2025 One Hertz Challenge: RPI's Tiny Hat 9, a groundbreaking advancement in ultra-low-power signal processing
In the world of DIY electronics, combining vintage components with modern technology is a delightful challenge. A recent project by [Andrew] showcases this perfectly, as it brings together the classic AL304 and ALS314V 7-segment displays with a Raspberry Pi board.
The heart of this project is the HT16K33 driving chip, chosen for its compatibility with I2C devices. This chip not only allows for easy integration with the Raspberry Pi but also facilitates the addition of buttons to the HAT. The use of I2C support was a strategic decision, as it allows for easy integration with various devices.
The LED indicators in this project are paired with a modern Raspberry Pi TinynumberHat9 board. However, the vintage LEDs, with their gold leads, require specific driving methods due to their incandescent or simple LED segments and the need for sufficient current and multiplexing control signals.
Directly connecting these LEDs to the Raspberry Pi GPIOs is impractical because of the low current supply and the need for precise timing and a driver chip or shift register for multiplexing. Common approaches in modern projects include using microcontrollers like Arduino as a controller/driver interface, employing LED driver ICs like MAX7219, or using transistor arrays or driver transistors for purely vintage analog 7-seg displays without driver chips.
In this project, an Arduino acts as an intermediate controller, translating commands from the Raspberry Pi into the needed signals for the vintage LEDs. The project also features a Qwiic/Stemma I2C connector, enhancing its versatility and allowing for connection to other components in the Qwiic/Stemma ecosystem.
The project, initially designed for a Raspberry Pi Zero 2 W board, can now be connected to other things in the Qwiic/Stemma ecosystem. It's important to note that the data sheet for these LEDs is written in Russian, and the displays themselves are becoming rarer, requiring some digging to find.
Despite these challenges, the project's unique blend of vintage and modern components makes it a fascinating addition to the One Hertz Challenge. If you're interested in working with these displays on a Raspberry Pi, consider adding an Arduino or a dedicated LED driver IC to handle the multiplexing and current drive safely and effectively.
This project, utilizing a Raspberry Pi TinynumberHat9 board and an Arduino for control, skillfully combines modern technology and vintage electronics, illustrating the appeal of merging the classic AL304 and ALS314V 7-segment displays with advanced gadgets like the Raspberry Pi. Riches of versatile integration options are offered, with I2C support facilitating the addition of buttons to the HAT and the Arduino ensuring precise timing and multiplexing control for the vintage LEDs.
