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

by Jon

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.