Raspberry Pi display HATs are an easy way to add interaction to your project. Here, we take a look at some options.

Raspberry Pis are useful little computers, employable in a variety of ways. When the HAT specification was announced back in 2014, many companies expanded the Raspberry Pi's flexibility by creating add-ons for the Raspberry Pi 3 B+. The HAT market continues to grow from there. 

Below are 5 Raspberry Pi HATs with integrated displays ranging from LED indicators all the way to touchscreens for headless Pi projects.

Pimoroni Display-O-Tron HAT

The Display-O-Tron is a small 16x3 character LCD display with capacitive touch pads, GPIO breakout pins, and a six-zone RGB backlight. This screen and touchpad combination can come in handy for data logging projects where some user input is needed from time to time. It has many more nifty features along with the ability to interface with other sensors and boards through the selected GPIO pins.

Pimoroni Display-o-tron HAT

Image courtesy of Pimoroni.

Features

  • Fully assembled (apart from optional GPIO header)
  • Slim 16x3 character LCD display
  • Six capacitive touch input buttons
  • Handy six element LED bar graph
  • Six-zone RGB backlight with diffuser
  • GPIO breakout for 5V, 3V3, GND, SDA/SCL, TX/RX, PWM, MOSI/MISO/SCLK/CE1, and GPIO #5, #6, #13, #19, #26
  • Full ASCII set plus eight custom characters

PaPiRus E-Ink HAT

This HAT, successfully funded by a Kickstarter campaign back in 2015, adds an ultra-low power, high-resolution e-paper display to your Pi. However, it is easy to integrate with other microcomputers—even microcontrollers like Arduino. If you need a screen that is easily read in the sun and needs little power for the text, this is the way to go.

The PaPiRus ePaper display HAT

Image courtesy of Pi Supply.

Features

  • Interchangeable screen sizes (1.44", 2.0" or 2.7")
  • 32 MBit Flash Memory
  • Battery Backed Real Time Clock (CR2032 battery included)
  • Easy plug and play operation with onboard EEPROM
  • Digital temperature sensor and thermal watchdog
  • GPIO breakout connector and solder pads
  • Optional reset pin header (for wake on alarm with RTC)
  • 4 x optional slimline switches on top
  • Suitable for 3V or 5V power and logic. Use with RasPi, Arduino, BeagleBone, and more.

The Adafruit PiTFT Plus HAT

The 3.5" display fits onto any Pi with a 2x20 connector and features 480x320 16-bit color pixels along with a resistive touch overlay. 

The plate uses the high-speed SPI interface on the Pi and can also have an HDMI display connected. The display uses the hardware SPI pins (SCK, MOSI, MISO, CE0, CE1) as well as GPIO #25 and #24. GPIO #18 PWM dims the backlight. All other GPIO are broken out into solder pads at the bottom for you to use.

The Adafruit PiTFT Plus HAT

Image courtesy of Adafruit.

Features

  • Fully assembled (apart from optional GPIO header)
  • 480 x 320 resolution
  • Resistive touch
  • Uses Pi’s SPI interface
  • Allows simultaneous HDMI connection
  • GPIO breakout into solder pads
  • Dimmable backlight

The GFX HAT 

The GFX HAT is the bigger, shinier brother of the Display-O-Tron. With it, you can add larger, more complex images to your projects and interact with them using the capacitive touch buttons. Ideal for an IoT project with headless Pis.

the GFX HAT

Image courtesy of Pimoroni.

Features

  • 128 x 64 pixel, 2.15" LCD display
  • Integrated diffuser/reflector assembly
  • Six-zone RGB LED backlight
  • SN3218 LED driver chip (I2C address 0x54)
  • Six capacitive touch buttons with white LEDs
  • Microchip CAP1166 capacitive touch/LED driver chip ((I2C address 0x2c)
  • Comes fully assembled

Unicorn HAT HD

The Unicorn HAT HD is a ready-to-program 16x16 LED matrix, containing 256 RGB LEDs. Because it fits HAT specifications, it is a compact solution for projects needing a multitude of LEDs. The Python library makes it easy to use all of the LEDs,  you can focus on the main parts of your projects.

The Unicorn HD HAT

Image courtesy of Pimoroni.

Features

  • 256 RGB LED pixels in a 16x16 matrix
  • Pixels driven by ARM STM32F and three STP16CPC26 LED drivers
  • Bundled ninja diffuser (which blurs the lines between LEDs) plus nuts and bolts
  • Python library
  • Comes fully assembled

Display HATs Allow Expansion and Interaction

If you’re looking for a way to expand the capabilities of your microprocessor, these displays are a good place to start. After all, if you can’t tell when your scripts are running, how can you be sure they're running at all?

Will you be using any of the HATs we've covered? Have we missed any great ones? Let us know in the comments! 

Eduardo Pecina
Polyglot Programming Pianist :P