Raspberry Pi Retro Game Console

This project takes the original concept of the PiGRRL and makes it more powerful, using a Raspberry Pi 2. It's about the same size but features more buttons (D-Pad, A,B,X,Y, L, R, pause and start.) and four extra buttons on the PiTFT. It's sporting a small audio amplifier and speaker, so you can enjoy the crispy sounds of 8-bit goodness. 

Easier to build!

With this update, we really wanted to make it easier to build. We've dramatically cut the build time in half by making a custom gamepad PCB. Just solder in the buttons and an IDC box header to the gamepad PCB - No more tedious button wiring!

Project Expectations

This project is geared towards beginners, but is still a big project to take on. This guide will walk you through all the necessary steps to wire, assemble and build your very first Raspberry Pi game console. It does require a good amount of soldering, wire tinning and good ol' elbow grease, but don't be discouraged! If your dedicated to take on this project, it'll only take a weekend to make.

Adafruit Parts

• Raspberry Pi 2 or Raspbery PI 3
• 2.8" PiTFT Plus
• PiGRRL Gamepad PCB
• PowerBoost 1000c
• 2500mAh battery
• PAM8302 2.5W Audio Amp
• Mini Metal Speaker
• 40pin GPIO ribbon cable
• Slide Switch
• 10x 6mm + 2x 12mm tactile buttons
• 1x 2by20 pin IDC box header

Tools and Supplies

• 3D Printer + Filament
• Soldering Iron + Solder
• 30AWG + 26AWG Wire
• Helping Third Hands / Panavise
• Heat Shrink
• Glue / Mounting Tack
• Wire Stripper / Cutters
• Filing Tool / Hobby Knife
• 14x #4-40 3/8 machine screws
• 6x #2-56 3/8 machine screws
• #4-40 Screw Tap
• #2-56 Screw Tap

Wired Connections

The diagram above depicts the connections for the power, audio and gamepad. Use this as a reference for wiring the components. Note, the length of wires and position of components are not exactly how the circuit will be - it’s just a diagram to show connections.

The 2.8" PiTFT connects to the Raspberry Pi's GPIO header. A GPIO ribbon cable plugs into the GPIO breakout of the PiTFT and connects to the PiGRRL gamepad PCB. 

Material Options

The top case, bottom case and shoulder mount should be printed in hard plastic like PLA, ABS or other. We recommend using PLA to minimize warping. ABS and other filaments requires a heated bed.

Parts

Download the parts and print them out accordingly - referencing the table below for material suggestions. If you don't have access to a 3D printer, use a service like 3DHubs.com to send them to you.

Dimensions

• Top Part – 141mm x 91mm x 18mm (5.55in x 3.85in x 0.71in)
• Bottom Part – 141mm x 91mm 16mm (5.55in x 3.85in x 0.63in)

Test Fit Openings

Use a hobby knife to remove any excess bits from printing. Lay the components over the standoffs to see if mounting holes line up. See if the port cutouts are in the right place. If they don't, use a filing tool to open them up.

Finishing Parts

You can smooth the parts by applying epoxy resin like Smooth-On's XTC-3D. To finish the surface, wait for it to dry and sand it down. Apply a filler primer paint and a colored top coat of spray paint to make it extra smooth.

Download & Burn RetroPie

Game emulation is handled by a package called RetroPie. It’s a complete Linux distribution designed specifically for running classic games on Raspberry Pi.

Download the current version from the RetroPie web site, then write this to an SD card using Etcher or similar software.

We’ll then make some modifications to tune this for the PiGRRL’s buttons and small display.

Setup will require an HDMI monitor, USB keyboard and a network connection (either WiFi or Ethernet). This is best done before the Pi is enclosed in the PiGRRL case. If you have a spare Raspberry Pi board around, that’s an ideal option…you could prepare the software on that system and then move the card over to the PiGRRL 2.

Setup RetroPie

Insert the RetroPie card to your Pi, attach monitor and keyboard (and Ethernet, if networking that way), then power the system from a USB power source (a USB phone charger or a powered USB hub can usually work). The system will automatically reboot once (it needs this to make use of the whole SD card), then on second boot it will ask to configure the game controls…

The PiGRRL buttons don’t work yet; this is normal. For initial setup, use the USB keyboard to select the D-pad directions (arrow keys), Start, Select, A and B keys. For anything else, just hold down the space bar or other key to skip that item . Don't worry, we'll re-do the keymap later once we've finished assembly! When finished, you’ll see a graphical interface called Emulation Station where you’ll select games and other options.

Let’s get this Raspberry Pi on the network first. If using Ethernet, it’s a simple matter of plugging in. If WiFi, from the main EmulationStation screen, access the RetroPie settings using whatever key you’ve assigned as the “A” button. You’ll see WIFI in this list:

With networking enabled, we can now access the remaining software needed for the PiGRRL 2 experience. There are a couple ways to do this…

• BEST: Use an ssh terminal client to log into the Raspberry Pi at retropie.local
  This is recommended, as you can just copy-and-paste the commands that follow. The default name and password are “pi” and “raspberry,” respectively.
• OR: Press “F4” to exit EmulationStation for a command-line prompt (works, but you’ll need to type these commands exactly).

Install PiTFT (fbcp) Support

This first sequence configures the system for the PiTFT display:

Select the “PiGRRL 2” option, which sets up various system parameters to match this project.

Answer “NO” to the reboot question…

Installing Keypress (retrogame) support

let’s take care of this second script, which enables the PiGRRL buttons:

Again, select the “PiGRRL 2” option. When finished, now you can reboot when prompted.

After rebooting, the HDMI monitor may display a “no signal” message. This is normal. Not all monitors can handle the resolution setting we’re using. Once the PiTFT is wired up, that will be the primary display.

Also, after the system is assembled with the PiTFT and controls, you’ll need to re-do the controller setup. This might wait ’til all the parts are assembled in the case.

Uploading ROMs

Check out the Wiki on the RetroPie Setup page for how to upload ROMs:

Exiting ROMs

Retropie has changed how to exit out of ROMs/Emulators. Hold down the Pause & Start buttons at the same time to exit.

Remapping Controls

The buttons are premapped to work with NES and SNES emulators. If you'd like to remap the controls, you'll need to modify the retrogame.cfg file in /boot.

Make sure the Raspberry Pi is configured for Wifi. Open up terminal and ssh into the Pi. (Default username: pi password:raspberry)

Then follow the retrogame tutorial to set it up the way you like!

Testing Controls

If you log in (via SSH or F4 shell) you can see exactly what keypresses are detected by running evtest then select 1 (or whatever retrogame is numbered):

Make sure each keypress works and matches the table below!

Default Controls

Below is a table of the controls set to the GPIO. Use this as a reference if you ever need to revert when changing something.

PiGRRL Gamepad Design

The gamepad was designed in EagleCAD and available to download and modify. It's also a shared project on Oshpark.

PiGRRL Gamepad PCB

Let's start assembly by putting the gamepad together. Gather up 10x 6mm tactile buttons and a 40pin IC box header. 

Prep 6mm Tactile Buttons

To make it easier to insert the buttons to the PCB, use a pair of flat plier to straighten out the four leads of each button.

Soldered Gamepad PCB

Here's what the soldered gamepad will look like. Clean and Shiny! 

Tap Gamepad PCB Mounting Holes

Now is a good time to tap the mounting holes of the gamepad PCB. We need to create threads on each hole so that it's easier to mount to the case. You can use a #4-40 sized tap tool, or a #4-40 machine screw to do this, just make sure to fasten as straight as you can.

GPIO #18 - LED Backlighting

Flip the 2.8" PiTFT display over and locate the pad with label #18. We need to cut this trace in order to properly use GPIO 18 (The Y Button is wired to this GPIO). By default, when GPIO 18 is triggered to ground, it will disable the LED backlighting on the display - Cutting the trace here will disable that feature.

Cut Trace #18

Use a hobby knife to mark in between the two pads and make sure it is deep enough to fullly break the trace.

That's pretty much all we need to do to the PiTFT display!

PiCable Resizing

In this section, we'll resize the PiCable so it's more manageable once installed inside the case. Its some what optional - you can skip it but if you find space too tight when closing the case, you may want to resize the PiCable.

The stock ribbon cable is 152.4mm(6") in length, but I've found shortening it down to 108mm is just the right fit for the length we need.

Cut Cable

With the cable split in two, set aside the longer end and keep the short end handy - we need to remove the connector from the end of it.

Mash Top Piece to Connector

Unless you're incredibly strong, you won't be able to press the top piece back onto the connector because it's hard to puncture the wire with the pointy teeth. The easiest way to do this is to use a rubber mallet to smash the pieces together. I recommend doing this on a hard surface (like on the floor) while holding the connector in place. Tap the top piece in sessions as straight as you can and be careful not to mash your fingers in the process.  If all goes well, the teeth from the connector will puncture the ribbon cable and close the two pieces back together. 

Shortened Pi Ribbon Cable

And there you have it! A shortened Raspberry Pi Ribbon Cable. Bit of a hack, I know - But it really does make closing the case much easier in when we're all done.

Measure Wires for Amp and Speaker

We'll need two pieces of 30AWG wires to connect the speaker to the amp. We recommend using silicone-coated stranded wire. Measure about 9cm in length for each wire. You don't have to use different colored wires, but we recommend it to help tell them apart.

Prep PowerBoost 1000C

Secure the PowerBoost to the pair of helping third hands. Apply solder to the following pins: Positive(+) out, Negative(–) out, EN, GND, G and 5V.

Connected Amp, Speaker and PowerBoost 1000C

Now our amplifier and speaker are wired up the PowerBoost 1000C.

Wired Power Circuit

Now we have our amp, speaker, PowerBoost and slide switch all wired up and connected. Now's a good time to take a break or continue!

Prep Wires for Rasp Pi Audio

To connect the amp to the Raspberry Pi 2, we'll need two wires. Cut two pieces of 30AWG wires to about 10cm in length. Strip and tin the tips of each wire.

Prep Raspberry Pi Audio Pins

On the bottom of the Raspberry Pi 2 PCB, locate the audio jack and inspect the three pin connected to the component.

Take note of the two circles highlighting the pins. The left pin (blue) will connect to the negative pin on the amp, while the right pin (red) connects to the positive pin. The middle pin does not need to be tinned (disregard the tinning in the photo).

Place the tip of the soldering iron over the pin and apply a small amount of solder. This will make connecting wires to the audio amp much easier.

Connect Wires to Raspberry Pi

Solder the new wires to the pins on the bottom of the Raspberry Pi. The negative(blue) wire connects to the left pin, while the positive(ed) wire connects to the right pin.

Connect Wires to Amp

Solder the negative (blue) wire to the A– pin on the amp, and the positive (red) wire to the A+ pin on the amp.

Prep 12mm Tactile Buttons

Next up we need to prepare two 12mm buttons for our shoulder L and R buttons.

Start by clipping two of the four legs from each button. Use a pair of flat pliers to flatten out the legs so they point out like in the photo. Secure the button to a pair of helping third hands and apply solder to each leg to tin them.

Prep Wires for Shoulder Buttons

We'll need two sets of wires (four total) to measure about 14cm in length. Strip and tin the tips from each wire and thread them through one big piece of heat shrink tubing. This will keep the wires together in a neat bundle.

Connect Wires to Buttons

Solder wires to the legs of each button - Like before, use a pair of helping third hands to assist you. Polarity doesn't matter too much on these buttons, but you can reference the photo.

Shoulder Buttons

OK, now we have our shoulder buttons prepped and ready to wire into our gamepad PCB. The next page will go through the final connections for our build.

Prep Wires for Gamepad PCB

Now we need to connect our gamepad PCB to the PowerBoost 1000C. We'll need two 26AWG (which is thicker than the 30AWG we've been using so far) that's about 14cm in length. Like before, strip and tin the ends of each wire. Then, let's slip on a long piece of heat shrink tubing to keep the two wires together.

Connect Gamepad PCB to PowerBoost 1000C

Now we can solder in the two wires connected to the power pins of the gamepad PCB to the power output pin on the PowerBoost. The 5V wire from the gamepad connects to the positive pin on the PowerBoost, and the Ground wire from the gamepad connects to the negative pin on the PowerBoost.

Final Wired Components

OK, now all of our wires are connected, yay! Our components are connected and we're ready to mount them to the case. In the next page, we'll finish up our build!

Test Components

Its good practice to test all of our components before we start mounting things to the enclosure. Just as a sanity check, this ensures our components and wiring is all good and working. Go ahead and insert your microSD card into the Raspberry Pi - make sure the software is already installed and loaded.

Once thats sorted, plug in the JST connector from our battery into the PowerBoost 1000C. Next, plug the Pi ribbon cable into the PiTFT GPIO breakout and connect the other end to the PiGRRL Gamepad. Then, lay the PiTFT over the Raspberry Pi and press it down to connect together the GPIOs until they’re fully seated.

Now you can flip the slide switch to power on the circuit. The PiTFT should display the boot up scripts and automatically launch RetroPi Emulationstation. Test out the DPad and buttons to see if everything works as expected. You should hear audio once a ROM is loaded. If you don’t have any loaded, reference the software page for uploading ROMs (You should be able to launch Quake from the Ports section).

If the audio isn’t working, or the buttons aren’t triggering, you’ll want to double check your wiring. If you are not sure how to use a multi-meter to check for any shorts and continuity, you may want to post up any specific issues in the Adafruit Forums, where our dedicated engineering support team can help you trouble shoot.

If everything works during your test, you should be safe to power down the Raspberry Pi and move onto the next page.

Connected PiTFT and Gamepad

Now our PiTFT display and Gamepad PCB are mounted to the case. Press the buttons on the PiTFT and Gamepad to test them and see they feel good. If the buttons get stuck, the gamepad isn't flush with the standoffs. 

Install Speaker

Let's go ahead and pop the speaker into the case. Lay the speaker over the cavity with the grill and press it down to snap it into place. The wire should be oriented in a position so it's not in the way of the corner standoff.

Install Switch

Now if a good time to insert the slide switch into the bottom case. Take note of the OFF position of the slide and install it to your liking (I prefer down is OFF, up is ON).

Test PowerBoost Circuit

Grab the lipo battery and plug in the JST connector to the JST port on the PowerBoost 1000C. Flip the slide switch on, and see if the circuit works! The blue LED indicates the battery is charged and the circuit is powered on.

If the LED doesn't light up, you either have a defective PowerBoost, or a short. You'll have to double check your wiring for short using a a multi-meter. If you have any issues or questions, please post it on support forums at http://forums.adafruit.com/

Almost Done!

In the next page, we'll close up the case and finish the build!

Insert microSD Card

Lastly, insert the microSD card if you haven't already. You should have already burnt the PiGRRL image to the SD card. If not, go ahead and do that now!

Completed Build!

Hazzah! The PiGRRL 2 game console is finally finished and ready to play! Turn it on and RetroPie / Emulationstation should automatically boot. The buttons are premapped to the expected controls. Reference the Software page for uploading ROMs and remapping controls.

Share Your Creation With Us!

If you built PiGRRL 2, we'd love to see it and share it with the community! Post a make on the thingiverse project page, share it on Instagram or twitter with hashtag #PiGRRL2. 

Audio Issues

Are you hearing a strange sound when powering up the Pi? The battery might be in a bad spot where it's causing interference noise with the audio jack. If you remove the mounting screws from the Pi on the back of the bottom case, you can separate the two parts while it's still powered. 

Once they're separated, reposition the battery and listen carefully to the noise. Position the battery in a spot where the noise is less prominent and mount it in place with tape or mounting tack.

Another option you can try is to adjust the pot on the sound amp. Lowering the gain may fix the sound interference when repositioning the battery doesn't work.

The best location for the battery I've found is directly tucked inbetween the Raspberry Pi and the PiTFT display. 

No Audio

Retropie has sound options built into the software. It may be muted or set to really low. To adjust it, press the "Start" button to bring up the Menu. Then, use the D-Pad to highlight “Sound Settings”. Use the “A” button to select and D-Pad to increase volume. Press the “B” button to exit.

Pressing Button Turns Off Screen

If the PiTFT display turns black when you press one of the gamepad buttons, the trace that controls the backlighting might need to be cut deeper. The label #18 on the back of the PiTFT is active by default - triggering it turns the display off. Make sure this trace is cut to deactivate this feature.

PiTFT Shows Only White Screen

 If the PiTFT display only display a white screen, chances are the img wasn't properly burnt to the SDcard. Be sure to follow the steps Easy SD Card Setup guide to correctly burn the image. 

Custom Mute Function

If you're interested in making one of the PiTFT buttons mute the audio, Martin O'Hanlon made a function.

Better Sound quality

A suggestion from the forums!

1)Wrap the battery in copper tape and then electrical tape. Then you solder a wire from the ground of the audio circuit to the copper. It helps to solder to a random piece and then stick it to the battery so you're not soldering on the battery itself as it's dangerous.

2)Buy tiny ferrite beads and put them around the speaker wires. Ferrite beads provide EMI shielding and putting them around the speaker wires worked like a charm.

Issues, Problems, Need Help?

If you encounter any technical problems with the Raspberry Pi software, components or otherwise, please post up your issue, including photos of your wiring on the Adafruit Forums. Our support team will be able to assist you there.

Safely Shutdown via Tactile Switch

Its a good idea to safely turn off your Pi with a good sudo shutdown -h now but that often means pulling out a keyboard or connecting to the console. With our kernel we added a cool module that will let you turn any GPIO into a power button. Since there's a couple of tactile switches right there on the front, lets turn one into a power button. Press once to properly turn off the pi, press again to start it up. Isn't that nice?