7 segment displays are a well established way of electronically displaying numbers and a small set of letters. They’ve been around for as long as I’ve been playing with electronics but were a pain to wire up given the number of LEDs involved.
Luckily things are a lot easier now that they are available on pre-made modules that uses an SPI interface. This is easy to setup and use on the Raspberry so for about £3 you can add a strip of 8 7 segment digits.
These modules tend to all use the Maxim MAX7219. This IC does all the hard work and we can communicate with it using SPI and a few lines of Python.
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