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ZZTOP SOFT

Controlling EM Pinball with an Atari 800XL

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Hi. I want to present my latest project: Controlling an electromechanical pinball machinne with an ATARI 800XL.

Unlike electronic pinballs, electromechanical or "EM" have no electronic components, so all its operation is based on relays, coils and coils with a combination of mechanisms (called banks or units) that allow a primitive form of data storage (RAM).

 

Well, my goal is to replace all this stuff with an Atari 800XL and buid a small controller board as an I / O.

 

The machine chosen is one of my favorites of the late 70's: Gottlieb's Centigrade 37. Recently a friend gave me just the playfield, in not very good condition, so I'll have to retouch some cracks and repopulate it, ie buy all post, rubbers, bumpers mechanisms, and many other things. Also rebuild a proper cabinet.

 

And finally the programming, which I will in Basic, by now, with the plus of being compiled and put into a cartridge to load automatically when you turn on the machine, like electronic pinballs does. Anyway I hope rewrite the program in assembly... later, to win some advantages of the processing speed.

 

Yeah, I heard about Arduino's and other similar hardware`s but this is ATARI AGE ¿right? We, and I, are from that time and I love it!

So... up and atom! :-D

 

This is the playfield I have

zenti1.jpg

 

and the cabinet

zenti2.jpg

 

 

Inside the cabinet of a real Centigrade 37

zenti10ca.jpg

As you can see, getting all those parts and wired it correctly are impossible. Besides very expensive.

When the project ends, the cabinet are almost empty.

 

ZZT

Edited by ZZTOP SOFT
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Neat idea! I'm very interested in seeing your progress. My parents were given a couple of partially-working pinball machines by my uncle a few years back, and this might give me some inspiration to try to get the mechanisms working again.

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Well, my goal is to replace all this stuff with an Atari 800XL and buid a small controller board as an I / O.

 

Depending on how much I/O lines you need, changes are you don't have to. The joystick ports are/is actually an 8-bit bi-directional data bus. Add to that the 2 extra inputs (fire buttons) and 4 analog inputs (the 4 paddles) and you're halfway done.

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Yes, nice.

 

But 8 bits I/O + 2 bits input only won't go far with a pinball. I think some sort of latch array via the PBI or cart port would be a very good idea.

 

On the software side, my initial impression was assembler or compiled language as a minimum, but if some sort of smart buffering system was employed, there's nothing stopping a slow old Basic program from controlling a pinball - albeit with the occasional bit of lag if things got busy.

 

ed - there's the paddle ports too, they could be employed in an A->D capacity or be used as extra digital inputs.

Edited by Rybags

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But 8 bits I/O + 2 bits input only won't go far with a pinball.

 

With mux'ing you can end up with 256 output and 1024 input signals. Looks plenty to me.

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You still have extra hardware outside needed - it's probably easier to just have addressable latches than employing a mux system similar to Pokey's keyscan arrangement.

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Yes, I already thinking in the BASIC speed issue, so, everything must be latched, I mean, score display, cpu controlled lamps, and whatever.

All the switches are other history, because can be connected directly to the keyboard, taking advantage here, because the keys are already latched by the atari itself. :grin:

The I/O method I'm going to use are similar to cartridge bank sw, with several type D Flip Flops.

So, the Atari Basic only have to scan the keyboard, sent data to the score display, turn on or off some light, and make a beeb ONLY when it's needed. And back to read the keyboard, meanwhile the IO board keeps the data itself. Enough for a machine like this EM Centigrade 37.

 

Stay tuned, this thing will move forward quickly... because will be my xmas gift. :-D

 

PD: A typical electronic pinball, of early 80's, updates displays (4 players), lights and read the switches THREE TIMES!! PER SECOND! In Atari BASIC that is impossible.

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Depending on how much I/O lines you need, changes are you don't have to. The joystick ports are/is actually an 8-bit bi-directional data bus. Add to that the 2 extra inputs (fire buttons) and 4 analog inputs (the 4 paddles) and you're halfway done.

 

OFFTOPIC (short):

I am a software guy, but I want to make some eletronic experiment. So some days ago I was wodnering what kind of voltage I can get out of the IO-pins of the joystick ports.

Do I get 5V? I want to drive a small speaker ;)

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I also believe that BASIC is a possible issue. I never used one, but I know some faster versions of basic and compilers were made. I would try and learn machine language for a project like this and take advantage of the amazing speed your atari is really capable of!

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Generally you don't use PIA outputs to drive stuff directly - I did an experiment some time back doing digital sound direct to an amplified PC speakerusing a latch and resistor ladder.

 

Also, PIA output isn't great for utterly time-critical applications. The rise time is variable and seems to be in the order of several cycles. But we're talking milliseconds here, for something like a pinball a few cycles here or there won't matter.

Edited by Rybags

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Generally you don't use PIA outputs to drive stuff directly - I did an experiment some time back doing digital sound direct to an amplified PC speakerusing a latch and resistor ladder.

 

I got an advent calender which does not contain chocclate. Instead, it contains parts for building an radio receiver :)

Teh first pieces were a battery, resitor (1k Ohm) and a loud speaker. At you could here a bit of noise when you connect the battery to the speaker and resitor.

So I thought, how boring, but using teh XL to paly teh sound would be a nice experiment :)

 

While writting this I realized, some kind of variable voltage output would be even cooler to regulate the volume of the sound. However, I don't think the XL features such an output? The only analoge channel is the paddle-in right?

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Paddle pots are the only variable input, the voltage I believe should be from 0-5V.

Problem is that the fast scan mode is needed, that loses some accuracy and takes 2 scanlines rather than 228 to generate the value.

 

That equates to about 8 KHz sampling, the lesser precision wouldn't be much issue if using Pokey voices to playback since you really only get ~ 6 bits effective precision.

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The cabinet I got its too wide, so... let's cut.

zenti3.jpg

 

zenti4.jpg

done!

 

And last night, I work in the playfield

zenti5.jpg

 

zenti6.jpg

 

zenti7.jpg

 

Tracing the missing parts of the artwork.

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This is awesome - I can't wait to see it when done. Keep posting pics of your progress too.

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Nice drawing skills.

 

If you want accurate copying / scaling from the images on the Internet, you may want to use the grid technique.

 

Draw grids on top of your original and scaled. That way you will ensure you get everything on the right position.

 

Good job, good luck!

 

 

gridexample-1.jpg

Edited by RodCastler
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Last Nitght I build a Score Display proto.

 

zenti11.jpg

It works!

 

I wash some old parts I have, to save money.

zenti13.jpg

Course, I'll use sand paper... latter. :D

 

And put them over the playfield, to see how they looks. And paint some red things.

zenti14.jpg

ummm, they looks pretty cool. Always is good see how a playfield back to life. I'm thinking in buy all (or some) those things, because its not much money in there.

Edited by ZZTOP SOFT
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OMG that is so sexy, I can't wait to see the project photos! I love pinball, but can never afford nor find the time for the hobby, not to mention I'm not that much of an electrical engineer which I feel to properly appreciate pinball you really need an engineering background of some sort. :)

 

Wow, PLEASE keep us updated. Got any other tables in your collection?

-A.

 

Edit: you're using digital score readouts? bummer. I imagine doing a scoreboard might be a little difficult. Have you considered something like Gas Discharge Displays?

Edited by Android8675

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OMG that is so sexy, I can't wait to see the project photos! I love pinball, but can never afford nor find the time for the hobby, not to mention I'm not that much of an electrical engineer which I feel to properly appreciate pinball you really need an engineering background of some sort. :)

 

Wow, PLEASE keep us updated. Got any other tables in your collection?

-A.

 

Edit: you're using digital score readouts? bummer. I imagine doing a scoreboard might be a little difficult. Have you considered something like Gas Discharge Displays?

well, engineer I'm not. But I have electronics studies. To attempt this kind of mods, is usefull know how a pinball works, I mean do you REALLY has to be a pinball player to know the interacction between mechanism, points, sounds, ligth, and other stuff. Also know BASIC programming and how to interfacing the Atari with external hardware. Also be good in handy work, (wood, soldering) and a lot of common sense. :D

 

Yes, I have more pinballs (without Atari inside hahahaha), they are Flash, Firepower, Gorgar, Supersonic, Space Invaders and Xenon. All from the 80's.

 

The problem with gas displays lies in the scanning. They has to be updated constantly (many times per second) and has I say before, Atari Basic is too slow for that kind of work.

 

PS: also have the Star Wars (data east) cabinet (without playfield). So I'm thinkg in the future. :-D

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flippers3.jpg

obra28.jpg

 

Soulbuster: some friends say me ¿why you don't allow to another guys to come and play? Paying for that. Well, you say the answer: playin hours on $1 makes me out of business. :D

Edited by ZZTOP SOFT

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zenti15.jpg

I buy components to build a final board for the score display. Yes, I know how make my own boards, but time goes by and I'm getting too lazy to do that way. :P

Edited by ZZTOP SOFT

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well, I definitely think this is a cool project. you might want to listen to any suggestions Fox-1 has, I think he once built a light controller (as well as a controller of other things) out of an 800XL for his car I think.

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