Robert Price Builds an RC2014 Music Player, Controlled with a Custom Rotary Encoder Input Module
The well-respected eight-bit RC2014 microcomputer family can now use rotary encoders — as the input to a jukebox, no less.
Vintage computing enthusiast Robert Price has spent the last month putting together a rotary encoder input board for the RC2014 modular microcomputer — and has capped the project off by building an RC2014 music player which uses it for control.
"I wanted to put together all my learning and build a music player for the RC2014," Price explains. "This will run using my RC2014 Classic 2 computer. It uses the LCD Driver Module, and the YM2149 Sound Card Module from Z80Kits. In addition, it also uses my ROM board and of course the Rotary Encoder Module."
Spencer Owen's RC2014 is a family of multi-board computers inspired by the Altair 8800 and other classic microcomputers. Typically based around a Zilog Z80 processor, though with more compact emulated versions available that swap this out for a modern microcontroller, the RC2014 can be expanded through the use of accessory boards — like Price's rotary encoder input board.
"I was able to tweak the existing PTPlayer example code from the [Z80Kits] sound module to insert my rotary encoder detection routines into the main loop," Price explains of the proof-of-concept project, which uses the rotary encoder to select from a range of audio tracks. "In the loop I would then move the arrow in the display if necessary, and change the current track if the rotary encoder was pressed.
"The one thing I have found is that if I turn the rotary encoder too fast," Price admits, "it doesn’t always correctly pick up the turn. This is because there is a lot more happening in the loop playing the music so the encoder isn’t being sampled as frequently as in my test code."
More information is available on Price's blog — though if you're interested in the development of the rotary encoder board itself, rather than the music player, you'll want to start at the beginning.