Witty Pi 4 HAT - RTC & Power Management for Raspberry Pi
Quantity Discounts:
- 6-12 $84.70 (exc GST)
- 12+ $82.05 (exc GST)
Out of Stock
Sign up to get notified when it's available to order.
Restrictions apply to this equipment as it uses button/coin cell batteries:
- The equipment is intended to be used in trades, professions or industries
- The equipment is not intended for sale to the general public
- The equipment is not intended to be used where children are present
- You are aware that this equipment may not meet child safety testing requirements as it is not intended to be used by consumers or general public, but rather, is intended to be used in trades, professions or industries in conjunction with the limitations and restrictions listed above
- You are aware that these restrictions are due to a change in Australian legislation in 2022 for button/coin cell batteries
A declaration of use will need to be submitted during checkout.
Witty Pi 4 is an add-on board that adds real-time clock and power management to your Raspberry Pi. It can define your Raspberry Pi’s ON/OFF sequence and significantly reduce energy usage. Witty Pi 4 is the fourth generation of Witty Pi, and it has these hardware resources onboard:
- Factory calibrated and temperature compensated real-time clock with ±2ppm accuracy.
- Dedicated temperature sensor with 0.125 °C resolution.
- On-board DC/DC converter that accepts up to 30V DC.
- AVR 8-bit microcontroller (MCU) with 8 KB programmable flash.
Note: 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 REAL TIME CLOCK AND ON/OFF SCHEDULING
The real time clock (RTC) on Witty Pi 4 has been calibrated in the factory, and Witty Pi 4’s firmware also makes temperature compensation for the crystal. This makes the RTC very accurate, and the actual annual error is limited to ±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 scheduled script to schedule a 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 battery-powered systems. 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 has 0.125 °C resolution. The temperature data is used for compensating the crystal and makes the RTC more accurate.
You can also specify the action (startup or shutdown) when the temperature goes above or below the preset threshold. This means you can also make your Raspberry Pi a temperature-controlled device!
DC/DC CONVERTER AND E-LATCHING POWER SWITCH
Witty Pi 4 comes with a DC/DC converter on board, which allows you to power your device with 6~30V power supply. You can also power your device with 5V via the USB type C connector.
Witty Pi 4 also implements an e-Latching power switch, which is very similar to the power switch on your PC/Laptop computer. You can gracefully turn on/off your Raspberry Pi with a single tap on the button. The software running in the background will execute the shutdown command before the power gets cut; this avoids the data corruption caused by a hard shutdown.
Witty Pi 4 supports all Raspberry Pi models that have the 40-pin GPIO header, including A+, B+, 2B, Zero, Zero W, Zero 2 W, 3B, 3B+, 3A+, and 4B. You will need to solder the 40-pin header to Zero/Zero W/Zero 2 W model beforehand, so they can make a reliable connection with Witty Pi.
SINGLE I2C DEVICE
Witty Pi 4 uses MCU to emulate a single I2C device with default address 0x08 and also map all I2C registers in real time clock and temperature sensor as virtual I2C registers in the same device. You can access all I2C registers in real time clock and temperature sensor via the single I2C device emulated by Witty Pi 4.
The advantage of this new design is that Witty Pi 4 hides other I2C devices (real time clock, temperature sensor) and becomes the proxy of them to talk to Raspberry Pi. Because the I2C address used by Witty Pi 4 can be changed to any value, you can always avoid the I2C address conflicting.
UWI SUPPORT
Witty Pi 4 is fully supported by UWI (UUGear Web Interface), and you can access your Witty Pi 4 on any device that has network access.
SOFTWARE INSTALLATION:
You just need to run these two commands in your Raspberry Pi to install Witty Pi 4’s software:
pi@raspberrypi:~ $ wget https://www.uugear.com/repo/WittyPi4/install.shpi@raspberrypi:~ $ sudo sh install.sh
The software and firmware of Witty Pi 4 are open-sourced. You can find the source code on GitHub.
Each Witty Pi 4 package contains:
- Witty Pi 4 board x 1
- 30cm 22AWG XH 2.54 cable x 1
- M2.5 x 11mm Copper Standoff x 4
- M2.5 screws x 8
Note: Coin cell battery is not included, to make shipping a lot easier for folks abroad. You can get one locally or add one from the Adafruit shop if you need.
Technical Details
Specifications:
| Dimension | 65mm x 56mm x 19mm |
| Weight | 23g (net weight without accessories) |
| Microcontroller | ATtiny841 (datasheet) |
| Realtime Clock | PCF85063A (datasheet), calibrated in factory. |
| Temperature Sensor | LM75B (datasheet) |
| DC/DC Converter | MP4462 (datasheet) |
| MOSFET Switch | AO4616 (datasheet) |
| Battery | CR2032 (for time keeping when power supply is disconnected) |
| Power In | DC 5V (via USB type C connector)or DC 6V~30V (via XH2.54 connector) |
| Output Current | Up to 3A for Raspberry Pi and its peripherals |
| Standby Current | ~0.5mA |
| Operating Environment | Temperature -30°C~80°C (-22°F~176°F)Humidity 0~80%RH, no condensing, no corrosive gas |
Exact shipping can be calculated on the view cart page (no login required).
Products that weigh more than 0.5 KG may cost more than what's shown (for example, test equipment, machines, >500mL liquids, etc).
We deliver Australia-wide with these options (depends on the final destination - you can get a quote on the view cart page):
- $3+ for Stamped Mail (typically 10+ business days, not tracked, only available on selected small items)
- $6+ for Standard Post (typically 6+ business days, tracked)
- $10+ for Express Post (typically 2+ business days, tracked)
- Pickup - Free! Only available to customers who live in the Newcastle region (must order online and only pickup after we email to notify you the order is ready). Orders placed after 2PM may not be ready until the following business day.
Non-metro addresses in WA, NT, SA & TAS can take 2+ days in addition to the above information.
Some batteries (such as LiPo) can't be shipped by Air. During checkout, Express Post and International Methods will not be an option if you have that type of battery in your shopping cart.
International Orders - the following rates are for New Zealand and will vary for other countries:
- $11+ for Pack and Track (3+ days, tracked)
- $16+ for Express International (2-5 days, tracked)
If you order lots of gear, the postage amount will increase based on the weight of your order.
Our physical address (here's a PDF which includes other key business details):
Unit 18, 132 Garden Grove Parade
Adamstown
NSW, 2289
Australia
Take a look at our customer service page if you have other questions such as "do we do purchase orders" (yes!) or "are prices GST inclusive" (yes they are!). We're here to help - get in touch with us to talk shop.
Have a product question? We're here to help!
Videos
View AllGuides
Raspberry Pi 5 Vs Raspberry Pi 4 Model B | Comparison & Benchmarking
Raspberry Pi 5 | Review, Performance & Benchmarks
Upgrade your Project for the Raspberry Pi 4
Raspberry Pi 4 vs Raspberry Pi 3 Plus (Model B)
Projects
safePower
ESP32 IR-Triggered Camera with Home Assistant Integration
LuMa 1 - The Neo Disco Ball
Educational Workshops
Raspberry Pi Workshop for Beginners
Makers love reviews as much as you do, please follow this link to review the products you have purchased.
Product Comments