Need some advice re: a potential mini racer cabinet project idea.

[MrThunderwing]

I bought one of these Thumbs Up Retro Racer mini cabinets awhile back with a gift voucher I got from my work. The games on it look and sound about the equivalent of something you'd find on the NES, but are really all just utter trash. It's got a nice little steering wheel on it though and I keep getting notions in my head about whether it'd be feasible to take it apart and stick something like an ultra small form Raspberry PI in there, and re-using the existing controls and the screen it comes with. The only problem being, I'm clueless about any kind of electrical hacking and soldering type stuff. I hooked up the Xin-Mo 2 Player Arcade Controller Interface on my Barcade about 6 or 7 years ago, so I've a vague notion of how arcade controllers and daisy chains and that work from back then, but that's about it.

What I'd really like to know, is if I can hack the controls on this thing to work like a regular PC joypad. I haven't looked inside it yet, but I'm 100% certain there's no analog steering involved, the wheel's just moving left and right like a digital d-pad and that's all I'd want to replicate, so I'm not looking for anything complex involving potentiometers or anything like that.

If it's just working on the same principle of a regular joypad, of closing a circuit when a button is pushed, could I just cut whatever wires the wheel's attached to inside it control-wise and solder them to the left and right function on a cheap (and small) USB joypad instead? Or do I need to look at getting something like an ipac arcade encoder to connect it up to? Is that even possible for something like this? (I know I'm asking a lot of questions for something I haven't even looked inside yet - I'm thinking hypothetically here...)

I had a look at the tutorials in the main section of the site, but I couldn't seem to find any info on this very specific thing I'm thinking of - specifically using the controls and buttons already built into the machine on a PI. Can anyone here suggest any helpful videos or tutorials or just provide some general advice? I'm not too worried about the the feasibility of re-using the screen 
at the moment, really I just want to figure out if re-using the existing controls is possible first.

Thanks in advance for any responses!

[baritonomarchetto]

Even is it's not your main concern at the moment, interfacing the monitor has the potential to be the most difficul part. I see no reason connecting those switches to a raspy GPIOs should be a problem.
Is a raspy going to fit in there?

[vandale]

Don't use the existing screen, just buy a cheap china lcd. Also you could use a intel stick pc allowing you to run M2 emulator. Then some Daytona art and your done.

[MrThunderwing]

Wow, I didn't even know stick PCs were a thing! That definitely seems like it would potentially be an easier solution than a PI (which I don't really know anything about). I was fully thinking I'd probably need to completely swap the screen out.

I've actually already decided on an Outrun theme for it and designed some artwork based on the standard upright to fit the mini cabinet's form factor - you can see some black and white mock up pics attached (the colour jets in my printer died ages back). I'm currently waiting on some colour vinyl sticky back plastic versions to arrive in the post. My original plan had just been to dress this cheapo mini cabinet up like an Outrun and that was it, it wasn't until  I got properly into the design bit I started to think about ACTUALLY modding it to play some MAME stuff.

[BadMouth]

Years ago I bought a similar looking non-racing mini arcade cab from a clearance bin with hopes of making a tiny MAME machine.  I had a Pi zero with retro-arc installed & a Kade encoder ready to go.  The screens were more than I wanted to spend on a novelty, so I abandoned the project.

Don't do it if you're not going to do analog controls.  Racing cabs suck without analog controls.

If you do it without analog controls anyway, limit it to Sega Genesis ports of the games since they were designed to be played with digital controls.

Pretty sure you'd have to solder or at least crimp the connections to the controls interface at a minimum.

[BadMouth]

It turns out that I actually made a project thread for that mini cab:http://forum.arcadecontrols.com/index.php/topic,152580.msg1597351.html#msg1597351
The project was abandoned and the picture quality is horrible, but there might be something of use there.

[MrThunderwing]

Thanks for the link to your project BM. I was thinking of just sticking with digital controls initially as I wasn't planning on having anything more advanced than MAME in there and I've found (from playing some 2D racers on my phone) that stuff like Outrun and Chase HQ play ok-ish like that, using my 8BitDo Zero 2 Wireless Bluetooth Gamepad Controller. Obviously, stuff like Daytona and Outrun 2 wouldn't be good.

I think I'm going to need to have a think about how advanced I'm prepared to go with this. I've got a mate who's electronics and soldering savvy, who's arm I've managed to twist into working on this with me. He also knows about PIs and MAME which is handy. Small form PI with some kind of hacked digital USB joypad and a cheapo mini screen with the intention of just 2D stuff on MAME was really all I was originally intending.

Hooking up an Arduino with a potentiometer seems like it would be the way to go forward if I wanted to turn that mini wheel into a bespoke analog device. But will whatever custom software I need to run that work on a PI? Stick based PC could be the way forward there, but this increases price substantially, but does open up the possibility of adding Model 2 Emu on it... But if I wanted to play Daytona properly, I'd need to add in a load of extra buttons.

Also, space inside is going to be very limited. I'm assuming cheapo 2.5 - 3 Inch monitors don't do sound, so I'm probably going to need a teeny weeny sound bar to fit in there... Plus, I know I'll want to light up the Marquee somehow too. Maaaaybe even look into MAMEhooker for some output lamps...

So, yeah... A bit to think about there...

Edit: Oh and Vandale's totally got me into the idea of some Daytona art to fit the cabinet. I've bought a second one off of Amazon (only £18). Even if I don't do anything with the innards, I might just dress this one up like a mini Daytona. I've already made the art now. I'll probably spray it black. I might have a go at some fake mini T moulding with some epoxy putty and try to make a tiny cardboard bezel.

[MrThunderwing]

Here's 2 different Daytona mini upright side art designs i've come up with. I've tried to keep the main aesthetic of the Daytona sit down cabs, but used a bit of artistic license. Which one do you guys prefer? Option 1 on the left or or option 2 on the right?

[Mike A]

"stuff like Outrun and Chase HQ play ok-ish like that"

Is that really the bar you want to set for game play?

I don't get it.

[MrThunderwing]

Well, nothing's set in stone yet, but I wouldn't have a problem with that particular bar: it's a tiny device, it's really going to be more of a novelty than something I'm going to be pouring hours of gameplay into. OK-ish was probably a bad choice of phrase - they play fine with digital controls.

[vandale]

"stuff like Outrun and Chase HQ play ok-ish like that"

Is that really the bar you want to set for game play?

I don't get it.

Its a novelty toy the size of your mum's dildo, its not a driving sim.

[Mike A]

I always try to set the bar high.

Even on a novelty project.

You might just want to play some kind of video of gameplay on the screen if it is a display piece.

That would greatly simplify the project.

Hacking together controls that small that still function reasonably well might not be worth the extra effort.

Whatever you decide I will watch and offer help if I can.

Oh, and vandale, If you don't like that then keep your insults directed at me, not my mother, who is the best person I know.

[MrThunderwing]

So I disassembled the mini racer cabinet today. The controls are connected up to a separate circuit board than the main game. It very handily tells you the name of each input and identifies their location in relation to the ribbon cable that attaches up to it. So, my new plan for this, is that rather than ---smurfing--- around with a PI or a stick PC and trying to figure out how to connect it to a tiny screen (which seemed far more complex than just the plug and play option I was expecting, for the really small HDMI less screen) and also getting a tiny sound bar in there, I've thought of an all in one budget friendly solution! A refurbished secondhand Android phone running MAME4DROID - it's got everything I need ready to go; screen and sound working out the box, a built in rechargeable battery and an easy to install version of MAME. I've tested it out using my own phone sizewise and it (more-or-less) fits, with the portrait version of MAME's screen appearing in just the right place for the screen (the pre-existing monitor bezel's a bit too small, but I can easily enough make a new one out of an old CD case with my Dremmel). I've got a tiny Bluetooth joypad that I can use on my phone - so the plan is to figure out a way to hook up to the existing mini control panel, so I can play this with the tiny steering wheel. My electronics savvy friend and I are going to have a think about what the best option for that would be.... So, for a not too dissimilar price to a PI, screen and soundbar, I've got a refurbished secondhand Samsung phone winging it's way to me in the post from eBay.

I bought multiple copies of the art I created for it from the printing place, just so I had plenty of spares if I messed up the application of the stickers. I decided to test one out to see what it looks like in place (I haven't properly applied the side art, it's just temporarily held in place with blu tack). I think it's turned out pretty well. I think I going to need to spray paint the cabinet black though to match the real life Outrun upright.

[MrThunderwing]

Outrun 2

[BadMouth]

Sweet!   Was not expecting leaf switch steering...

I do recommend usb input instead of bluetooth if you can find a device and fit it.  The lag is night and day, at least on my phone.

[MrThunderwing]

The only issue with that though, is that the usb socket's going to be in constant use with the power cable attached. I find the Bluetooth connectivity fine myself.

[buttersoft]

That was fast! And a really nice result, too.

[MrThunderwing]

Cheers mate, this is still very much WIP - this was me just checking that a phone running MAME would give the sort of result I was after and that I could get the screen in the right place. The actual phone that's going to sit inside it isn't with me yet, once it arrives, there's a few screw posts and bits and pieces inside I'm going to have to remove. I'm also going to have to make sure that whatever control panel solution we come up with can still fit inside.

[MrThunderwing]

Some (very) WIP test footage. It's literally just me lying my phone inside the empty shell of the cabinet, but it gives you an idea of what it should, hopefully, eventually end up like. With a bezel that's not too small in the finished article, hopefully I'll have some wriggle room with that bit of phone that's poking out the top (although, this isn't the device that ultimately's going to be used), or maybe I might need to make a small additional base to let it fit a smidge better. If I still end up with a bit of phone poking out, I'm sure I can dress it somehow to look like it's part of the cabinet.

[BadMouth]

The only issue with that though, is that the usb socket's going to be in constant use with the power cable attached. I find the Bluetooth connectivity fine myself.

Not pushing it if you are happy with bluetooth, but the solution to that issue would be an "OTG" cable with separate power.  It's basically just a cheap splitter/adapter for the usb port.  They also make them with full size USB-A on one lead which an encoder or gamepad pcb could plug into.

[MrThunderwing]

Thanks BM, that's useful to know - good to have more options.

Something that popped into my brain during the night (literally - was just getting up for a pee around 4am and this thought, totally unbidden, just materialised in my brain and then kept me awake), was how to actually access MAME, once the phone's in the case. There are arcade front ends for Android, but I don't know if they can be set to auto start when the device is powered on, like I've got Maximus Arcade set to on my Barcade, and with the bezel in place I can't use the touchscreen. Fortunately technology had my back here and a simple voice command of "Hey Google, run MAME4DROID" started it up hands free. Groovy. If there's a Front End way of doing this, that'd be great, but it's good to know I can access MAME without physically having to get to the phone screen (and this is assuming the cheaper phone I've ordered from eBay can do all the stuff my regular one can)

[MrThunderwing]

The refurbished secondhand Galaxy J5 from 2017 arrived in the post yesterday. I've got it setup with MAME and stuck a load of old school racers on there and a GBA emulator (for the handheld F-Zero games). It's nowhere near as powerful as my actual phone (which secondhand goes for nearly 4 times the cost on eBay as the Galaxy), so it struggles with Outrun 2 Coast 2 Coast on PPSSPP and Daytona USA 2001 using RetroArch. It isn't quite powerful enough for Outrunners on Sega's System 32 board either. Really bizarrely, it struggles a bit with the original Outrun, but it handles all the other 2D Sprite scalers from that time with no problem: Chase HQ, Super Hang-On, Super Monaco GP, Cisco Heat, Racing Hero all play full speed, but the original Outrun has stuttery audio without the frame skip option on. It's weird, because Super Hang-On, Super Monaco GP and Racing Hero are all on later, more powerful Sega boards and Chase HQ came out 3 years after Outrun, so I don't get why the phone's struggling a bit with the older game (in all it's different ROM incarnations...). It's playable with frame skip and the audio gets sorted. The loss of smoothness is barely noticeable, but it bugs me that I can still see it...

I found a frontend for Android called DIG which can be set to auto start on power up, so that's cool. With the bluetooth controller powered on, I can get past the power on lock screen at the touch of a button. The actual physical power on button is located on the side of the phone and it looks like it would be an absolute nightmare to try and figure out a way to hook up an alterantive on/off switch to the plastic case of the cabinet. I think some sort of hinged door that allows access to it might be a simpler alternative.

My sodding Dremmel died when I was having a go at cutting out a new marquee... Alas, not simply a blown fuse in the plug.

[MrThunderwing]

OK, so trying to get the current mini-cabinet controls mapped to the 8BitDo Zero 2 Bluetooth Gamepad with a bit of soldering looks like it's going to be too problematic. So plan B is to try and hook them up to an arcade encoder that'll work on Android. Apparently the Zero Delay Arcade Encoder is Android compatible (so looks like I'll probably need to use an OTG cable as suggested by Bad Mouth).

I need some advice on wiring here though. As I mentioned in my initial post, I'm familiar with the concept of how to wire up arcade buttons to an encoder and daisy chaining them to each other and  the ground. As far as my understanding goes, a PCB is doing the same thing, with the rubber contact pads of a joypad closing the circuit rather than the arcade button. The Retro Racer mini cab's PCB actually tells you what button does what and there's a ground wire too. The Zero Delay doesn't seem to have a ground labelled on it, so how would I go about wiring that in? (Also, each wire in the ribbon cable for each input is singular, so how do they get grounded? Something on the PCB itself connecting them up?)

Any advice gratefully received, cheers!
(Link to the encoder on Amazon: https://amzn.eu/d/3Iu9Vxh )

[PL1]

I need some advice on wiring here though. As I mentioned in my initial post, I'm familiar with the concept of how to wire up arcade buttons to an encoder and daisy chaining them to each other and  the ground. As far as my understanding goes, a PCB is doing the same thing, with the rubber contact pads of a joypad closing the circuit rather than the arcade button. The Retro Racer mini cab's PCB actually tells you what button does what and there's a ground wire too.

I don't see any components like diodes or capacitors on the mini cab's PCB, just the leaf switch.
- Assuming there are no components hiding on the back, your understanding is correct and it should be easy to connect the mini cab PCB to the ZD encoder.
- The ribbon cable input pins are connected to traces (narrow light green parts of the PCB) that lead to one side of the switches.
- The ribbon cable ground pins are connected to the backplanes (wide light green parts of the PCB) that lead to the other side of the switches.  The backplanes are like a daisy-chain ground wire in normal arcade wiring.

WARNING: Ensure there are any no ground connections/wires to the PCB other than the two "GND" pins on the ribbon cable before connecting this PCB to the ZD encoder.  If there is another ground connection/wire to the PCB, the mod described below will short 5v to ground. 

The Zero Delay doesn't seem to have a ground labelled on it, so how would I go about wiring that in? (Also, each wire in the ribbon cable for each input is singular, so how do they get grounded? Something on the PCB itself connecting them up?)

Most ZD encoders are "active high" devices. (5v triggers the input port, not ground)

As you can see in this pic, the outer pins on the ZD are daisy-chained together via the outer backplane of the PCB.
- The outer backplane/pins are almost certainly providing 5v.  It wouldn't hurt to verify this with your multimeter.   
- When you press a button, the 5v from the outer backplane/pin is applied to the inner pin which is connected to the input port.  5v on the input port triggers the associated output.



Since the mini cab's PCB doesn't have any components like diodes or electrolytic capacitors on it, you can connect it to the ZD encoder.
- Connect one outer pin on the ZD (daisy-chained 5v) to one of the GND pins (daisy-chained grounds) on the mini cab PCB ribbon cable.
- Connect a different outer pin on the ZD to the other GND pin on the mini cab PCB ribbon cable.
- Connect the inner pins of the ZD (input ports) to the desired pins on the mini cab PCB ribbon cable.


Scott

[MrThunderwing]

Thank you for the extremely detailed reply PL1, it's greatly appreciated. So, just to make sure I'm understanding you correctly here, I'd be looking to wire up the ground pins like in the (crudely doodled on my phone) attachment?

[MrThunderwing]

One other question: I notice the ZD's got these two separate "Power 5v" pins - will it need an external power source from somewhere or will just plugging the USB cable into the phone suffice?

[PL1]

So, just to make sure I'm understanding you correctly here, I'd be looking to wire up the ground pins like in the (crudely doodled on my phone) attachment?

You got it.  Mini cab PCB daisy-chain to encoder daisy-chain.   

One other question: I notice the ZD's got these two separate "Power 5v" pins - will it need an external power source from somewhere or will just plugging the USB cable into the phone suffice?

Those red "Power 5v" connectors are power outputs for LEDs IIRC.

Plugging the encoder USB cable into the phone is the only thing you need for power.


Scott

[MrThunderwing]

Brilliant, thanks Scott 

[BadMouth]

Do you already have the zero delay encoder?

I would think there should be something out there with a smaller form factor and better usb connector type. Maybe PL1 can say if there is a current kade equivalent.

You might also look into the raspberry pi pico.  They are only $5.  I am assuming there is a premade image out there to use it as an encoder and that it will work with android.  It will also do analog if you decide to add it later.

[PL1]

I would think there should be something out there with a smaller form factor and better usb connector type. Maybe PL1 can say if there is a current kade equivalent.

If someone wants a small form-factor Arduino for a project like this, a Pro Micro (0.71" x 1.4" + micro USB connector length) is a great choice.
- There are plenty of inputs and, like the Ras Pi Pico, the KADE miniArcade 2.0 firmware can handle analog inputs. (potentiometers)



- If you want to insulate the Pro Micro, 3d print a case like this one.
https://www.thingiverse.com/thing:4295684


Scott

[MrThunderwing]

I've already got the Zero Delay on order from Amazon - I just went with it as it's apparently Android compatible - form factor-wise it doesn't seem too big in the pictures, so I think it should be OK... 😬

I think, on reflection, deciding to use the Android phone for this was really creating a bit of a rod for my own back. If I were to do it again I think PI Zero 2 would be the way forward (unfortunately though, they don't seem to be in stock with regular retailers in the UK and are only available on eBay and Amazon from scalpers for 4-5 times their normal RRP. I ---smurfing--- hate scalpers...)

Just out of curiosity, Is that Pro Micro Arduino something that needs some programming ability, or are they plug and play?

[PL1]

Is that Pro Micro Arduino something that needs some programming ability, or are they plug and play?

With the KADE MiniArcade 2.0 Mapper program you don't need any programming skills, just the ability to read/follow the detailed directions in the User Guide to select the desired settings and upload the firmware to the Arduino.
- There's an Arduino-specific section of the User Guide with all the details you need to know. 

Once you do that, the Pro Micro will appear as a USB HID keyboard or a USB HID gamepad.



Just re-uploaded the Windows version of the program to Sendspace and updated the link in the first post in the MiniArcade 2.0 thread.
- The User Guide is in the "docs" folder if you want to check it out.
https://www.sendspace.com/file/y5yc5x
http://forum.arcadecontrols.com/index.php/topic,154126.msg1615622.html#msg1615622


Scott

[buttersoft]

The Arduino Pro Micros are great. Many ppl here will be able to help you troubleshoot. The pi pico is even better for windows but i'm not sure about adroid gamepad firmware. It might just work, IDK.

[MrThunderwing]

OK, thanks fellas, good to know!

A quick question about aesthetics - This is purely subjective, but I'm just curious what other people think here....

I'd been thinking about spray painting the mini cabinet black to better match the look of the original Outrun stand up cabinet, but I think I actually quite like the red cabinet with the black bordered monitor (a red cabinet seems kinda in keeping with Outrun's red Ferraris). The original Outrun stand-up had a grey monitor bezel with the route map under the screen, that did that kind of indented thing so the CRT is sunk back a bit in it (I can't think what the correct term for it is). I've removed the original bezel from the mini cabinet and cut almost all the plastic back underneath to fit the new one I've made, just leaving a centimeter or so of the original plastic to adhere the new one to. The phone screen takes up most of the display, so when I mask off the bezel and paint it, the painted edges will literally only be a a centimeter or so, so no room for the route map and it will obviously be just a flat piece of clear plastic, without the indented effect.

So, my question is this: Do you think a flat, grey edged bezel will look a bit crap? If I spray the cab black and the edges of the bezel black too, is it going to be too much black? Do you reckon I might be better off just leaving it red and the bezel edges black (like the original bezel it came with). Thoughts?

[BadMouth]

I like the red.  If it ain't broke don't fix it.
Not sure about the bezel.  I'd have to see it.
EDIT: After looking at some pics, I say black bezel.  It leans more toward the sit-down cabs, but I think the color scheme (outside of the artwork) on them looks better.

[MrThunderwing]

Thanks BM. I'd pretty much talked myself into just leaving it red, good to get an additional perspective on it.

[Howard_Casto]

Patiently waiting to see how this turns out.   Out of curiosity how old and busted can a phone be to still run android mame at a respectable speed?   I've got some phones lying around but they are super jank... like tracfone jank.   

[BadMouth]

Patiently waiting to see how this turns out.   Out of curiosity how old and busted can a phone be to still run android mame at a respectable speed?   I've got some phones lying around but they are super jank... like tracfone jank.

The MAME4droid on my phone is based on MAME V.139.   There are other ports of MAME out there based on v.32.  So it's very much like a PC.  If it won't run full speed, try an older version.

[MrThunderwing]

Progress is on a little bit of a hiatus at the moment, until the encoder arrives, which Amazon is telling me will be around mid-March time. One tiny little thing I've done is paint the 'pedals' with some old silver enamel paint I had lying around and then gave them a quick wash with some watered down black acrylic, to make them look a bit more metallic rather than cheapo red plastic. I also painted up the gear stick black and silver and the top row of buttons light green (to match the Outrun start button).
The OTG cable I bought off Amazon arrived a few days ago and I was able to get a wired PC controller working with no hassle on the Android phone (literally plug n play). Having a cable plugged into the bottom of the phone makes it a bit too big for the case. I've got a very small right-angled micro USB extension on order from eBay, but if it's still too big with that, I'm probably going to need to cut a hole in the bottom and just add an additional base to the cabinet that's just a few centimetres or so.

Howard, MAME4DROID took me literal seconds to setup. I wasn't aware there were different versions (as BM mentioned), but the one I got from the Google play store just needs to install then you just direct it to your ROMs folder and you're good to go! Probably worth just giving it a shot on your old devices and seeing what results you get.

[BadMouth]

Looking good.   
Steering wheel needs a black on yellow Ferrari logo in the middle if you can one for a buck or two.  Doesn't have to be a circle.