Witty Pi 4 Mini: RTC Relógio de Tempo Real e Gestor de Energia para Raspberry Pi

Witty Pi 4 Mini is an uHAT shaped add-on board that adds realtime clock 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.

Witty Pi 4 Mini has very similar design with Witty Pi 4, however it doesn’t come with a DC/DC converter onboard, and it uses super capacitor for RTC time keeping when no power supply is connected. Witty Pi 4 Mini has solder pads on the back, which allow you to solder a DC/DC converter (LDO or switching DC/DC converter) there.

Remarks: Witty Pi’s software is developed and tested under Raspberry Pi OS (the former Raspbian). If you want to use Witty Pi on other Linux distributions, you may not be able to install the software without error. This is due to the fact that different Linux distributions have different packages installed by default, and their default users may have different privilege settings too. You may need to modify the software installation script or even the software itself, however this will need you to have some knowledge of BASH programming.

Accurate Realtime Clock and ON/OFF Scheduling

The realtime clock (RTC) on Witty Pi 4 Mini has been calibrated in the factory and Witty Pi 4 Mini’s firmware also makes temperature compensation for the crystal. This makes the RTC very accurate and the actual annual error is limited within ±2ppm. When your Raspberry Pi boots up, the time stored in the RTC will overwrite the system time. As a result, your Raspberry Pi knows the correct time even without accessing the Internet. You can schedule the startup and/or shutdown of your Raspberry Pi, and make it a time-controlled device. You can even define a schedule script to schedule complicated ON/OFF sequence for your Raspberry Pi.

Scheduling the ON/OFF sequence for Raspberry Pi is the most popular feature of Witty Pi, and it is extremely useful for systems that powered by battery. By only turning on Raspberry Pi when necessary, the battery can be used way much longer with Witty Pi installed.

Temperature Controlled Device

The temperature sensor on Witty Pi 4 Mini has 0.125 °C resolution. The temperature data is used for compensating the crystal and make the RTC more accurate.

You can also specific the action (startup or shutdown) when temperature goes above or below the preset threshold. Which means you can also make your Raspberry Pi a temperature-controlled device.

Note: For more detailed information, please check this page.