click the image to enlarge it.
How to set and read the time
Follow our tutorial on enabling I2C on your Raspberry Pi and set up the real-time clock on the RTC Pi.
Battery Notes: We have had reports that some brands of button cells do not make a reliable connection when fully inserted into the battery holder on the version 1 RTC Pi boards. Moving the battery out by 3-5mm solves this problem.
Sample Code
We have Python libraries available for this expansion board. You can download all of the libraries from GitHub at:
https://github.com/abelectronicsuk/
To download the Python libraries to your Raspberry Pi, type in the terminal:
git clone https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git
Tutorials
RTC Pi and Arduino
RTC Pi and Beaglebone Black
RTC Pi and the Raspberry Pi
Related Expansion Boards
Real-time clock for the Raspberry Pi
