Witty Pi 3 Rev2

The Witty Pi 3 Rev2 is the latest generation of the Witty Pi 3!

This new revision changes the 5V input connecter from micro-USB to USB-C, and replaces the onboard linear regulator (LM29150) with switching DC/DC converter (MP4462). These changes give the Witty Pi 3 a much better ability to output a higher level of current (3A) and also widen the range of input voltage (up to DC 28V).

The Witty Pi 3 adds a real-time clock (RTC) and power management to your Raspberry Pi, and can define complex ON/OFF sequences with a simple script. The board supports all Raspberry Pi models with 40-pin header.

Features

• Power your Raspberry Pi with higher voltage (up to DC 28V)
• Gracefully turn on/off Raspberry Pi with a single tap on the button
• Fully cut the power of Raspberry Pi and all its USB peripherals after shutdown
• Automatically synchronise time between the real-time clock and Raspberry Pi
• Monitor the temperature around your Pi (thanks to the sensor in the RTC chip)
• Schedule the startup/shutdown of your Raspberry Pi
• Write a script to define complex ON/OFF sequence
• Shutdown Raspberry Pi when the input voltage is lower than the threshold value
• Turn on Raspberry Pi when input voltage raise over the threshold value
• Long hold the button to force power cut (when the OS loses response)

Witty Pi 3 Rev2 uses a DS3231SN as the real-time clock and ATtiny841 as the micro-controller. Thanks to the on-board DC/DC converter (MP4462), the Witty Pi 3 Rev 2 can accept input voltages up to 28V.

You can find much more information in the user manual.

Installation

Installation is easy - just run these two commands in your Raspberry Pi to install Witty Pi 3’s software:

• wget http://www.uugear.com/repo/WittyPi3/install.sh
• sudo sh install.sh

Then mount the Witty Pi 3 Rev2 on your Raspberry Pi and build your next project!

Update 17/03/21: UUGear have discovered a bug in the V1.03, ID=0x23 firmware which may cause the device to lose response after being woken up by a startup alarm. A new version of the firmware (V1.04, ID=0x24) resolves this issue. The following document describes how to check your version and update if necessary.

Package Contents

Each Witty Pi 3 Rev2 package contains:

• 1x Witty Pi 3 Rev2 board
• 1x CR2032 battery
• 4x M2.5 x 11mm Copper Standoff
• 8x M2.5 screws

Specification

• Dimensions: 65mm x 56mm x 19mm
• Weight: 23g (net weight without battery)
• Battery: CR2032 (for time and alarm keeping)
• Power In: DC 5V (via USB type C connector) or DC 6V~28V (via XH2.54 connector)
• Output Current: Up to 3A for Raspberry Pi and its peripherals
• 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

Resources

• User manual

Software

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:

• wget http://www.uugear.com/repo/WittyPi3/install.sh
• sudo sh install.sh

After installation is complete, reboot your Raspberry Pi.

To launch the Witty Pi utility, just run these commands:

• cd wittypi
• ~/wittypi $ ./wittyPi.sh

More details about software installation and usage can be found in the user manual.

Conflict 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 commands, if GPIO-4 is also assigned to 1-Wire, Witty Pi’s software will receive shutdown commands 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 log in to your Raspberry Pi because it always shuts itself down before you get the chance to log in. 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:

• dtoverlay=w1-gpio,gpiopin=18

If you want to disable 1-Wire interface, just comment it out:

• #dtoverlay=w1-gpio

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 the UUGear web app to create and debug the schedule script for Witty Pi.