EZIO + OS9 + Hypercard (Or Just Windows)
The EZIO Board is a serial-based I/O module that can connect to both Windows and Macintosh machines. Actually, it can connect to anything that speaks RS-232. One of these came up on eBay recently and I couldn't resist. I saw the Macintosh serial port and decided to give it a go. It's really similar to an Arduino, but from a few decades before the Arduino was even a dream. If I'd known about these back in the early 2000s then I would've definitely had a very nice automated model railway. But alas, I only happen to find one now thanks to eBay!
The unit has 10 digital output lines, 10 digital input lines, 8 analog-to-digital lines and two PWM lines. You then get 4 +5v terminals and 4 GND terminals. There's a PIC microcontroller in the middle running the show and a MAX232 for the RS-232 comms. The unit has a DC-rectifier, so you can feed it 5-15v either AC or DC. The 5-15v is literally the operating recommendations of the 7805 voltage regulator on-board.
There's a whole lot of code on the old site (yeah, you have to use web archive to get to it), but it's mainly for Director!? and Macintosh. Hilariously, the Macintosh example uses Hypercard! Before booting up the Power Mac, I instead wrote a quick bit of C# to test out the unit.
The shot above uses dotnet-ncurses, allowing the console to act like a canvas. It's really nice to be able to draw text to specific areas, rather than scrolling the screen. Anyway, the basic idea is that you can control the digital out and then everything else is read in. Interestingly, floating pins show some very random values... so if you're using this device, make sure you tie everything to ground or use pull-up resistors where appropriate.
Of course, the whole reason I bought this was due to the Macintosh serial port. I wasn't overly-energetic, so I tried a virtual Macintosh first...
After installing Hypercard, the app came up, but the performance once it started trying to interact with the serial port was terrible. It also just didn't work, so I gave up and booted up the Power Mac.
Yup, works a charm. Hypercard is pretty clunky, but I'm sure you could do a lot with it. I'll have to dig out the railway track and control a train!