I've wanted to build a dedicated Spectrum emulator for a long time.
I live in America now, and all of my original hardware is back home in the UK.
I've also got used to the luxury that emulators offer, such as instant loading, vast storage, save slots etc.
When the Raspberry Pi came out, I realised that this would be the perfect machine to base my emulator on.
It's tiny, cheap, and requires no fans or special cooling.
I decided to build a machine based upon the ZX Spectrum Plus, which was the model I originally had as a kid.
I wasn't hoping to make an exact replica or anything, but I decided to follow the general lines of the original machine, ie. a keyboard with a smaller 'box' underneath.
I did consider buying one of those flexible silicone rubber keyboards and making a rubber key Speccy, but decided against it.
I do own a rubber key model, but the one I originally had as a kid was the Plus with its 'professional keyboard'
I also like playing text adventures, and a silicone keyboard would have been horrible to type on....
It's almost finished now.
I have just got to make a bottom cover, which I'm going to make out of a 2.1mm sheet of aluminum.
I bought a mini usb keyboard, and stuck some strips of thick ABS sheet to the bottom to make a rectangular frame.
I used a technique called 'solvent welding', which is similar to the way Airfix-type models are stuck together.
The keyboard housing is also ABS plastic. I welded the parts together by using a 'goop' made by dissolving ABS plastic scraps in acetone.
This stuff melts and fuses the plastic pieces together, then the solvent evaporates, leaving behind a welded joint with about 75% of the strength of solid ABS.
By building up the seams, you can get incredibly strong structures. You'll see a seam at the rear of the machine that I didn't sand down fully, because doing so would have made it weaker.
Once I had the frame in place, I installed the innards of a usb power supply, then boxed it in with more ABS sheet to isolate the dangerous voltages.
Then I shortened the usb cable from the keyboard, mounted the Raspberry Pi, and hooked everything up.
The only thing that remains to be done is to hack a usb game pad and wire it up to the 9-pin D-sub connector on the front so I can use standard Atari-type joysticks such as my Competition Pro.
The machine is running the SDL version of the Fuse emulator, and has the entire WoS archive on it
I just need to set it up so that the machine boots straight into Fuse on startup, and get rid of the stupid mouse pointer that is always in the top left hand corner of the screen
Having this machine has really made using an emulator more realistic. The whole feel of the experience is very close to using a real Spectrum.
Tiny cramped keyboard linked up to the TV with a cable, no windowing system to remind you that you're using an emulator.
With SDL Fuse, even the emulator menus are in the native Spectrum font.
If you turn off fast loading, (for novelty purposes only) you can recreate the entire experience, minus the tape recorder of course...
Here are the dimensions:
Real ZX Spectrum +
W 320mm
D 140 mm
H 40mm
My emulator
W 282mm
D 128mm
H 45mm
So as you can see, it's ever so slightly smaller except the height, which is 5mm greater.
I couldn't make it any thinner and still have room to enclose the power supply, but it was worth it for safety reasons, especially as it has a metal bottom cover.
The power supply unit is completely enclosed in plastic except for the +5v output.
I could have used a smaller psu, but I had a high quality one lying unused because it had a UK plug. I removed the guts and mounted them into the chassis.
It was a bit of extra work, and made the machine a little taller than the real Speccy, but it is a really nice psu with a very clean output, so it was worth it.
