Basic setup :

Download latest Retropie install for Pi zero and burn it on SD card (a 8 gb sd card is enough)

Wifi setup :

Connect Pi Zero, add an USB dongle and configure wifi on /etc/network/interfaces :

auto lo
iface lo inet loopback
iface eth0 inet dhcp

allow-hotplug wlan0
auto wlan0

iface wlan0 inet dhcp
   wpa-ssid "Your Network SSID"
   wpa-psk "Your Password"

More information here : http://raspberrypihq.com/how-to-add-wifi-to-the-raspberry-pi/

Pi TFT screen setup :

You can then halt the pi and connect the Pi TFT screen.

Get the Adafruit kernel and software :

curl -SLs https://apt.adafruit.com/add-pin | sudo bash
sudo apt-get install raspberrypi-bootloader
sudo apt-get install adafruit-pitft-helper

sudo adafruit-pitft-helper -t 28r

Reboot and you can then test screen by sending random data to it :

cat /dev/urandom > /dev/fb1

dtoverlay=pitft22,rotate=270,speed=80000000,fps=40

More information here :

• https://learn.adafruit.com/adafruit-2-4-pitft-hat-with-resistive-touchscreen-mini-kit/easy-install#diy-installer-script
• https://learn.adafruit.com/pocket-pigrrl/software#pitft-setup
  

HDMI display cloning :

To show same display as HDMI output, you’ll need to clone video output.

rpi-fbcp is nice for that. Just clone the project, compile it and install it in /opt.

cd /home/pi/
git clone https://github.com/tasanakorn/rpi-fbcp
cd rpi-fbcp
mkdir build
cd build
cmake ..
make 
sudo chown root:root fbcp
sudo chmod u+s fbcp
cp fbcp /opt/

I put it in /etc/rc.local, just before exit 0

/opt/fbcp &

Audio :

Connect resistors and capacitor for audio like described here : https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio

I used GPIO 18 (pin 12) and 19 (pin 35).

(optionnal) you can clone WiringPi project, build it :

cd /home/pi/
git clone git://git.drogon.net/wiringPi
cd wiringPi
git checkout 78b5c32
./build

(optionnal) check all GPIO :

sudo gpio readall

curl -SLs https://goo.gl/V4JGF6 > gpio_alt.c
gcc -o gpio_alt gpio_alt.c
sudo chown root:root gpio_alt
sudo chmod u+s gpio_alt
sudo mv gpio_alt /opt/

and change then pin to output mode :

gpio_alt -p 18 -f 5
gpio_alt -p 19 -f 5

(optionnal) Check gpio :

sudo gpio readall

Pin 18 and 19 should show ALT0 and ALT5.

If that’s ok,try to play a file :

aplay /usr/share/sounds/alsa/Front_Center.wav

To reconfigure pin at boot, I’ve put thoses lines in /etc/rc.local, before exit 0 :

/opt/gpio_alt -p 13 -f 5
/opt/gpio_alt -p 18 -f 5

Map button on keyboard :

Then load my forked Adafruit-retrogame (2buttons branch) in order to use controller and compile it.

That version includes some changes to be compatible with GPIO used by audio and also to fix an issue with Neo Geo emulator (the "insert coin" should map tab key).

cd /home/pi/
git clone https://github.com/paulgreg/Adafruit-Retrogame.git
cd Adafruit-Retrogame
git checkout 2buttons
make retrogame
sudo chown root:root retrogame
sudo chmod u+s retrogame
cp retrogame /opt

Compile it and launch it from /etc/rc.local, before exit 0 :

/opt/retrogame &

Enable controls in emulator :

As explained on adafruit, add a new udev rule :

sudo vim /etc/udev/rules.d/10-retrogame.rules

And add that content :

SUBSYSTEM=="input", ATTRS{name}=="retrogame", ENV{ID_INPUT_KEYBOARD}="1"

Disable wifi :

If everything is working, comment wlan configuration in /etc/network/interfaces.

Print 3d parts :

Download files from that project and print them.

My files have been updated from Adafruit’s ones :

• https://learn.adafruit.com/pocket-pigrrl/3d-printing
• www.thingiverse.com/thing:807591/
  

Assemble :

Assemble and wire power boost (pin 2 and 6), solder buttons like explained on Adafruit’s page except UP button that you need to solder to pin 3 (GPIO 2).

Pin 12 (GPIO 18) is already used by audio.