Easiest way interact with circuit from computer?

Thread Starter

MartinLarsson

Joined Feb 25, 2009
17
What is the easiest way to interact with a circuit from my computer?

When I'm saying interact I mean control outputs and perhaps receive inputs as well. I have looked around and read stuff about parallel ports and they are easy to control output. But what about input?
Then I know there exists verses thingys to connect to USB, to control a board of some kind.

I want the electric to be easy - not the programming necessary. And it doesn't hurt if it's cheap. :D

Thanks!
 

beenthere

Joined Apr 20, 2004
15,808
That is awfully broad - can you be more specific about how many inputs and outputs and what the nature of the control is?
 

Thread Starter

MartinLarsson

Joined Feb 25, 2009
17
The input/output number doesn't matter, three of each at least.
I was just thinking of something simple like a LED or so. It would be good if it wasn't just on/off. Like you can vary the voltage. I don't really know much about this kind of stuff, but pretty much anything will do.

I just want to hear what you recommend for a somewhat newbie.
 

beenthere

Joined Apr 20, 2004
15,808
That raises several issues. You mention a parallel port, so I will guess that your computer still has one. The outputs - and inputs, with the correct operating mode - are digital. That is, on or off, with no state in between.

Changing the apparent illumination of an LED would require control or an output bit to do PWM (pulse width modulation). It will alos require the use of a language that allows hardware-level access. That is not possible in Macs, and only through the use of some varieties of C or assembler or one of the modern Basics in an Windows XP system. It may not be possible with Vista.

Varying an output voltage requires a device like a Digital to Analog converter. If you understand the principles, the parallel port can be used to control a homemade D to A, once again with hardware level access.

Here is a link to a site that has quite a lot of information on using the parallel port - http://www.beyondlogic.org/ecp/ecp.htm.

We have any number of threads extant on PWM if you care to investigate that.
 

Thread Starter

MartinLarsson

Joined Feb 25, 2009
17
Ty, I think I'll go with the parallel system.
However, is it worth buying an Arduino? Unnecessary question but... If they are like super awesome, then I would considder buying one.

Thanks!
 
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