All posts tagged switch

New Product: Witty Pi 4 Mini

After we announced Witty Pi 4, there is no surprise that Witty Pi 4 Mini is also on its way. Today is the day, and we now announce our new product Witty Pi 4 Mini.

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.

What’s New?

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.


New Revision of Witty Pi 3!

Today we are proud to announce Witty Pi 3 Rev2: a new revision of Witty Pi 3. This new revision changes the 5V input connecter from micro USB to USB type C, and replaces the onboard linear regulator (LM29150) with switching DC/DC converter (MP4462). These changes give Witty Pi 3 much better ability to output higher current, and also practically widen the range of input voltage.

What’s New?

The appearance of Witty Pi 3 Rev2 is very similar to the first revision (please see the picture below). The locations of headers and switch remain the same, that means the new revision and old revision are physically interchangeable (except that you need to use type C plug instead of micro USB plug, if you want to give it 5V).

To type C connector and the new DC/DC converter is at up-right corner of the board. The table below compares the two revisions with detailed parameters.

Because the first revision uses linear regulator (LM29150), its efficiency drops very quick when the input voltage increase. That means using it on 12V or 24V system is not practical: even if the regulator can work with extra heat sink, the efficiency will be so poor and that ruins the advantage of using Witty Pi, which is saving energy in most cases. Now the new revision comes with a decent switching DC/DC converter, which can work up to DC 28V without adding extra heat sink, and still keeps the efficiency above 80%, that is indeed a comprehensive improvement.

Firmware and Software Update

Witty Pi 3 Rev2 comes with newer version of firmware (V1.03, with ID=0x23). This firmware allows setting the power cut delay to a bigger value (up to 25.0 seconds). The purpose for this update is to workaround the boot delay caused by USB boot or NOOBS. More details can be found in its user manual.
The software is also updated to V3.12, to allow users to actually set a longer power cut delay. Also the we made some improvements on Internet time synchronisation, to avoid writing incorrect time into system, when the network is not stable.
UUGear Web Interface (UWI) is also updated to V1.01, to support the new revision of Witty Pi 3. When you install the new software, it will install the latest UWI for you (given you don’t have “uwi” folder in your home directory).
Please notice the firmware and software update are not dedicated for Witty Pi 3 Rev2. Witty Pi 3 (Rev1) and Witty Pi 3 Mini can also use the new firmware and software. However you will need to upgrade the firmware by yourself.

Price and Where to Buy?

Witty Pi 3 Rev2’s retail price is 570 CZK (about 22.01EUR  /  19.30GBP  /  26.40USD).
You can order it from our e-shop or you may be able to order it from our resellers soon.

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