Andrew Tudoroi's RPI TinyNumberHat Uses Retro Displays to Put Big Numbers on Your Raspberry Pi
Based around the AL304 and ALS314 seven-segment display families, this compact board includes four button inputs and nine digits.
Self-described electronics and software enthusiast Andrew Tudoroi has built an add-on for the Raspberry Pi family of single-board computers and compatibles that adds a teeny-tiny display for conversely large numbers: the RPI TinyNumberHat.
"While flipping and scrolling through old encyclopedias and magazines, I stumbled upon some amazing golden boys of display technology: the AL304 and ALS314 7-segment and dot displays," Tudoroi explains. "They look super cool and the gold is real! Back in the day, that gold was a giveaway, a sign of something truly special. Inspired by these vintage components, I knew I had to build something with them."
That something turned out to the RPI TinyNumberHat, a Hardware Attached on Top (HAT) accessory for any Raspberry Pi or compatible single-board computer with 40-pin general-purpose input/output (GPIO) header — though designed to mimic the footprint of the smallest Raspberry Pi Zero family. The board hosts nine of the compact ALS314 numerical displays — with a second variant using AL304V, which glow in a lime-green color to the ALS314's red — along with a Holtek HT16K33 LED controller, which also handles the board's four button inputs.
If the layout of the TinyNumberHat looks familiar, you're likely thinking of the Pitanga — another of Todoroi's Raspberry Pi accessories designed around the HT16K33, but using six dot-matrix LED display modules. As a result, the TinyNumberHat may be smaller — but it can display numbers 1,000 larger than its predecessor.
More details are available in Tudoroi's Hackaday.io page, while design files and software source code have been published to GitHub under the permissive MIT license.
