Witty Pi 4 Mini - RTC & Power Management for Raspberry Pi

Witty Pi 4 Mini is an add-on board that adds real time clock (RTC) and power management to your Raspberry Pi. It can define your Raspberry Pi’s ON/OFF sequence, and significantly reduce the energy usage. Witty Pi 4 Mini is the fourth generation of Witty Pi and it has these hardware resources onboard:

• Factory calibrated and temperature compensated realtime clock with ±2ppm accuracy.
• Dedicated temperature sensor with 0.125 °C resolution.
• AVR 8-bit microcontroller (MCU) with 8 KB programmable flash.

It is a small electronic board that can add real-time clock and power management to your Raspberry Pi. Witty Pi 4 Mini is a new member of the fourth generation of Witty Pi, and it has bonnet/pHAT form factor.

Please note, our demo photo shows it with a "2x20 Riser Header" which is NOT included!

Witty Pi 4 Mini has a similar design to Witty Pi 4, but it doesn’t come with a DC/DC converter onboard, and uses a super capacitor for RTC time keeping when no power supply is connected. It has solder pads on the back for optional DC/DC converter soldering.

The RTC is factory calibrated and temperature compensated by firmware, achieving ±2ppm accuracy. The time stored in the RTC overwrites the system time on boot, providing accurate time without internet access. You can schedule startup/shutdown and create complex ON/OFF sequences.

Features include:

• Graceful turn on/off Raspberry Pi with a single tap on the switch.
• Full power cut after shutdown to Raspberry Pi and USB peripherals.
• Temperature sensing and accurate RTC.
• Power scheduling and scripting for ON/OFF sequences.
• External voltage monitoring and control.

Supports all Raspberry Pi models with a 40-pin GPIO header, including A+, B+, 2B, Zero, Zero W, 3B, 3B+, 3A+, 4B, and Pi 5.

Uses I2C protocol to communicate with RTC chip PCF85063A, temperature sensor, and microcontroller with adjustable I2C address 0x08 to avoid conflicts.

Software installation instructions:

pi@raspberrypi:~ $ wget http://www.uugear.com/repo/WittyPi4/install.sh
pi@raspberrypi:~ $ sudo sh install.sh

The software and firmware are open-source and available on GitHub.

Technical Details

• Dimensions: 65mm x 30mm x 4mm
• Weight: 9g (net without accessories)
• Microcontroller: ATtiny841
• Realtime Clock: PCF85063A, factory calibrated
• Temperature Sensor: LM75B
• MOSFET Switch: AO4620
• Super Capacitor: 0.07F
• Power In: DC 5V (USB type C or 5V in header P2)
• Output Current: Up to 2.5A for Raspberry Pi and peripherals
• Standby Current: ~0.5mA
• Operating Environment: Temperature -30°C to 80°C, Humidity 0-80% RH no condensing or corrosive gas

User Manual PDF