8-Digit Scrolling Text Display with Shift Registers and a PIC16F1455 MCU

FriendlyWire's 7-segment display features custom expandability and adjustable scrolling speed.

Jeremy S. Cook
3 months agoDisplays

If you’ve never tried it, you might assume that creating a scrolling display with 7-segment modules and shift registers is a moderately advanced and difficult project. While you could certainly argue that it’s harder than blinking an LED, as shown by Jens at FriendlyWire, it's actually not that hard when you understand the concepts involved.

In the build video below, Jens goes over how a shift register works, using the analogy of a conveyor belt that gets bit data, applies it to each register pin in sequence, then outputs the ‘exiting’ data bit by bit. These data pins can be used to power a 7-segment display unit, so an 8-bit shift register works out perfectly here. The next shift register can simply be stacked up to the output pin to display the next character sequentially. This process can be done over and over to form a scrolling display. While this project uses eight characters, there’s no reason it couldn’t be expanded to whatever number of digits that you need.

This particular device uses a PIC16F1455 microcontroller for processing and CD4094 8-bit shift registers. A potentiometer is added to control scrolling speed, along with a button for text selection and a power toggle switch. All of this is stuffed in a wooden pencil box and diffused with plastic cut from a file folder. The results are fun, and it looks like a great way to learn about this fundamental technology!

[h/t: Reddit]

Jeremy S. Cook
Engineer, maker of random contraptions, love learning about tech. Write for various publications, including Hackster!
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