It's Alive!

Business cards may be outdated in today’s digital world; however, there is still no quicker way to give someone your contact information when meeting in person, so they are not likely to go away any time soon. That does not mean that technophiles are content to live with fifteenth-century technology, however. A popular trend among hardware engineers is to build custom printed circuit boards (PCBs) that serve as business cards — only way more interesting. We have seen examples that simulate the flow of a liquid or play the snake game, for instance.

Now, Binh Pham has taken boring old business cards to the next level with a PCB that runs a large language model (LLM) entirely on-device. With its unique theme, it is sure to be a hit at Halloween parties this Fall. Called the Bouija card (a mash-up of “Binh” and “Ouija”), it has an eerie user interface covered with LEDs that blink out messages from the poor computer algorithm that is forever locked away inside the board’s silicon.

The Bouija card PCB is populated with an ESP32-S3 microcontroller with 8MB of PSRAM and 16MB of flash memory, a USB-C charging circuit for power, capacitive touch pads, and a bunch of LEDs. 40 LEDs in total were included — one for each letter and number, and a few for special purposes.

As far as the firmware is concerned, most of the work was already done. Pham relied on the library previously created by Dave Bennett that makes it possible to run a small LLM trained with the TinyStories dataset on ESP32-S3 microcontrollers. This model contains 260,000 parameters and it can only generate small and simple stories, so it is nothing like carrying ChatGPT around in your pocket, but it is an interesting novelty all the same.

After integrating the existing library with the capacitive touch sensors and LEDs of the Bouija card, Pham had a very unique, and spooky device. It can blink out the text of short stories on demand, and it works pretty well. Tests revealed that the ESP32 chip can churn through about 24 tokens per second. Not bad at all.

Pham's business card is an inexpensive way to impress potential employers or clients, entertain yourself, and spook your friends this Halloween, so why not make your own? If you are game, there are plenty of details available on GitHub to get you on the right path.