Witty Pi 4 Mini has same shape factor as Witty Pi 3 Mini, and the connector locations are not changed. This make Witty Pi 4 Mini and Witty Pi 3 Mini physically exchangeable.
Comparing to Witty Pi 3 Mini, Witty Pi 4 Mini uses USB type-C connector instead of micro USB connector, and it has another unpopulated 7-pin header in the middle of the board.
Comparing to the full-sized Witty Pi 4, Witty Pi 4 Mini uses super capacitor instead of CR2032 battery for off-power time keeping. Witty Pi 4 Mini doesn’t come with an on-board DC/DC converter.
Similar to the full-sized Witty Pi 4, Witty Pi 4 Mini also uses the “single I2C device” design. Instead of exposing the realtime clock and temperature sensor directly to Raspberry Pi, it uses micro-controller (MCU) to emulate one I2C device (with address 0x08), and only exposes this I2C device to Raspberry Pi. On the other hand, it implement its internal I2C bus to communicate with the realtime clock and temperature sensor.
Witty Pi 4 Mini’s firmware is basically the same with the one in Witty Pi 4 Mini, except that it has a different firmware ID. Just like Witty Pi 4, Witty Pi 4 Mini’s firmware also maps all I2C registers in realtime clock and temperature sensor into its own I2C device, and you can access all I2C registers in realtime clock and temperature sensor via single I2C device.
Since the address of the single I2C device is configurable, you can always avoid the I2C address conflicting.
Same as full-sized Witty Pi 4, Witty Pi 4 Mini can also turn your Raspberry Pi into a temperature controlled device. You can put it into sleep when temperature is rather high, or the other way around.
Migrate from Witty Pi 3 Mini to Witty Pi 4 Mini
If you are using Witty Pi 3 Mini in your project, you may want to know more details about the the difference between Witty Pi 3 Mini and Witty Pi 4 Mini. In the user manual, you can find a chapter (chapter 13) about how to migrate from Witty Pi 3 Mini to Witty Pi 4 Mini.
How about Witty Pi 3 Mini?
Witty Pi 3 Mini is discontinued. We unfortunately do not offer the possibility to continue producing Witty Pi 3 Mini, due to the shortage of DS3231SN chip.
We will do our best to help our customers to migrate from Witty Pi 3 Mini to Witty Pi 4 Mini.
Price and Where to Buy?
Witty Pi 4 Mini ’s retail price is 18.00 EUR (about 15.32GBP / 18.42USD / 23.74CAD), and you can order it here.
You may be able to order them from our distributors soon.