Arcade/console solutions

[tek909]

Hi guys. I like many have very little know how when it comes to programming and electronics but would like to trudge on and learn as I go to feed my geeky gaming habits.

I started this topic as a place where people (mostly noobs) can post questions and findings to slowly build some step buy step instructions that all can use to build emulation gaming systems of all shapes and sizes.


To get the ball rolling I have decided to build a mame machine. I am still waiting on my R-PI to show up but I am doing a lot of research in the hardware particularly using some arcade controllers and how to wire the dam things up. (I have delayed looking at the emulation as there are awesome programmers working on that as we …. type
This is what I have found so far although I am not sure if it will work with the R-PI

This article was a great start for an over view an lead me insome great directions.
http://www.maximumpc.com/article/featur ... c?page=0,0

from the article I found this as well which honestly I am not sure if it would be compatible or not. http://www.ultimarc.com/ipac1.html

I hope that this will be a lot simpler than the “keyboard hacks” I have been reading about.

so guys pls comment, ask questions, post tutorials, and share success stories. Pls keep it in the vein of helping others and try to avoid the arguing that you will find on a lot of forums. And remember there is more than one was to compile a digital cat… or something to that effect.

[bursar]

I have a couple of I-PAC4 boards that I used when building an arcade cabinet, and it basically works as another keyboard. The board comes with some software that let you configure the keys that get sent out when particular connections are made on the iPAC. The software then flashes this config info onto the I-PAC.

It looks like the linux version of that software is a third party creation, and I've no idea if it will run on the Pi. Having said that, if you have another machine available, you could change key mappings and flash it before attaching it to the Pi.

My boards have PS2 connectors on them, but I reckon they would probably work with USB adapters.

Phil.

[Daverj]

Arcade buttons and switch sticks would be simple to interface via the GPIO header. Analog joysticks would be a bit trickier.

[toxibunny]

I'd go for the gpio route too, personally. Then when you get everything set up, disable the USB for a 20% speed boost!

[bursar]

Will the GPIO cope with multiple inputs at once? It's entirely possible to need to register two directions (up and left) and two buttons (fire and bomb) all at the same time.

And if it's a two player design...

[tek909]

I am glad to see the replies starting to mount up. The info being provided is awesome !!!.
Thanks to Bursar for that detail as it cleared up some of the questions that have been mulling around in my skull.

Has anyone got any more info on how we can do this with the GPIO header particularly with the issues Daverj and Bursar raised of :

- how to sort out an Analog joystick
- how the GPIO will cope with multiple inputs at once.

Some other news on my own research is that I have contacted Andy from http://www.ultimarc.com/.
To my great excitement they are pretty keen to help out with this project.

Also on the web site is the u 360 http://www.ultimarc.com/ultrastik_info.html
Which has a built in 8 button interface which COULD make the need for the GPIO or an I-Pac style solution redundant? What do you guys think?

There is a fair bit of info about the U360 on the web site but some of you out there will probably have a better idea of its application on the R-PI

I will pass on the questions we have to them to see if we can get some more info on the hardware and get some further advise. I will also give them the heads up on this post so they have the chance to reply directly.

And thanks again for your input on this post guys, its got me pretty fired up !

[mahjongg]

analog joysticks were first used in the Apple ][, and the solution used there was copied to the joystick logic of the PC.
In principle its just a 555 timer configured as a "one shot" with the potmeter of the joystick, in combination with a 100nF capacitor, determines the one-shot time. The 555 is being triggered with a "strobe", then the time it takes for the one-shot to time out is read with a fast counter, in software, then the time (count) is directly proportional to the potentiometer setting. Often the same trigger signal triggers several 555's at the same time, and so you can read several potmeters at the same time. This principle can be done with the PI's GPIO's.

[tek909]

analog joysticks were first used in the Apple ][, and the solution used there was copied to the joystick logic of the PC.
In principle its just a 555 timer configured as a "one shot" with the potmeter of the joystick, in combination with a 100nF capacitor, determines the one-shot time. The 555 is being triggered with a "strobe", then the time it takes for the one-shot to time out is read with a fast counter, in software, then the time (count) is directly proportional to the potentiometer setting. Often the same trigger signal triggers several 555's at the same time, and so you can read several potmeters at the same time. This principle can be done with the PI's GPIO's.

is it possible that this sort of thing would already be included in the joystick (U360 as mentioned above) or is this something we would need to rig on our own and if that’s the case are you aware of a source where i can bring myself up to speed as to how i can do this.

Also in your person opinion do you believe that the using the GPIO’s as you stated, would be the way to go or would you lean towards using an I-pac or another keyboard controller or even another method all together.

Again i apologise for my lack of technical know how, but I appreciate the level of knowledge your bringing to the table.
technical know how

[tek909]

in addition to the above for anyone else like myself not up on the technical stuff on a 555timer, i found this wikki post which details the "one shot" config. http://en.wikipedia.org/wiki/555_timer_IC

[mahjongg]

analog joysticks were first used in the Apple ][, and the solution used there was copied to the joystick logic of the PC.
In principle its just a 555 timer configured as a "one shot" with the potmeter of the joystick, in combination with a 100nF capacitor, determines the one-shot time. The 555 is being triggered with a "strobe", then the time it takes for the one-shot to time out is read with a fast counter, in software, then the time (count) is directly proportional to the potentiometer setting. Often the same trigger signal triggers several 555's at the same time, and so you can read several potmeters at the same time. This principle can be done with the PI's GPIO's.

is it possible that this sort of thing would already be included in the joystick (U360 as mentioned above) or is this something we would need to rig on our own and if that’s the case are you aware of a source where i can bring myself up to speed as to how i can do this.

Also in your person opinion do you believe that the using the GPIO’s as you stated, would be the way to go or would you lean towards using an I-pac or another keyboard controller or even another method all together.

Again i apologise for my lack of technical know how, but I appreciate the level of knowledge your bringing to the table.
technical know how

The U360 is much more advanced than older potmeter using joysticks, and has all the interfacing electronics on board, and a microcontroller with USB, so you can use is directly without needing anything else.
The downside is that you need a suitable USB endpoint driver.

[khisanth]

I was thinking that if you can get a bluetooth dongle working, usb hard disk,some kind of script to auto sync and a small screen of some kind, then you could use the iCade as your case and controls.

[tek909]

hey all just an update on where i am at with this project. still waiting on my R-PI to show up which is a real shame as i am keen to get started. i have decided to try using the U360 via USB rather than trying to use the GPIO. mostly as if it works this will be a less scary option for your average joe. Will keep you updated as to my results.

[tek909]

my R-PI has finally arrived let the testing begin. Going to try something basic first, getting mame up and running then go from there.

[DexOS]

You need to make something like this but for the PI.
http://www.skpang.co.uk/blog/archives/152

Theres someone working on a bare metal GBA emulator for the PI.

[ajberry]

I was looking at buying the following:

http://www.ebay.co.uk/itm/ARCADE-MACHIN ... 416926edb9

Was wondering if anyone had any experience of using these with the Pi?

[khisanth]

Someone has recently got MAME up and running and hooked up an old competition pro joystick to the GPIO pins. Works perfectly!

[tek909]

You need to make something like this but for the PI.
http://www.skpang.co.uk/blog/archives/152

Theres someone working on a bare metal GBA emulator for the PI.

YESSSS! this is exactly what i am working towards. check the web site i posted further up in the thread where i will be getting all my hardware. in the end once wired up it should be plug and play via the R-PI usb.

[VanillaEssence]

Hey guys I figure I may be able to offer little help here. I built a stand up arcade from the instructions provided on this great website that offers a range of different pieces of information about MAME cabs: http://www.koenigs.dk/mame/eng/
As for arcade sticks ozstick.com.au are the Australian reseller of Ultimarc. I bought from them and it shipping was really quick and the product results were fantastic I'd definitely recommend them. If you do go with the I-PAC you'll find wiring is surprisingly simple. I am unsure of the compatibility of the Ipac with the Rpi but with any luck I'll be able to check it in the coming weeks if my Pis arrive.

Hope I was of some help,

Hamish