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Back-up Power, Energy Harvesting & RTCs for Raspberry Pi

December 17, 2018 by Paul Shepard

Add a real-time clock to Raspberry Pi with Witty Pi 2 (pictured above) from UUGear s.r.o. or with PiJuice from Pi Supply. Witty Pi 2 also enables users to define complex ON/OFF sequence with simple script.  PiJuice features an onboard 1820-mAh Li-ion battery for 4 to 6 hours of back-up power for a Raspberery Pi board in constant use (with support for larger Lipo Battery of 5000- or 10,000-mAH+ to last up to 24+ hrs).

Witty Pi 2 is the new generation of Witty Pi, which adds RTC and power management to Raspberry Pi, and can define complex ON/OFF sequence with simple script. Witty Pi 2 supports all Raspberry Pi models with 40-pin header, including A+, B+, 2B, Zero and 3B.

Comparing to the old Witty Pi, Witty Pi 2 uses much better RTC chip (DS3231SN), which only has <160 seconds error per year. Also this RTC chip has temperature sensor built-in, so you can read the temperature around your Raspberry Pi via the software. The new "dummy load" feature is very useful when you use power bank as power supply, it will draw peak current with certain interval, and keep your power bank alive.

After installing the software on your Raspberry Pi, you can enjoy these new features:

  • Single tap on the button to gracefully turn on/off Raspberry Pi.
  • After shutdown, the power for Raspberry Pi and all its USB peripherals are fully cut.
  • Raspberry Pi knows the correct time, even without accessing the Internet.
  • You can schedule the startup/shutdown of your Raspberry Pi.
  • You can even write a script to define complex ON/OFF sequence.

Taking Raspberry Pi Off the Grid

PiJuice can take your Pi off the grid. The real time clock (RTC) on board will let your Pi know what time it is even with no power input or internet connection. Alongside this is an integrated microcontroller (MCU) chip which will manage soft shut down functionality and a true low power deep sleep state and intelligent startup.

You will be able to always keep track of the charge levels and other info with the two built-in tri-colored RGB LEDs, trigger events and scripts with the three programmable buttons and since the PiJuice will use up to just five of your GPIO pins (just power and I2C), the rest are free to diversify your project. The stacking header allows you to continue to use your existing HATs and add-ons with PiJuice.

Energy Harvesting Power for Raspberry Pi

Ultimate integrated power is one thing but what if we could make the Raspberry Pi renewably powered too? Solar, wind, thermoelectric and other renewable power is free, clean, and green and we're proud to have developed an affordable and efficient renewable power solution for the Raspberry Pi! PiJuice is self-monitoring and, like a space satellite, can become a completely autonomous system.

Use the PiJuice as part of an autonomous camera system, weather stations, off-grid desktops, and so many other great outdoor projects. View and buy the PiJuice solar panels separately here.