Hi, I'm a legally-blind Finnish uni student majoring in information processing science but have been interested in digital logic and symbolic machine language for some time. Thus I took a uni course called digital techniques which is dealing with digital logic, boolean and switching algebra and related topics. The course just began so I'm not totally sure what will or won't be covered.
So far I like the contents in the course but one really problematic area for me are the diagrams dealing with ports, switches and other components. These are sort of hard to read and even harder to write for various reasons. In the end it all comes down to having no useful textual representation for the charts, so I need to use heavy magnification and the mouse.
Reading the diagrams has a couple of difficult key steps. Firstly, many of the American port symbols resemble each other a lot so reliable shape detection with magnification is slow and tedious, though fortunately we are using the IEC symbols which are much clearer as a magnification user.
The text labels need to be read, too, which may take several seconds per element. Speech is of no help because most of the exercises have the imagery in bitmapped form. Lastly, the usable magnification range for me is easily at least 4x which gives only 1/16 of the whole screen. In practise this means that I can only examine a single element at a time and have to traverse the arrows, cables and other connective elements slowly one at a time. Thus it is easy to imagine this all takes lots of time and isn't really essential, understanding what's going on, getting the big picture and being able to ponder the logic is what counts, I think.
As far as writing diagrams goes, I'm currently using Microsoft Visio, which is a very general diagramming tool. It is able to do the job but very clumsily. I need to work with high magnification and do precise mouse dragging, clicking and such, to which I haven't really gotten used to, though I'm physically capable of using the mouse of course. WHen it comes to general computing, I like the GUI but am using the keybord as much as possible. I prefer fast speech to magnification or braille but screen readers aren't smart enough to understand the semantics or even the syntax in diagrams.
As an example of an awkward way of handling things in Visio, I should mention the wiring. In some other unrelated music tools, in stead of having to drop a wire object and drag both ends to where I want them, you connect modules by dragging from the output to the input. The wire is inserted automatically and snaps to the closest destination terminal clearly showing where it is going to go if I release the mouse button. Even better for me would be a keyboard interface. So I could type some uniquely identifying bits of texts or numbers to specify the source and destination from the keyboard, with no mouse dragging involved.
So, how do you do your diagrams and is there any alternative, preferrably accessible, Windows software or notation you could recommend to make the job easier? We'll be dealing with Switching and Boolean algebra and their various diagrams a lot as well as basic digital logic circuits.
On other courses I've been using various methods. For UML the Rational Rose Tool is actually pretty usable and doesn't involve an awful lot of mousing around. FOr ER and EER diagrams in databases, i invented my own notation that's 100 percent textual. As far as graphs and trees go, I found working with matrices loads easier than looking at a magnified, visual representation of the same thing on-screen.
But back to digital logic and switching algebra, do you know of any textual notation for representing these diagrams efficiently? Intuitively, I would think such a thing must exist. After all all size and spatial information in these diagrams seems redundant, only the ordering and relations of the elements really matters. I wonder what kind of notation people used to use when discussing electronics in newsgroups before graphical display devices and HTMl mail were around?
Finally, before I forget I should ask if the set of Boolean algebra symbols have been standardized in ASCII? Here's what I'm currently using: A' : unary not A a + b: a or b a . b or simply a b: a and b a ^ b: exclusive or (borrowed from the bitwise operator in C) (a b)': not and. The not spanning the whole expression is indicated with parentheses and I'm using the single quote sign as a postfix n-ary operator.
Hope you don't mind the computer science lingo, I have some programming background but am a total noob as far as digital logic goes.
PS: I'm not usually into cross-posting but this time the main message goes to alt.comp.blind-users and I'm also posting this to sci.electronics.misc hoping for a wider audience.