A countdown counter with the MAX7221 and a seven-segment display


A close look at the MAX7221 reveals that the device is ideal for controlling LEDs: It supports up to 64 individual diodes, the design does not require any series resistors, and the brightness of the LEDs can be adjusted through the module. By the way, if the eagerly awaited event is very far into the future, you should consider finding a more energy-efficient supplier of SPI signals than the Raspberry Pi, such as an ESP8266.

The Author

Born in the era of magnetic core ring accumulators and rotary dial phones, Martin Mohr developed a love for everything that flashes at an early age. After studying computer science, the qualified electrician developed Java applications. His old passion for electronics was revived by the Raspberry Pi.

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