sega dreamcast laptop started

[kylerock96]

Hey whats up everybody, this is my first post as well as my first project,i plan on making a sega dreamcast laptop out of the system, a keyboard which has a switch to switch from third player to keyboard, and a 15"/17" screen.

First off, the main thing i don't know how to do is how to route power from the sega dreamcast to the screen on one cable, if all else fails, i cna just use an extension cord with a 2 way splitter on the inside.

Second, how would i go about making the 3rd player port switch from the controller to the keyboard.

Will post pictures of my design soon!

[kylerock96]

bump...

I have my design done, but i need to make a scale mockup, i just don't know the dreamcast dimensions, could someone help!?

[kylerock96]

tjese are the designs i have made, they are just not up to scale

[bassmasta]

bump...

I have my design done, but i need to make a scale mockup, i just don't know the dreamcast dimensions, could someone help!?

http://forums.benheck.com/viewtopic.php ... 1&p=407122" onclick="window.open(this.href);return false;

[kylerock96]

Thanks for that link, I will be doing the vga mod on my dreamcast, but i don't want to use a switch, the guide i have tells me how to do it without a switch, so i need to look into that. If anybody on here would be willing to sell/donate a dreamcast, that would be greatly appreciated.

[kylerock96]

what pico psu rhould i use?

[kylerock96]

How would i wire tact switches up to the keyboard, just like i would on an nes controller for it to use tact switches?

[kylerock96]

Okay, i messaged ben and he said keyboards use a row any column format. Does anyone know what this means?

[Snow_Cat]

It means that each 'key' on the keyboard is connected to two wires.
Every key on a row is connected to the same wire.
Every key on a column is connected to the same wire.

For example:

Code: Select all

` 1 2 3 4 5 6 7 8 9 0 - = ⌫
↹ q w e r t y u i o p [ ] \
⇪ a s d f g h j k l ; ' ↵
  ⇑ z x c v b n m , . / ⇑
⌑   ◊ [space bar] ◊   ⌑

If we were to number each rowand column from the top left starting with zero, then ` would be column0,row0;
It would connect to the row0 wire with 1,2,3,4,5,6,7,8,0,0,-,= and ⌫.
` would also share the column0 wire with ↹, ⇪, ⌑, and maybe (⇑).

Similarly q would be column1,row1
- w would be column2,row1
- e would be column3,row1
- etc.

[kylerock96]

So, i hook one side of the tact switch up to the ic, and then the other side to... what?

[argelfraster]

Ground.

[kylerock96]

so, tedious but possible?

[Snow_Cat]

No, not ground. Not unless the keyboard decoder has 96+ pins, one for each key.

Each key connects two wires, a row and a column. the encoder chip in the keyboard setects which two wires are connected and then sends a keycode to the console.

Attached is an example design using 6mm tact switches and two headers.
On the bottom (blue) layer every button is in a column is connected on one side to the same pin/wire in the column header.
On the top (red) layer every button in a row is connected on one side to the same pin/wire in the row header.

The decoder has pins that connect to each row/column.

mc.pp.seDreamcast programming - Keyboard shows us that a Dreamcast keyboard has 96 keys in six rows and 18 columns; however there are 104, and 88 key versions that will have a different matrix layout. the attached example isn't perfect, keyboards are rarely square grids, and keys are not always exactly one gird wide; so if yo use this you will probably need to relabel some keys; or look at the original membrane to see what key connects what two wires.

Pro tip: most tactile switches/buttons connect the two pins on one side together; so it is possible to run a signal in one leg and out the other. This makes making PCB's cheaper, and the attached example makes use of this.
Only the bottom layer is needed if all of the solder joints and traces are good.
In case you do decide to use it, I've deliberately designed the two layer version to have parallel circuit paths (of equal length) meeting each switch in two places so that it will keep working if something breaks.

edit: attachment refused, "Sorry, the board attachment quota has been reached." it says.

docs.google.com2010.09.11.pdf
Sorry, but Google has corrupted it; it can nolonger be used to produce a PCB directly, and is only an illustration.

wait, tried again, it is now downloadable.
docs.google.com2010.09.11.pdf

[kylerock96]

kay, that sounds too complicated for my first project, i think i will just lug a keyboard around instead of just integrating one.

[Snow_Cat]

2010.09.20
Please don't dispair;
It only sounds complicated because I am not very good at explaining things without being able to poke things w/ a stick.

Look, I have a few hundred keyboards.

Spoiler:

• rather than pay wase disposal fees the last four labs/GI's I've worked for have dumped loads of filty mice, keybards and PC's at my home, after I quit...

What I'll do is take a few more apart and try to explain better with a slide show tommorow.

Spoiler:

• Oddly enough, except for the Model M's, these are the keyboards that I've paid for.

edit 2010.09.21: this is taking longer to compose than I anticipated.