Hearts and Brains...The Guts of Gothic
Gothic's brain is an AMD K6-2 300mhz PC running Windows 98, interfacing to the physical playfield and cabinet via custom-designed interface boards. The heart of Gothic is an Epson Equity LT laptop, circa 1990 (10mhz 8086, no hard disk, CGA display!).
We designed and built custom PC boards to handle the interface between the CPU and the physical elements. These connect to the CPU's parallel ports.
The input interface is a 16x8 switch matrix (128 switches), software scanned at at least 3Khz. Currently, only half the matrix is wired until the design demands more switches.The output driver can handle combinations of up to seven daughter cards of three basic flavors:
-an 8 output transistor solenoid / flashlamp driver (in both high and lower current versions)
-an 8 output relay driver board (for switched AC or contact closures),
-a lamp driver capable of driving about 200 discreet lamps or LEDs (0-30VDC, 200ma)
These daughter cards can be mixed and matched in any combination as demanded by the playfield layout. Gothic's current configuration is 2 solenoid boards, one relay board and one lamp board--leaving three positions available for more solenoid drivers or ??? I've currently used up almost all of the solenoid transistor outputs, so another transistor board is coming soon.
The solenoid's main power (25VDC) is controlled through a hardware watchdog timer & relay that must be actively strobed by the computer's software with a specific handshake at least every 30ms or it will automatically kill power. Should the computer crash or an uncontrollable lengthy delay happen, the coils will de-energize automatically.
Lamp and solenoid main power passes through heavy duty circuit breakers and fuses. Main AC power is fuse protected. Individual coils are protected by individual fuses.
A relay is connected in parallel with the solenoids, which allows the input switch matrix to determine if a coil is energized. Should a coil remain energized too long due to a short, blown transistor, or bad software logic, the computer will be able to detect it and kill the power.
We are currently on our second playfield--the first had a few basic elements and layout, but was not painted.The current playfield is hand cut, routed, sanded, hand painted, and hand sealed. It is an original, not based on any existing pin layout or design. In the next version, we will be creating the playfield art digitally using machine-cut vinyl and inkjet prints on vinyl, although the style will remain "painted" rather than photorealistic (i.e. the difference between Williams playfield art and that of most recent Sega machines). While painting a playtest whitewood may seem silly, we are still honing the design and artwork process as well as the shots and layout.
The playfield is completely wired for lamps, switches, coils, etc. but missing the upper playfields. The design of the upper playfields will probably be reworked somewhat and integrated into the next generation "whitewood" as we've come up with some better ways to handle getting up and down from those upper playfields. We will also be redesigning the ball launch and entrance in the next playfield.
Mechanical parts are salvaged pieces and spare parts from many other machines, which have been reconfigured. Most of these come from mid 70s EM machines, because that's what I happened to have available. I would have preferred to use some of the more advanced modern mechanisms, but I didn't have a modern machine as spare parts. As we go through the whitewood playtest phase, I may upgrade some of those parts to their more modern counterparts.
The current backglass is hand painted to keep with the stained glass motif of a Gothic Cathedral. We are current redesiging it digitally, and it will be printed on translite.The display is the main CPU's VGA display capable of animations and distinct display fonts. We chose a grayscale display viewed through a red filter to avoid a too-colorful "video game" look.
(See Photos) Themed to look like a burial casket, the cabinet is pretty simple. Those doors are NOT from a Safecracker, they are fold-out elements representing the Gothic arch, and may be used to focus stereo sound towards the player.
The cabinet & legs are the only complete pieces used from an existing machine: it's an empty wooden box from a Chicago Coin HeeHaw (1976 EM). In retrospect, we would have preferred the extra design space a widebody would afford, but we'll just have to deal with it....