Page 59 - Raspberry Pi as a Foundation for Boosting Computer and Technology Literacy

Miscellaneous HATs 4.4
a Raspberry Pi camera and a Compute Module 4), or Techbase ClusBer-
ry 9500-CM4 (an industrial Raspberry Pi Compute Module 4 cluster).
On 19 October, 2020, Jeff Geerling tested the new Raspberry Pi
Compute Module 4. His thorough review can be found here:  The
Raspberry Pi Compute Module 4 Review. Raspberry Pi Compute Mod-
ule 4 was featured in The MagPi, issue 99 (Raspberry Pi 2020).

4.4 Miscellaneous HATs 4.4
Raspberry Pi is an excellent platform for many projects. Having the
right expansion board for a project is a prerequisite for any project
you may think of building. In 2014, the HAT standard was introduced
to connect HATs to the Raspberry Pi’s 40-pin GPIO (btw, for Arduino,
HATs are called ‘shields’). HATs can be stacked, so you can put a HAT
on top of a HAT and often share the same pins of a GPIO underneath.
Many HATs on the market come with a Python module and are us-
er-friendly, and many come with documentation and online resources.
Let us have a look at some HATs. We have already mentioned the Rasp-
berry Pi HAT for Lego projects, which is relatively cheap at 25 euros,
works with all Raspberry Pis, and is certainly a good way to start play-
ing with your child. Another cost-effective and useful HAT is Pimoroni
IO Expander (10 euros), which adds an extra 14 GPIO pins. If you are
keen on retro gaming, Pimoroni X HAT provides everything one needs
for an arcade build and provides power to the Raspberry Pi. It is a good
idea to use a GPIO pin extension stacker and a fan or heat sink for the
Raspberry Pi, because gaming puts a load on the processor and as the
board covers the CPU, Raspberry Pi can become very warm.
Pimoroni Breakout Garden is a HAT that enables multiple sensors to
be connected through I2C. There are six slots, two SPI slots for break-
outs (e.g. an LCD breakout), and four I2C slots, each with its own ad-
dress so that different devices can be used at the same time. The Gar-
den HAT comes with standoffs for easy installation on the Raspberry
Pi and is recommended for science projects of all types.
Google AIY Voice kit with HAT may be the best HAT for building AI
projects. Google assistant will help you find answers to some questions
you might have after the project is finished, even if Raspberry Pi Zero
or Zero W was your chosen small computer.
Automation HAT from Pimoroni is a monitoring and automation
HAT that also belongs to the list of must-haves. So too is Pimoroni
Unicorn, which is a HAT with a 64 LED (or 256 LED in an HD model)

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