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July 20, 2022

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.

 

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June 8, 2022

New Product: Witty Pi 4

Today we are very proud to announce our new product: Witty Pi 4!

This is the 4th generation of Witty Pi. Comparing with Witty Pi 3, it has same shape factor and same connector locations, and have some interesting new features.

Witty Pi 4

What’s New?

Witty Pi 4 uses a new structure to organise its hardware resources. 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 and connect the realtime clock and temperature sensor to that internal I2C bus.

Witty Pi’s firmware also maps all I2C registers in realtime clock and temperature sensor into its own I2C device, so you can access all I2C registers in realtime clock and temperature sensor via single I2C device.

Because the address of this single I2C device is also configurable, you can always avoid the I2C address conflicting.

A new feature of Witty Pi 4 is to 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.

In Witty Pi 3, you cannot specify the “seconds” in scheduled shutdown time, and that was due to the limitation from the realtime clock hardware. In Witty Pi 4, the alarms for startup and shutdown are implemented by the firmware, and hence you can specify the “seconds” in both scheduled times.

There are other differences between Witty Pi 3 and 4, and you can find a chapter about how to migrate from Witty Pi 3 to Witty Pi 4 in the user manual (chapter 13).

How about Witty Pi 3?

Witty Pi 3 is discontinued. We understand it is not good for ongoing projects who use Witty Pi 3, and we wanted to continue producing Witty Pi 3 for a while. Unfortunately due to the shortage of DS3231SN chip, we can not do so and have to discontinue Witty Pi 3.

We will do our best to help our customers to migrate from Witty Pi 3 to Witty Pi 4.

Price and Where to Buy?

Witty Pi 4’s retail price is 25.00 EUR (about 21.48GBP / 29.80USD / 36.77CAD), and you can order it here.

You may be able to order them from our distributors soon.

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June 14, 2017

New Revision of Witty Pi 2

Witty Pi 2 is a HAT-shaped add-on for Raspberry Pi that adds accurate realtime clock (DS3231SN) and power management, which allows you to define complex ON/OFF sequence of your Raspberry Pi with simple script. Witty Pi 2 is one of our flagship product and is becoming more and more popular recently. Today we announce the second revision of Witty Pi 2, which only has slight difference on the look and introduces a small enhancement, yet significantly simplifies our assembly process.
The figure below shows the different look of reversion 1 and reversion 2:
rev1_vs_rev2
Until recent days, both Witty Pi and Witty Pi 2 use a rather complex assembly process. The 40-pin stackable header needs to be soldered manually on the board first, and then a plastic pin holder will be pressed on the board, to make the board look nicer.
40_pin_header_assembly
Soldering the 40-pin stackable header is a huge workload, and we could hardly bear it, as the demand of Witty Pi 2 goes higher. So we take the idea from the Sense HAT, and use a surface-mounted female header to assembly the stackable header.

smd_header

Witty Pi 2 (reversion 2)


 
This SMD female header is customised, and has only 2mm plastic height (the one on Sense HAT has 3.5mm plastic height). This slim header can make sure the stackable header be hold firmly, and still has enough length of pin exposed on top. This female header increases the BOM cost, but it saves us a lot of time on soldering the stackable header.
Although the stackable header is fixed in place, you can still take it away if you wish. By doing so your Witty Pi 2 becomes a very slim board and more suitable for portable project. For example, you can connect it with Raspberry Pi Zero:
with_rpi_zero
In reversion 2, we also made a small enhancement on the design, and prolong the delay time (for 2~4 seconds) before Witty Pi 2 cuts the power. The purpose of this enhancement is to avoid “hard shutdown” unintentionally. This change doesn’t make Witty Pi 2 more NOOBS friendly, since the delay on NOOBS menu is way longer. You will still need to avoid using NOOBS, or disable the NOOBS menu to make Witty Pi 2 work. More details about this issue can be found on page 5 of Witty Pi 2 user manual.
The second revision of Witty Pi 2 is now in stock, and the pricing is the same with the first revision.

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