1. Overview

Plan your build

Before we started building our RaspCade, we thought carefully about what we would need and how we could keep it simple. We used a LCD screen that we already owned, but any 7 inch screen should fit! The trickiest part was designing the cabinet, but this should now be as simple as downloading the files and getting them cut by a laser cutter. The parts list is not set in stone, but pay attention to dimensions as the cabinet is designed with ours in mind, particularly the buttons and panel mount parts!

Download the RaspCade Designs

To save you the hassle of making your own cabinet, why not download our designs here: https://www.raspberrycoulis.co.uk/download/472/ The designs have been optimised for use with online laser cutting services, such as RazorLAB (Ponoko to our US readers) to keep things simple! Plastics require special solvents for this and can be quite messy, so 3mm MDF is recommended when cutting because it is cheap and easy to glue together once assembled. If you want to tweak the designs to your liking, then you will need Adobe Illustrator as they are saved as EPS files.

Don’t overcomplicate things!

As this is a DIY build, we highly recommend you keep things as simple as possible - at least for your first attempt anyway! Arcade machines nowadays are full of flashing lights and enticing sound effects. Whilst this would be awesome, replicating this at home might be challenging. However, if you are feeling adventurous, then go for it! For example, in our build we are going to add Neopixels driven by an Adafruit Trinket, and held by custom 3D printed mounts within the clear arcade buttons, but you do not have to do this if you aren’t feeling confident.

Here’s what we’ll be using

There are many options for emulation software to use on our RaspCade, but we’ll be using RetroPie in this build. RetroPie is very easy to setup and provides a fantastic front-end to our RaspCade. It is always being refined and updated by the developer, plus it can play a wide variety of games, so it makes an excellent choice for this project. You can download the latest version of RetroPie here: https://retropie.org.uk/download/ Due to legal reasons, this guide will not give information on downloading ROMs, but there is a lot of information online about this already.

Want more? Then experiment!

If you are reading this thinking “Why are there only 8 buttons instead of 10?” or “I want flashing lights all over the place!”, then feel free to give it a go yourself. You do not need to follow this to the letter. As we have said earlier, the cabinet design is based on the parts we have available but if you are feeling creative, feel free to design your own cabinet or tweak the one we have designed. We would love to see what you do with your build and hope you share them!

Ok, I’m ready! What’s next?

Now it’s time to get all your parts so that you are ready for the next stage. All ours were bought online, through Raspberry Pi distributors and eBay. Costs may well vary but you should be able to find everything you need. In the next edition, we’ll start building our controls. For this you’ll definitely need the joystick, buttons, the arcade wiring harnesses and the PiCade PCB. We will cover the basics of wiring up all your buttons, including the joystick, and how to use them with the PiCade PCB for a hassle-free installation.

2. Controls

Plan your wiring first!

Before you put your controls in place, it is worth doing a test run first. Connect your wires and be sure you understand what goes where before placing them in your cabinet. The arcade wiring harnesses are perfect for this as the spade connectors simply slide on (and off!) the buttons, so no soldering is required! Each button (including the joystick) has a positive and negative terminal. You can ‘daisy-chain’ (connect together) the negative terminals, which means you only have one ground wire instead of several! Once you’re happy, carefully press the buttons into place - they are a tight fit!

Bolt your joystick in place

If you’re using our arcade cabinet design, the four holes should line up with the mounting plate on the joystick. Unscrew the ball-top and slide off the plastic collar and then bolt the joystick in place using four M4 screws and bolts. You can use a countersink drill bit to tidy this up if you like, but don’t worry if not. Also, do not over-tighten the bolts as this could damage the cabinet. Once you have done this, pop on the plastic collar and screw the ball-top back on. Now onto the wiring underneath...

Better get yourself connected!

Connecting your controls is not as difficult as you may think! Grab your 4.8mm arcade harness and slot one onto each negative (black) terminal. Daisy-chain them so you have one wire connecting the four negative terminals. Once done, use some wire cutters to cut and strip the end so you have a wire that can be connected to the PiCade. You may need to extend this wire, but this can be done easily even for a soldering newcomer. Next, connect one wire to each of the positive (red) terminals - each of these will be connected to the PiCade too.

Push the button

Before wiring your buttons, carefully push them through the holes in the cabinet. They are a tight fit so be gentle where you push to avoid snapping the cabinet! Once in, use the 2.8mm arcade harness and daisy-chain all the negative terminals (any can be used, but use the same one on each button) and strip the end again. Then connect one to each positive terminal so you end up with seven wires ready to connect to the PiCade (Six positive and one negative). We can now move onto the final two buttons on the front panel.

Assembling the front panel

The front panel consists of two arcade buttons, a USB port and the headphone jack. The buttons pop in place the same way the others, and you also need to daisy-chain the negative terminals - you should have three wires (two positive and one negative). The USB port screws into place and the other end will be connected to our Pi. You can use this to connect a WiFi dongle, or a USB thumb drive to store all your games, making it simple to add more. The headphone jack screws into place, allowing you to play your RaspCade without disturbing everybody!

Connecting to the PiCade PCB

Connecting all our wires is dead simple thanks to the PiCade PCB! This has several screw terminals, all nicely labelled for our arcade controls. Simply find the relevant terminal and then screw the wire into place. You should have 8 wires for the buttons and 4 for the joystick, as well as 3 ground (negative) wires. It isn’t essential to put the wires in exactly the right place, so if your ‘up’ button is connected to the ‘down’ terminal, it can still be configured once in RetroPie. The PiCade simply connects to the Pi via USB and that’s it!

3. Display

The screen

The screen we are using was part of a now discontinued case for the Raspberry Pi called the Qubit. It is a 7-inch IPS screen with a maximum resolution of 1024 x 600 and looks fantastic when up and running. If you are looking for the same screen, then look on eBay for a 070-FPCA-R1 screen and you should find plenty. However, you can use any 7-inch screen as our cabinet has been designed to accommodate screens of this size. Just remember that you will need a HDMI LCD driver board to make your screen work though!

The HDMI LCD driver board

The driver board makes the screen work properly and allows you to connect it to your Pi. Our screen uses the PCB800168 HDMI LCD driver board, which can be found on eBay, although it did come with the Qubit case. The screen connects to the driver board using a 50-pin flex cable (similar to the one on the Raspberry Pi Camera Module), and the driver board connects to your Pi using a HDMI lead. To save space in our build, we used a HDMI coupler adapter but any HDMI lead will work.

Mounting the driver board

As we are connecting the driver board to our Raspberry Pi using a HDMI couple adapter, we need to make sure it is as close to the Raspberry Pi as needed. We connected the HDMI to the Pi and the driver board, then used a pencil to mark 8 holes on the bottom panel of our RaspCade inline with the mounting holes on the driver board and the Pi. We then drilled 8 holes in the panel and used the standoffs to secure both the Pi and driver board in place.

Mounting the screen

Before you secure the screen in place, it is a good idea to check that it lines up nicely first. We drew around the screen on the back of the RaspCade panel with a pencil when we were happy, so we could line up the screen when taping it in place. We then applied insulation (or electrician’s) tape around the edges of the screen to ensure that it was held securely in place. Once the cabinet is assembled, nobody will see this so it doesn’t have to be perfect! This way, we could keep the design simple and cut out unnecessary parts.

Powering the screen

As the screen needs to be powered separately to the Pi, the Qubit included a barrel jack connector that also provided power to the Pi, via a micro-USB connector (see the close-up of the Qubit to see how this was done). As we used the barrel jack connector, our power supply also uses this (rather than micro-USB), but it is relatively simple to convert an existing Pi power supply to barrel jack instead of micro-USB if you wanted to. Just be sure to use a decent power supply - we recommend using at least 2.5A - to ensure you have enough power.

Connect everything together

Once you are happy that your screen is mounted in the right place and that your driver board and Pi are too, it is now time to connect everything together. Connect the 50-pin flex cable from your screen to the driver board (the same way you would for the Camera Module) and then connect your HDMI adapter / lead from your driver board to your Pi. You will then need to connect the power leads (one to the driver board and the other to the Pi) and then connect your power supply. We are almost ready to power up!

4. Cabinet assembly

Our RaspCade Designs

You are going to need a laser-cut RaspCade to get started, but we designed one so you don’t have to. Designed in Adobe Illustrator and saved as an Encapsulated PostScript (or EPS), our RaspCade cabinet is optimised for online laser-cut services so getting your own cabinet is as simple as downloading our design (https://www.raspberrycoulis.co.uk/download/472/) and then uploading it to your chosen laser-cut service. Jason Barnett (@boeeerb) at Cyntech kindly helped with our first protoype, and we used Just Add Sharks (http://justaddsharks.co.uk/) for our final cut, which cost us around £15 including delivery.

Some drilling necessary

To allow for some wiggle room when assembling the RaspCade, you may have to drill your own mounting holes to suit. As we used the Qubit case for the screen, we glued a layer from this to our base as it meant we could mount the LCD driver board and Pi very easily, but it is equally easy to add your own mounting holes and standoffs.In our build, we used a small drill bit to add several mounting points on the base unit, so that we could install standoffs for the PiCade PCB, as well as holes for the two speakers.

Mounting the speakers

It is very easy to mount the speakers as the ones we used come with 4 holes that are ideally suited to M4 bolts. After placing our speaker in the right position first, we marked the positions for our holes with a pencil, drilled the holes and then used the countersink bit to countersink the hole so that the bolt would sit flush with cabinet when assembled. It was then very simple to solder the positive and negative wires to each speaker, ready to connect to the PiCade PCB. A quick tip here is to put some coloured electrical tape around the positive wires so you can find them quickly later.

Assembling the cabinet

Our RaspCade design includes simple box joints so assembling the cabinet is pretty straight forward. We recommend doing a test run before gluing together, just so you are confident you get each panel the right way round! Using a strong wood glue, start by gluing one of the side panels to the base unit and then let that dry. We propped ours against a wall whilst the glue dried (which can take 24-hours) to ensure it was held in the right position. We then added the other side panel, repeating the same process.

Let the glue dry!

The hardest part for us was waiting for the glue to dry properly before starting the next panel! However, it is worth waiting to be sure that the glue has dried properly otherwise it could ruin your build. When we added the top panel, we tied some string around the sides and placed a small weight (tin of beans would do!) on top, to hold the panel together whilst the glue dried. This meant that we had a perfectly square cabinet frame once everything had dried, and now we can add some internal parts including our Raspberry Pi!

Connect your wires

Before gluing all panels together, we found it easier to put our electronics in place first. We connected our buttons, joystick and speaker wires to the PiCade PCB and then screwed the PiCade PCB onto the standoffs so it was secured inside. We then glued the front panel in place, then the joystick panel and then finished off with the screen, ensuring we waited for the glue to dry each time. Lastly, we added two small jewellery box hinges to the back panel and a magnetic catch so that we could get to the insides of our RaspCade quickly and easily if needed!

5. Software

RetroPie

This part is pretty straight forward, we will simply be installing RetroPie on the Pi and configuring our controls one the first boot. Thanks to the Picade PCB, all buttons are detected as keyboard inputs, so when RetroPie first boots, all we need to do is follow the on-screen prompts and press the relevant buttons (where applicable) and everything should be good to go!

NeoPixels

As you can see, we have included some NeoPixels within each arcade button to add a flashy lighting effect. There are extensive guides on how to get NeoPixels up and running over on Adafruit's site, so we won't cover that in detail here. However, we did use a Trinket 5V to power and run the NeoPixels, which is powered via USB connected to one of the Pi's spare ports.

ROMs

Due to copyright issues, this guide will not cover the scope of ROMs but a quick Google search will provide a lot of information on this!