WITTY PI 3: REALTIME CLOCK AND POWER MANAGEMENT FOR RASPBERRY PI
WITTY PI 3: REALTIME CLOCK AND POWER MANAGEMENT
DESIGNED ESPECIALLY FOR RASPBERRY PI
Witty Pi 3 is the third generation of Witty Pi, and it is the descendant of Witty Pi 2. It adds realtime clock (RTC) and power management to your Raspberry Pi, and can define complex ON/OFF sequence with simple script. Witty Pi 3 supports all Raspberry Pi models with 40-pin header, including A+, B+, 2B, Zero, Zero W, 3B, 3B+, 3A+ and 4B.
You just need to run these two commands in your Raspberry Pi to install Witty Pi 3’s software:
Then you mount Witty Pi 3 on your Raspberry Pi, and enjoy these amazing features provided by Witty Pi 3:
- You can power your Raspberry Pi with higher voltage.
- You can gracefully turn on/off Raspberry Pi with single tap on the switch.
- After shutdown, Raspberry Pi and all its USB peripherals’ power are fully cut.
- Raspberry Pi knows the correct time, even without accessing the Internet.
- Raspberry Pi knows the temperature thanks to the sensor in RTC chip.
- You can schedule the startup/shutdown of your Raspberry Pi.
- You can even write a script to define complex ON/OFF sequence.
- Shutdown Raspberry Pi when input voltage is lower than pre-set value.
- Turn on Raspberry Pi when input voltage raise to pre-set value.
- When the OS loses response, you can long hold the switch to force power cut.
Comparing to Witty Pi 2, Witty Pi 3 uses the same RTC chip (DS3231SN) and introduces a new micro-controller (ATtiny841), which allows it to behave smarter and handle more complex situations. Thanks to the new on-board LDO voltage regulator (LM29150), Witty Pi 3 can accept DC voltage higher than 5V (up to 26V, depends on the load and heat sink).
Witty Pi 3 doesn’t have any jumper, and all configurations are done via I2C interface. Witty Pi’s software can help you to make configuration very quickly.
You can find much more information in its user manual: http://www.uugear.com/doc/WittyPi3_UserManual.pdf
Each Witty Pi 3 package contains:
- Witty Pi 3 board x 1
- CR2032 battery x 1
- M2.5 x 11mm Copper Standoff x 4
- M2.5 screws x 8
Dimension: 65mm x 56mm x 19mm
Weight: 20g (net weight without battery)
Battery: CR2032 (for time and alarms keeping)
Power In: DC 5V (via micro USB) or DC 5.3V~26V (via XH2.54 connector, better no higher than 8V without additional heat sink)
Output Current: Up to 3A for Raspberry Pi and its peripherals if input via micro USB port. Up to 2A if input via XH2.54 connector.
Static Current: ~1mA
Operating Temperature: -30℃~80℃ (-22°F~176°F)
Storage Temperature: -40℃~85℃ (-40°F~185°F)
Humidity: 0~80%RH, no condensing
The Software for Witty Pi 3 is written with BASH (Unix shell).
The source code is public on Github: https://github.com/uugear/Witty-Pi-3
To install the software, just run these two commands:
After the installation is done, reboot your Raspberry Pi.
To launch the Witty Pi utility, just run these commands:
More details about software installation and usage could be found on the user manual.
CONFLICTION WITH 1-WIRE INTERFACE
If you have 1-Wire interface enabled and didn’t specify the GPIO pin for 1-Wire, it will use GPIO-4 and that conflict with Witty Pi. Witty Pi uses GPIO-4 to receive shutdown command, if GPIO-4 is also assigned to 1-Wire, Witty Pi’s software will receive shutdown command unexpectedly. If your Raspberry Pi always automatically shutdown itself after installing Witty Pi’s software, that most probably due to the confliction with 1-Wire interface.
When this happens, you most probably can not login your Raspberry Pi because it always shuts itself down before you get the chance to login. To solve this problem, you will need to take out the micro-SD card on your Raspberry Pi, and access its file system via a card reader. You need to edit the config.txt file in the “boot” volume to change the GPIO pin used by 1-Wire interface, or you can disable 1-Wire interface if you don’t need it for now. You need to find something like “dtoverlay=w1-gpio” in the file.
If you want 1-Wire to use GPIO-18, just change “dtoverlay=w1-gpio” to:
If you want to disable 1-Wire interface, just comment it out:
Save the file and eject your micro SD card, and put it back to your Raspberry Pi. Now your Raspberry Pi should be able to boot normally.
SCHEDULE SCRIPT GENERATOR
You can now use our web app to create and debug the schedule script for Witty Pi.
If you want, you can place Witty Pi 3 and Raspberry Pi into an Acrylic case: