Building the Picade Mini Part II, new screen!!!

In the first part of this build, I got the majority of the main cabinet together, but I stalled out when the LCD refused to output correctly. The guys at Pimoroni finally identified that the LCD driver board had a bad firmware on it. A few emails later and a new board was on its way.

Testing the Picade Mini's new LCd driver boardThe hardest thing was getting the new driver board in place in the tiny space of the cabinet. I ended up removing the whole screen assembly from the cabinet to make life easier.

Installing the new LCD driver boardReplacing the board involved popping off the old one (pinching the little plastic pins that held it to the back of the screen) and disconnecting two ribbon cables- one large one for the screen’s control panel, and one tiny one that connected the board to the screen itself. Then I replaced the old board with the new one, reconnected the cables and powered up the screen.

A couple things to note. First, the thin ribbon cable from the board to the screen has to be in perfectly or the screen won’t work. You can’t just jam the cable in there (as I tried). There are two tiny little tabs on the edges of the board’s connector that must be pulled out so that the cable goes in easily, then pushed back in to pinch the cable in place. Secondly, by default the screen is set to go to sleep after 15 seconds of no signal, and you must have a signal in order to use the OSD menu. So if you want to play around with the screen’s settings at this point in the build, you’ll need something to display connected.

Installing the marqueeAfter I’d tested and reinstalled the screen, the next step was to go back and finish off the top of the cabinet, namely the marquee. This began probably the longest part of the evening because all of the tabs and slots for the top of the cabinet didn’t fit together nicely- I had to take sandpaper and a file to everything and still ended up forcing some bits in.

Testing the joystickOnce I got the marquee on and the top bolted shut, the build finally started to feel solid. Next was to fasten down the main control panel, but since I’d popped it in and out so many times while fixing the screen (and to clean out sawdust), I first decided to power up the controls and verify that everything was still working as expected.

Installing the control panelInstalling the control panel was much a repeat of the marquee, ie. none of the tabs fit quite right. It’s expected that you have to squeeze the cabinet a little to get the control panel on- you don’t want anything popping off in the middle of a game, but it was still more work than I expected.

Testing the controlsAfter getting the controls bolted on, it was back to testing. Namely I connected the Picade PCB direct to my laptop and verified that all of the buttons reported correctly and reliably.

Testing the connections againConfident that the buttons were ready to perform, I skipped ahead and installed the LCD’s control panel onto the side of the cabinet. I don’t intend to actually use it much- I want the screen to come on right when I hit the main power, and stay on until I shut down the machine. I don’t want to fiddle with any screen settings on this any more than I want to on any other device.

Testing the screen controls with the screen onA word on the screen buttons themselves- clever idea, with the acrylic buttons on top of the little buttons, but in my testing there was an inconsistent feel to them. I connected the screen to my test RasPi and while the power and input select buttons give a good solid click, the others feel mushy. I might need to fiddle with them a little more, but as I said, since I don’t plan on using them much anyway, it’s not my top priority.

Well, that’s it for this stage of the build. Picade Mini, looking good from the frontI have what’s amounting to a pretty nifty little arcade machine going on here, and as far as what the kit offered, I’m just about done. According to the kit all that’s left is installing the rear door, which I’ve skipped for now, and connecting up a RasPi. So now is where the fun really begins – though I still intend to mount my RasPi to the back door, I also want to make some major usability modifications first. Namely I want to install externally facing USB, Ethernet, headphone, and power jacks into the door, as well as a single physical power switch.

A single power switch with a single power supply means a more creative wiring system than hiding a bunch of wall-warts inside the cabinet. I also plan on adding a powered USB hub in there, which I’ve already rewired in advance to not draw power from the little RasPi. Basically I think I have all the pieces I need and I know how to wire it up- the main issue now is deciding where and how to mount everything.

But we’ll have to save that for next time. Stay tuned!


P.S. Big thanks to Jon at Pimoroni for getting me that replacement board so quickly. Despite all the nervousness one might have about the Kickstarter model, I’ve been thoroughly impressed by the turnout of this kit.

Update (02/10/14): Part III is up!

Update (03/05/14): See the video: Picade Mini build running RetroPie.

Building the Picade Mini Part I

It was over a year since the Picade Kickstarter ended that I finally got my Picade Mini kit in the mail. Others have reported some issues with these early kits, but with the holidays I wasn’t able to crack open my box until this weekend.

Picade Mini PanelsFirst up let’s take a look at the instructions. We have a bunch of very nice wood panels and a system of plastic wedges (fixed joints) with bolts and nuts to hold everything together.

Picade Mini BottomHere’s what the bottom looks like with the plastic wedges bolted on. Notice the edges of the board, which feature a jigsaw puzzle-like pattern for connecting them to the other boards.

Picade Mini Bottom and SidesNext I’ve attached the side and front panels, and it’s starting to look like an arcade machine already! This is going to be a quick build at this rate.

Picade Mini with the screenThe instructions call next for the screen, so I go ahead and pop that in. But before I get ahead of myself, I know that others have had problems with their screens, so I go ahead and plug it in to see what’s what. And sure enough, my screen outputs double- the whole of the input is mashed up at the top of the screen, with it repeated at the bottom. Damn.

Undeterred, I continue forward with the instructions and decide it’s high time to build the controls. I pick out the design to go under the acrylic and install the joystick and buttons to the control board. Everything pops in pretty easy, and now it’s time to see how this thing mounts to the rest of the cabinet.

Dremeling away the fixed cornerHere I run into my next issue: there’s another set of plastic wedges for securing the controls, but as other builder have discovered, the right-most buttons interfere with the placement of the wedge. So, looks like I need to grind down that wedge a bit- what better a time to test out the new Dremel I got for Christmas.

Reshared wedge under the control boardI make a couple quick marks on the wedge with a pencil, then out on my patio in the rain (hey, it’s Seattle) and away we grind. Not ten minutes later, and the modified wedge fits perfectly!

Picade Mini control panelFlip the panel over, and it looks great. There’s a variety of colored buttons in the kit, two each of red, blue, green, and yellow, along with four black, and a red ball on the joystick. At first I can’t decide on a scheme I like, but then I dig into my stash of joystick parts, and come up with a white joystick ball and decide to mimic the Xbox 360 controller with my layout (I am an Xbox guy after all).

Picade Mini with the control panel onSince the screen will probably need replacing, I can’t bolt it in permanently, and I can’t finish up the top marquee just yet. But even without it, it looks good with the controls and the other cabinet buttons installed.

I move on to the wiring, which is a pretty straight forward affair of connecting all of the buttons and the joystick to the Picade’s custom PCB, and installing the speakers on the inside of the cabinet. Others have reported problems with the wiring looms, and to be sure I test them all first, and end up fixing just one crimped connector in the whole set.

Picade Mini broken screen 2Then I plug the PCB into my laptop, and sure enough, it appears as an USB keyboard. By default the joystick reports as arrow keys and the buttons as the default controls for MAME. Unfortunately this means unnecessarily using the Control, Alt, and Shift keys, and I don’t want to enter some command by mistake (on the full-size Picade, you can hit Control+C by hitting two buttons at once, which would be an annoying surprise in the middle of a game). So following the instructions of others, I fire up the Arduino IDE and reprogram the buttons to my liking.

Picade Mini broken screen 1 But now I’m little stymied. I could go forward on several fronts, but it’s already getting a little cramped in the cabinet and with the broken screen I don’t want to put too much in the way before I replace it. Once the double screen gets fixed though, the cabinet should be easy to finish off. I just need to attach the control board, the top marquee, and finally the back door.

After that, I can start focusing on the brains of the machine, and the further customizations I have in mind. Stay tuned!


P.S. Since the creators of the Picade got lots of extra backing money, I think they overgeneralized the design- great for folks who don’t want to actually use a Raspberry Pi themselves, but not so great for those who do. Namely, they don’t address the Pi’s missing power switch, which in my experience with emulators means that without a keyboard on hand, if a game freezes and you hard power down, the Pi’s SD card gets corrupt and you can’t boot anymore.

There’re plenty of 3rd-party hardware solutions to this well-known problem, and it’s a little disappointing that the Picade guys didn’t integrate one into their design. Also, you have a power supply for the monitor alone, with the expectation (in the instructions) that you need to add a separate power supply for the Pi, then inelegantly run two power lines out the back, or hide a power strip inside. That’s another thing- by default you either have to run out any cables (say network and USB) out slots in the back, or keep opening the back door to access anything.

With all that in mind, I’m going to install my own Ethernet and USB ports, as well as a power jack and an actual power switch, a single one for a single power supply that powers the whole cabinet. Overall, I think I’ll end up with a pretty sweet machine if I can get the screen replaced, but this project is definitely not the “just supply the Raspberry Pi” weekend project I thought it’d be.

Update (01/23/14): Part II is up!

Update (03/05/14): See the video: Picade Mini build running RetroPie.