During this week I was able to break through some hardware difficulties, and unlock a secret I was fascinated with years ago: the field of the so-called Computer Interfacing, i.e. connecting computers to external peripherals and electronic circuits.
It all started back in school days, years ago. I had contact with people who were able to step outside software dimensions, and make programs that interact with outside world elements using sensors and actuators. The idea was astonishing, though I had absolutely no idea what bits look like outside computer cases back then :)
The closest thing I was ever able to do was arranging some bits on the computer’s parallel port (printer port). I didn’t know how to extract them or make use of them practically.
Through all those years I kept this in mind, and collected pieces of the puzzle one by one. It’s only this week that I’ve been able to link different software and hardware technologies together, and assemble something that actually works!
Well, for now I only got a blinking LED and a little animated show using a seven segment display. I was thinking of buying more ICs, sensors, and motors to play with but had second thoughts: I’ll think of a complex, yet feasible, project, then buy the parts and implement it. At least I’ll be out with something instead of having tested the operation of a bunch of ICs!
If you’re a computer geek, you’ll probably be wondering how this works. What I did was plugging the 8-data pins of the parallel port into a bread board, and sending bytes using the assembly OUT instruction to port 378H (address of parallel port). I also had to use a DLL to bypass a protection scheme Windows XP implements against I/O ports instructions.
After issuing the instruction, pins with logic high will rise to 4.4 volts, while those with logic low will drop to ground level. Those voltages are all what you need to power and interact with all kinds of circuit elements.
To power motors and heavy actuators, you’ll need higher voltage. Just grab one of the power supply cables which supply 12 volts (Yellow Wire) as well as 5 volts (Red Wire) and ground (Black Wires).
Most of you friends were excited as I showed you pictures I’ve taken of the circuit. I’ll keep you informed of any progress, keep checking :)
It all started back in school days, years ago. I had contact with people who were able to step outside software dimensions, and make programs that interact with outside world elements using sensors and actuators. The idea was astonishing, though I had absolutely no idea what bits look like outside computer cases back then :)
Well, for now I only got a blinking LED and a little animated show using a seven segment display. I was thinking of buying more ICs, sensors, and motors to play with but had second thoughts: I’ll think of a complex, yet feasible, project, then buy the parts and implement it. At least I’ll be out with something instead of having tested the operation of a bunch of ICs!
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