Description
Two of the biggest challenges with the Raspberry Pi in portable/mobile/automotive applications is the lack of an accurate way to keep time and a flexible input DC power supply. This Raspberry Pi Power / RTC HAT solves this problem! Onboard is a fused and reverse polarity protected DC input coupled to a beefy 3A 5V DC/DC converter. Connected to a 12V automotive battery, this board is happy running the Piunder heavy load all day long.
Since a battery powered Pi is not likely going to have reliable access to the internet to keep time we have also added a nice, temperature compensated, DS3231 chipset by Maxim. The chip is connected directly to the I2C bus and uses address 0x68. Simply add a CR1220 battery to the holder onboard, set the time, and it will keep it within ±0.432 Second/Day (roughly ±2 minutes a year) in temperatures ranging between -45°C and +85°C.
Even with the above features, there was still quite a bit of room left over. The remainder of the board has been left as open prototype space with slightly larger than standard plated through holes. These should fit just about any breadboard pitch components!
A stacking header is not included ā we recommend looking at the Raspberry Pi GPIO header ā this keeps everything nice and low profile!
Features
- RTC Accuracy of ±0.432 Second/Day
- Two Time-of-Day Alarms
- RTC Battery Backup: CR1220
- 5V 3A Output to power Raspberry Pi
- Dimensions: 65 x 56mm
- Leap-Year Compensation Up to Year 2100
- Complete Clock Calendar Functionality
- Maximum Regulator Input: 36VDC
- Recommended Input: 7 – 16VDC
- Height: 12mm
Resources
Tutorials:
Adding an RTC to the Raspberry Pi: https://learn.adafruit.com/adding-a-real-time-clock-to-raspberry-pi/set-up-and-test-i2c
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Warranty Policy
This product has a 30 Day Warranty from the date of delivery. The item must not be modified, abused, incorrectly hooked up, or used for purposes outside the original scope of design.
Return Policy
This product is returnable Within 14 Days of delivery for a store credit. Item must be unopened, unused, and in re-saleable condition.
Denis Cheong (verified owner) –
You should include a voltage divider on the board so that there is an input voltage sense back into the raspberry pi, it would be very useful.
Chris @ BCR –
Hi Denis,
Thanks for the feedback! Would be a useful (and easy) addition to the board. We also have a third version of this board in development that might be of interest – it features input voltage sense by way of analog to digital converter. It is primarily designed around allowing a Pi to maintain the charge on its own 12V lead acid battery backup, but could be adapted to a variety of other applications.
Urs (verified owner) –
Do I need to install any software to run the board?
Front Desk @ BCR –
Hi Urs,
No specific software is required – however, if you want to pull the system time from the RTC a few commands do need to be run to enable it. There is a tutorial coming in a few weeks centered around using Raspbian Buster – let us know if you have any additional questions!
Urs (verified owner) –
This is perfect – I am waiting for your tutorial then!
Nato –
There’s one thing I’m not crystal clear on: would this board allow the Raspberry Pi to power on from a powered-off state at, for example, a pre-programmed time each day?
Chris @ BCR –
This board does not have that sort of capability – you would require some sort of external microcontroller to act as the watchdog. Let us know if you have any further questions!
Mike Inman –
Very cool, I’m looking for a similar board in a PiZeroW form factor…