How to make a retro arcade game with a Raspberry Pi

Why ?

• Because it's just too cool !

Instructions

1. Make sure  that you have all the other parts needed for your Raspberry Pi: power supply, USB microB cable (for power), HDMI or composite monitor, USB keyboard, mouse and a network connection (a wired Ethernet connection is easier, but WiFi with a supported USB adapter is possible with a few additional steps).
2. Download the rasbian wheezy distro from http://www.raspberrypi.org/downloads

a)     I used the 2013-09-25-wheezy-raspbian.zip from  http://downloads.raspberrypi.org/raspbian_latest

b)     Unzip the file and note the location of the img file (2013-09-25-wheezy-raspbian.img).

3. Insert the SD card in the card reader, connect to your computer and figure out which drive it is mapped to (e.g. E:, F: etc.)
4. Download the fedora installer from : http://fedoraproject.org/wiki/Fedora_ARM_Installer#Windows_Vista_.26_7
5. Run the fedora-arm-installer-2.exe, and point the source to the the raspbian wheezy image (from step 2b above) , and the destination to the SD card drive (from step 3 above)

6. Prepare your Raspberry PI to bootup : Insert the SD card, connect the USB keyboard, HDMI monitor, and Ethernet cable / usb wireless adapter and then power on the raspberry pi
7. If all is ok, the pi should start booting up and take you to the final configuration prompt
8. When the system is started for the first time, the raspi-config utility runs automatically.

·       You should select the following options:

·       Expand root partition (this lets us use the full capacity the SD card).

·       These steps are optional but recommended:

·       If using an HDMI monitor, disable overscan.

·       Change hostname. I called my system “gaming-pi” to distinguish it from other Raspberry Pis

·       already on the network.

·       Change password for "pi" user (I ignored this, as I will change this later)

·       Change memory split. Allocate at least 64 MB to the GPU (I allocated 128 MB as I want faster graphics)

·       Enable SSH server (for administration access to the Raspberry Pi over the network).

·       Make sure that keyboard layout is selected to US (I had trouble with the @ key, and had to come back and change it)

·       These options should NOT be selected:

·       Start desktop on boot (we’ll run X11 manually when we need it).

·       You can always change any of these options by running “sudo raspi-config” at a later time

·        

9. Check your audio (I wanted audio out through hdmi, and it is not enabled / set by default

·       To test if the hdmi audio is even working or not,

o   cd /opt/vc/src/hello_pi/

o   ./rebuild.sh

o   /opt/vc/src/hello_pi/hello_audio/ /hello_audio.bin 1

·       Finally, to make this persistent, and pass through to the mame emulator

o   sudo amixer cset numid=3 2

10. Download and install an emulator.

·       I used http://mame4all-pi.googlecode.com/git/mame4all_pi.zip

·       Install winscp and transfer the zip file to /home/pi and unzip it

·       /home/pi/mame4all_pi/mame is the executable (you will most likely have to do a chmod +x on it)

·       You can transfer zips of your roms to the /home/pi/mame4all_pi/mame/roms folder and run “/home/pi/mame4all_pi/mame” to test it out.

·       The controls and keyboard mappings etc. are in the /home/pi/mame4all_pi/mame/readme.txt file

11. You can edit the file .bashrc in your home directory  (/home/pi) to set up simpler aliases for this, or add the directories to your PATH (remember to source ./bashrc or reboot for it to take effect)
12. Download retrogame

·       Download zip from https://github.com/adafruit/Adafruit-Retrogame  and scp it to the pi in /home/pi/Adafruit-Retrogame-master

·       Make the wired connections from the controls to the raspberry pi. I used a common ground for almost all connectors 

·       On the pi, map the GPIO pin to the action you need. Refer to http://www.ultimarc.com/ipac2.html and http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/include/linux/input.h?v=2.6.11.8 to figure out the mame mappings.

o   cd /home/pi/Adafruit-Retrogame-master

o   Edit the retrogame.c to define your mappings. I have the following mappings (not that the #’s are the GPIO pin #’s from the raspberry pi)

   {  2,      KEY_LEFT     }, // P1 Left

        {  3,      KEY_RIGHT    }, // P1 Right

        {  4,      KEY_UP       }, // P1 Up

        { 17,      KEY_DOWN     }, // P1 Down

        { 27,      KEY_LEFTCTRL }, // P1 Action 1 (Fire etc.)

        { 22,      KEY_LEFTALT  }, // P1 Action 2

        { 10,      KEY_1  },       // Start 1 Player

        {  9,      KEY_2  },       // Start 2 Player

        { 11,      KEY_5  },   // Insert Coin 1 (jumped to coin 2 - KEY_6)

        { 18,      KEY_D  },       // P2 Left

        { 23,      KEY_G  },       // P2 Right

        { 24,      KEY_R  },       // P2 Up

        { 25,      KEY_F  },       // P2 Down

        {  8,      KEY_A  },       // P2 Action 1

        {  7,      KEY_S  }        // P2 Action 2

o   make

·       To test this out

o   sudo modprobe uinput

o   sudo ./retrogame

·       To make this persistent across reboots

o   sudo sh -c 'echo uinput >> /etc/modules'

o   sudo nano /etc/rc.local

o   Before the final “exit 0” line, insert this line:

§  /home/pi/Adafruit-Retrogame-master/retrogame &

·       Setup additional user – mainly for winscp / transfer in background

o   Check groups for user pi

§  pi@gamingpi ~ $ sudo groups

§  pi@gamingpi ~ $ sudo su -

§  root@gamingpi:~# groups pi

§  pi : pi adm dialout cdrom sudo audio video plugdev games users netdev input indiecity spi gpio

o   Add the new user “pi2”

§  root@gamingpi:~# useradd pi2

o   Add pi2 to all the groups that pi belongs to

§  root@gamingpi:~# adduser pi2 pi

§  root@gamingpi:~# adduser pi2 adm

§  Repeat for all groups…

o   Change password for user pi2

§  sudo passwd pi2

o   Create home directory for user pi2

§  mkdir /home/pi2

§  chown /home/pi2 pi2

13.  Setup auto login

·       Step 1: Open a terminal session and edit inittab file.
sudo nano /etc/inittab

·       Step 2: Disable the getty program.
Navigate to the following line in inittab
1:2345:respawn:/sbin/getty 115200 tty1
And add a # at the beginning of the line to comment it out
#1:2345:respawn:/sbin/getty 115200 tty1

·       Step 3: Add login program to inittab.
Add the following line just below the commented line1:2345:respawn:/bin/login -f pi tty1 </dev/tty1 >/dev/tty1 2>&1
This will run the login program with pi user and without any authentication

14.  Do overclocking for better graphics performance

·       Overclocking is supported by the Raspberry Foundation.

·       My overclocking settings which work well, (/boot/config.txt)

{{{

arm_freq=900

core_freq=300

sdram_freq=500

}}}

15.  Start the mame to autolaunch at login

·       Step 1: Open a terminal session and edit the file /etc/profile

sudo nano /etc/profile

·       Step 2: Add the following line to the end of the file

#only run the gaming emulator if user pi logs on locally on console

if [ `whoami` == "pi" ] && [ `tty` == '/dev/tty1' ] ; then

   /home/pi/mame4all_pi/mame

fi

End Result

Precautions

• Always use a multimeter to check the voltages and inputs vs outputs
• I fried 2 raspberry PI's to get the coin slot working... I kept wiring the leds (which were outputs) to the raspberry pi inputs, and the over voltage kept frying the pi's beofre i got wiser and got to the basics....