Telethon Display

For the upcoming Telethon (live on YouTube 1:00-6:00, April 26!), I've been asked to come up with a way to display the amount we've raised. To do this, I'm using a Pi Pico (though any microcontroller would work!), a ULN2003AN Darlington array, and the classic SN74HC595 shift register. This method, while more difficult than a dedicated control IC, will allow the full current of the display at all times with no flickering. 

This method also allows chaining of multiple displays simply by connecting the output of one digit to the input of another, a common technique with shift register making it simple to drive and number of digital output pins with just three wires.