Seven-Segment UART Display

While modern computer monitors are fantastic for general usage, there’s still something charming about a glowing red seven-segment character output. If you’d like a way to translate information from a computer into this format, then Davide Gironi’s AVR serial to eight digits seven-segment numeric display could be an excellent solution.

The aptly named "avr_serial7segment8bitdisplay" shows two rows of eight seven-segment characters, which are controlled via UART from your computer. The device takes input over USB using a simple protocol explained in the device’s blog post, and after CRC verification, shows the expected numbers on-screen. It also saves the last set of numbers on display in EEPROM, so if you cycle the power it will maintain its previous state.

Hardware-wise, the system employs an ATmega8 MCU for control, along with a pair of MAX7219CWG drivers to interface with the LEDs. A CP2102 chip is embedded for UART-to-USB conversion through a micro USB port. Gironi even 3D-printed a nice enclosure for it in PLA to finish things off.

The unit was tested via a PowerShell script, and you can see it in action in the video below. Given its straightforward operation, it should be possible to use it with a variety of other setups depending on your system and preferred programming environment. One could see the avr_serial7segment8bitdisplay implemented to track currency exchange rates, stock prices, or anything else where the simultaneous display of two numbers would be beneficial.