DBloke
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Re: Modified Spectrum

Mon Jan 09, 2012 9:51 pm

I came acorss a guide on line from soem one that has a PC inside a ZX Spectrum case (The keys working aswell).

Major problem is the parts, well one of them. He used something called a begal board, its cost is over £100, for that pirce I could get a old PC and put the speccy strpies on it. So my idea is.

48k Specturm shell (insides are broken anyway)

Wired up keyboard

Raspberry Pi

Possible mouse in a tape box

I shall call it

The Specberry Pi

(Im also going to have it running C64 games to confuse people)

plugwash
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Re: Modified Spectrum

Tue Jan 10, 2012 12:29 am

Interfacing the Pi to the spectrum's keyboard is definately doable. It's just a standard key matrix.

You could use the controller out of a PC keyboard but personally i'd rather use a USB pic since it will allow me to control the mapping from the keyboard matrix to the scancodes linux sees. If you use the controller board from a PC keyboard you will most likely end up with a screwy scancodes unless you are REALLY lucky.

While you can probablly work around the screwy layout in software under linux i'd much rather have a converter that produced the correct scancodes so that I could easilly swap images between the modded spectrum and other Pis that had regular keyboards attatched.

Before committing to the project i'd test spectrum emulation on a Pi, I can't see it being a problem but it does pay to check. Not sure how the OMAP on the beagleboard compares to the broadcom chip on the Pi

DBloke
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Re: Modified Spectrum

Tue Jan 10, 2012 1:47 am

There are a few Speccy emulators for different Linuxs.

(Ok im a noob to Linux)

The keyboard hack is shown here

http://www.flickr.com/photos/z.....543421081/

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Mezo
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Re: Modified Spectrum

Tue Jan 10, 2012 3:27 am

Yep its been done with a Beagle board & the details are here,

http://technabob.com/blog/2009.....c-casemod/

You may need a new keyboard membrane, can be had on ebay or here,

http://www.rwapsoftware.co.uk/.....ranes.html

Who`s going to "hack" the first Speccy then with a Pi ? im guessing evyones thought of doing it? what about a Rasberry Pi ZX Spectrum Laptop like this guy did.



Mezo.

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Chromatix
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Location: Helsinki

Re: Modified Spectrum

Tue Jan 10, 2012 8:32 am

That actually reminds me.  I've got an old 800x600 TFT screen from a PowerBook - and even a Spectrum +3 somewhere.

Mind you, I could just adhere an R-Pi to the inside lid of a BBC case and really confuse everyone.  Wouldn't even have to remove the genuine Beeb parts first!
The key to knowledge is not to rely on people to teach you it.

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Mezo
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Re: Modified Spectrum

Tue Jan 10, 2012 8:39 am

Chromatix said:


That actually reminds me.  I've got an old 800x600 TFT screen from a PowerBook - and even a Spectrum +3 somewhere.

Mind you, I could just adhere an R-Pi to the inside lid of a BBC case and really confuse everyone.  Wouldn't even have to remove the genuine Beeb parts first!



If its going to be a speccy its gotta be the original to be hacked, the size, the look (rainbow) and them glorious rubber key buttons.



Mezo.

DBloke
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Re: Modified Spectrum

Tue Jan 10, 2012 11:41 am

Well the sooner I get my slice of the pi (sorry) the soon ill get started, wanted one for the Homebrew geekend I have planed (end of January), but its looking like I wont have it by then.

As far as the BBC goes, its already easy to hack. Ive seen people do all sorts to it (Including adding a USB port).

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TonyD
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Re: Modified Spectrum

Tue Jan 10, 2012 1:29 pm

plugwash said:


Interfacing the Pi to the spectrum"s keyboard is definately doable. It"s just a standard key matrix.

You could use the controller out of a PC keyboard but personally i"d rather use a USB pic since it will allow me to control the mapping from the keyboard matrix to the scancodes linux sees. If you use the controller board from a PC keyboard you will most likely end up with a screwy scancodes unless you are REALLY lucky.

While you can probablly work around the screwy layout in software under linux i"d much rather have a converter that produced the correct scancodes so that I could easilly swap images between the modded spectrum and other Pis that had regular keyboards attatched.

Before committing to the project i'd test spectrum emulation on a Pi, I can't see it being a problem but it does pay to check. Not sure how the OMAP on the beagleboard compares to the broadcom chip on the Pi



I'm pretty sure there's a USB keyboard library for the Arduino. You could used that to translate the Spectrums XY keyboard matrix into scan codes and send over the USB.

You could probably roll you own h/w interface using the R-PI's I2C or SPI interface and a Port I/O expander chip.
Tony

PeteT
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Re: Modified Spectrum

Tue Jan 10, 2012 2:54 pm

Can anyone suggest a USB pic to use as Plugwash states?:

You could use the controller out of a PC keyboard but personally i"d rather use a USB pic since it will allow me to control the mapping from the keyboard matrix to the scancodes linux sees. If you use the controller board from a PC keyboard you will most likely end up with a screwy scancodes unless you are REALLY lucky.

Also any websites giving information on doing this? I want to use the Pi in an old and of no use to me at mo Tandy WP-3 which has a brilliant keyboard.

Thanks

PeteT
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Re: Modified Spectrum

Tue Jan 10, 2012 2:57 pm

forgot to say cheap as can be!

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Mezo
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Re: Modified Spectrum

Tue Jan 10, 2012 10:31 pm

If you read the Scottish lads flickr page (third post for the link) he used a cheap rubber keyboard & hacked it that way, bit of trial & error with mixed results at first but he nutted it out & got it working fully in the end, they are cheap.



Mezo.

plugwash
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Re: Modified Spectrum

Wed Jan 11, 2012 12:27 pm

PeteT said:


Can anyone suggest a USB pic to use as Plugwash states?:


Any 18F series with USB should be fine, personally i've used the PIC18F2550 and PIC18F4550 (which are basically the same other than the pin count) for my USB experiments but it's getting to be an older chip now. and I belive the more recent chips offer better bang per buck.


Also any websites giving information on doing this?


Microchip have a USB keyboard example in their application libraries. Which should deal with the USB side of things,  If you are using the 18F2550/18F4550 start from the "picdem FS USB" version of the examples.

I dunno if they have any examples that actually scan a keyboard matrix but it's not exactly difficult. Outputs to one side of the matrix, inputs with pull-downs to the other side of the matrix then raise the outputs one at a time and see which inputs go high.


I want to use the Pi in an old and of no use to me at mo Tandy WP-3 which has a brilliant keyboard.


The first thing you need to do is either find documentation of the keyboard matrix or figure out it's layout yourself from inspecting the hardware.

PeteT
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Re: Modified Spectrum

Wed Jan 11, 2012 3:45 pm

Many thanks for the information Plugwash. I have the technical manual for the machine so have more information on that front than I know what to do with! Thanks again

acrux
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Re: Modified Spectrum

Wed Jan 11, 2012 5:34 pm

as speccy emu on linux i gue the best one for little box is: fbzx .

It runs fine on framebuffer and i currently tested it (ok, just a bit slow but still usable) on old P166mmx laptop (with CRUX linux).

Btw, i really like to have a QL emu too.

monk3yfurr
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Joined: Sun May 13, 2012 3:23 pm

Re: Modified Spectrum

Mon May 28, 2012 3:19 pm

Hi - i've written + tested some arduino code to scan the zx rubber keys and convert the scancode, if you go down the arduino route let me know and i'll upload the source code. Not sure if the PI is going to fit inside the zx spectrum case - liking the idea of stand-offs and longer screws (maybe a few internal led's to glow the gap).

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