Digit Displays Using Shift Registers

As part of a larger project, I needed some 7-segmented digit displays.


I had some cheap ones lying around, and I forgot where I bought them. Thankfully, I found the data sheet here. Since running 16 lines from an Arduino would be quite wasteful, I designed them to be controlled by two shift registers. Here is the information I used to wire it all up. Shift register wiring can be found here.


Note that since I was soldering to the back, I flipped the pinout of the digit displays. One shift register controls each digit, and the first shift register passes information to the second.

For code I used the shiftOut function. That turns on the LED’s with a binary number, so it comes down to seeing which binary number creates what displayed number. I made a table to figure it out. So now all you have to do is send a number between 0 and 99 to the displayDigit function.




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