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First thing to consider was what I could achieve with the single biggest limiting factor, the operating system and hardware. It simply was not going to be possible to use the existing operating system of a pin as coding in machine code and burning on to a ROM would have serious limits on the amount of video and sound I could use. Also, I wanted to make a system that anyone who is conversant with simple programming languages could reasonably be expected to program a game in, the eventual idea being to offer a kit to allow anyone to make their own machine.
I needed a relatively cheap powerful platform with good graphics and sound, huge storage capacity and the ability to run code in a language of my choice. It should also need little cooling to remove the need for fans.
The obvious choice was a P.C. but there is a myriad of machines and specifications to choose from. I took over 4 months to spec the Mini ITX P.C. Chosen for its small form allowing mounting in the back box if required, along with its on board support for LCD and S Video displays and 5.1 digital sound.
I didn't want to run Windows, mainly because I don't want to have to pay for a licence for every game I make and also because of its instability and tendency to freeze. Anyone who has played pinball on the pinmame system will have probably experienced the game slowing or freezing every now and then.
Linux was chosen for its real time capabilility, vital for game play, and its ready availability licence free. Linux is also small, has good I/O capabilities and if required can be modified by recoding the kernel to allow it to tailor exactly to what is required of it.
I wanted to mount a LCD monitor instead of a DMD mainly for programming purposes, I would not be able to "do the dots" and it didn't seem possible to make it work easily with the P.C. So I started searching for a suitable, cheap LCD display. Another 6 months turned up a 9" widescreen display with decent enough brightness, viewing angle and resolution. A combination that seems very hard to find. Since I have found this, I have talked to Nick at pachinkos.co.uk and it is now apparent that some of the widescreen displays used in these would be a good choice.
As the P.C. had a good sound system, it seemed a waste to skimp on the sound system. After reading Korns pages regarding the custom sound systems he has added to a few machines, car audio system components appeared to be the cheapest way to get big bang for the bucks. There is plenty of reading on the internet regarding hooking up a car amp and speakers to a P.C. Although finding the 20 amp feed in a pin is more difficult. More on this later.
So I now have Audio Visual specced and CPU sorted, this just leaves how we will physically operate the game, including solenoids and lighting. Originally, I was going to make 2 boards, one for solenoids and one for lights. This would be similar to the 80's '35 MPU set up in Bally machines, I was going to interface these using RS232. I ran nto problems with this as I still needed a power supply and the design and build of these boards was proving prohibitively expensive. Also a lot of people I spoke to had concern that the RS232 format would not be reliable or quick enough. I decided in the end that using a WPC power board would be the way to go. This has power, lighting and solenoids all in one. To this I will add a daughter board to interface the USB to the existing ribbon cable.
The final thing to sort hardware wise was how to turn the pc and machine on or off. Simply flicking the existing power switch will not be acceptable in a P.C. environment. I will make a power controller board to do this, but see later for a schematic and details.
A lot of the above is an oversimplification, treat it as an overview. The following pages will go into detail as and when I get solutions.
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