Are They HATs or pHATs?
For those of you who aren't familiar with Raspberry Pi, HATs and pHATs are the RPi equivalent of Arduino shields; add-on boards for the 40 pin GPIO with the EEPROM designation. HATs and pHATs are essentially the same things but pHATs are designated for smaller models like the RPi Zero, and are often thought of as "partial HATs". If all of this seems confusing, you can just call them HATs and people will know what you're talking about. On a side note, many people in the United Kingdom refer to them as bonnets...
Raspberry Pis Aren't Just for Makers
Raspberry Pis are often dismissed as beginner boards with little use in professional applications, but their ease of use actually makes them a popular choice for prototyping before committing to more specialized components. Raspberry Pis became a lot more appealing to professionals when the Raspberry Pi Foundation designed the Raspberry Pi Zero in 2015. The Pi Zero was such a success that it sold out immediately upon release.
A Raspberry Pi Zero, 5 dollar bill for scale. It also costs $5.
The Raspberry Pi Zero is small and cheap, making it suited for trying out designs that might destroy it in the testing process. Currently, a Raspberry Pi 3 is around $45, whereas an RPi Zero is only $5. Although they don't have as much functionality as a standard RPi, you also aren't paying for the functions that you won't use. Using HATs and modules, you can get the functionality that you're aiming for without breaking the bank.
Below are some HATs that were recently released for Raspberry Pi Zero that add functionality for home automation to the Pi Zero.
Pimoroni Automation HAT
Pimoroni is mostly known for designing fun gizmos for kids and makers, but their automation HAT has a lot of utility. This HAT is compatible with all Raspberry Pis and has relays, analog channels, LED indicators, ADC, and SPI interface. The LED indicators make it a good fit for a Raspberry Pi Zero because it allows you to see what the device is doing without hooking it up to a display. The Pimoroni Automation HAT has a code section on Github to get started with basic functions. You can learn more about its features in the video below.
HATs to Get Your Home Automation Design Online
Most home automation products have internet capability these days. One of the Zero's drawbacks is that it doesn't have connectivity built in. There are, however, a few HATs that can get the Zero online.
It isn't flashy, but the PiJack gives the Zero a much-needed, easy to use internet connection. Since it's a HAT, it connects to the GPIO pins and leaves the Zero's USB port open for other activities. It has LEDs to display connectivity status, allowing your design to function without an interface. It works with the Raspian OS out of the box, so all you need to do is plug in a standard ethernet cable and go!
A tiny Raspberry Pi and its tiny ethernet HAT. Courtesy of PiJack
Red Bear IoT pHAT
With a little extra money and some soldering, you can give your home automation device full IoT connectivity with Bluetooth 4.1 and 2.4 GHz WiFi. Red Bear ran a successful Kickstarter campaign last year and is ready for shipping. You can buy them with or without soldered female headers. If you're ordering in bulk for prototyping, you can get loads of IoT-capable Raspberry Pis for under $15 a piece.
The RedBear IoT pHAT with soldered headers. Courtesy of RedBear
It's good to see prototyping become cheaper and easier as time progresses. With affordable open source hardware and software, active online communities, distributors embracing the maker movement, and crowdfunding platforms, the future looks bright for inventors and small electronics companies.
Are there any Raspberry Pi Zero accessories that you're excited about? Let us know in the comments!