Andrew Tudoroi's Pitanga HAT Gives Your Raspberry Pi a Little Retro LED Love

Maker Andrew Tudoroi has designed a Hardware Attached on Top (HAT) accessory for Raspberry Pi and compatible single-board computers that delivers a display for those who like a retro aesthetic — thanks to a choice of retro-style LED matrices on its top.

"I’ve always been drawn to retro LED displays. While exploring Raspberry Pi extension HATs, I came across Pimoroni's micro-LED board. I was immediately hooked and decided I needed one," Tudoroi explains of his inspiration. "Unfortunately, I wasn’t able to get my hands on it. This setback inspired me to try my hand at PCB design, making this project my very first — from initial design all the way to ordering PCBs from well-known manufacturers."

The resulting board, dubbed the Pitanga HAT, is based around the popular HT16K33 memory-mapping LCD driver chip. Tudoroi's initial design, created in KiCad, included four push-button switches in addition to six 5×7 replica vintage LED matrix chips — plus a footprint for an STMicroelectronics microcontroller for optional standalone use, which was never fitted.

A design flaw in the power input of the original model led to a redesign and the inclusion of a level converter for more reliable operation. At the same time, Tudoroi added a fifth push-button switch and two I2C ports — creating what he describes as "a polished Pitanga HAT" with more flexibility.

"A completely separate and fascinating journey was finding compatible LED displays for this design," Tudoroi adds, listing the LTP-305R, LTP-305G, ALS340A, ALS340A1, 3LS340, 3LS363, AL104, Texas Instruments TIL-305, Lite-On LTP-305, DIALCO 745-0005, IEE LR1704R, and Mosanto MAN 2 as tested and working. "These displays are replicas of replicas of replicas of the original models, yet they retain their retro charm and work beautifully with the project."

More details are available on Hackaday.io, while Tudoroi has released hardware design files on GitHub under an unspecified open source license; the supporting software is available in a separate repository.