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Project 9 — Retro Gaming with RetroPie

A Note on ROMs and Copyright

What You Will Need

Step 1 — Flash the RetroPie Image

RetroPie provides pre-built SD card images that boot directly into EmulationStation (the game launcher front-end). This is the fastest way to get started.

• Download the RetroPie image for your Pi from retropie.org.uk/download — choose the correct version for your Pi model (Pi 4/400, Pi 3/3B+, etc.)
• Flash the image to your microSD card using Raspberry Pi Imager — click Choose OS → Use custom and select the downloaded .img.gz file
• Insert the card, connect a controller and keyboard, connect to your TV, and power on
• The first boot expands the filesystem — this takes 1–2 minutes; a second automatic reboot follows

Step 2 — Configure Your Controller

On first boot, EmulationStation immediately asks you to map your controller. Hold down a button on the controller you want to configure — EmulationStation detects it and walks you through each button.

• Hold any button on your controller when prompted — it detects the device
• Follow the on-screen prompts: D-Pad, face buttons (A/B/X/Y), shoulder buttons, Start, Select
• For buttons your controller doesn't have, hold any button for a moment to skip them
• When done, press the button you mapped to A to confirm

Bluetooth controller pairing

For wireless controllers, pair them first via the RetroPie configuration menu:

• From EmulationStation, press Start → RetroPie Configuration
• Select Bluetooth
• Choose Register and Connect to Bluetooth Device
• Put your controller in pairing mode (hold the pairing button — varies by controller), then select it from the list
• For PS4/PS5 DualShock: hold the PlayStation button + Share button together until the light bar pulses
• For Xbox Wireless: hold the pairing button on the back of the controller until it flashes rapidly

Step 3 — Transfer ROMs

ROMs are stored on the Pi in /home/pi/RetroPie/roms/, with each system in its own subfolder. There are three ways to transfer them:

Method 1 — USB drive (simplest)

• Format a USB drive as FAT32 or exFAT
• Create a folder called retropie on the drive
• Plug the drive into the running Pi — RetroPie detects it and creates the correct folder structure on the drive automatically (takes about 30 seconds)
• Unplug, copy your ROMs into the appropriate system subfolders on the drive
• Plug the drive back into the Pi — RetroPie copies the ROMs to the SD card automatically

Method 2 — Network file share (SAMBA)

# RetroPie's SAMBA share is enabled by default
# On Windows: open File Explorer and type in the address bar:
\\retropie
# On Mac: Finder → Go → Connect to Server → smb://retropie
# Drag ROMs into the appropriate system folder

Method 3 — SCP / SFTP

# From your PC terminal (replace with your Pi's IP):
scp SuperMarioWorld.smc pi@192.168.1.42:~/RetroPie/roms/snes/

After transferring ROMs, restart EmulationStation to see them (Start → Quit → Restart EmulationStation).

Step 4 — Scrape Artwork with Skyscraper

A bare list of ROM filenames is functional but uninspiring. Scrapers fetch box art, screenshots, descriptions, ratings, and video previews from online databases, transforming your game list into a beautiful visual library.

With scraped artwork, each game shows its box art, rating, description, and release year. Video previews play as you browse. It makes the whole experience feel genuinely polished.

RetroPie includes Skyscraper as its recommended scraper. Run it from the RetroPie Setup menu:

• Press Start → RetroPie Configuration → RetroPie-Setup
• Navigate to Configuration / Tools → skyscraper
• Select Gather resources → choose your source (ScreenScraper is recommended — create a free account at screenscraper.fr for higher rate limits)
• Select which systems to scrape
• After gathering, select Generate game list & artwork
• Restart EmulationStation to see the results

Command-line scraping (faster for large collections)

# Scrape all SNES ROMs from ScreenScraper, then generate artwork
pi@raspberrypi:~$ Skyscraper -p snes -s screenscraper -u "username:password"
pi@raspberrypi:~$ Skyscraper -p snes
# The second command (without -s) generates the gamelist from cached resources

Step 5 — Emulator Performance by System

Different systems require different levels of Pi hardware. Here's what to expect:

Step 6 — Save States and Rewind

Save states let you save and load your exact game position at any moment — no more hunting for in-game save points. Rewind lets you roll back a few seconds of gameplay, effectively giving you infinite retries on tricky sections.

Save state controls (default)

Enable rewind

Rewind is disabled by default because it uses extra memory and CPU. Enable it per-system if needed:

• During a game, press Select + X to open the RetroArch menu
• Go to Settings → Frame Throttle → Rewind → set to ON
• Quick Menu → Overrides → Save Core Override to save for all games on this system

Step 7 — CRT Shaders

Modern flat displays show retro games as sharp pixel art — technically accurate but not how they looked on the CRT televisions they were designed for. RetroArch shaders simulate the soft scanlines, phosphor glow, and colour blending of CRT screens with impressive accuracy.

• During a game, press Select + X to open the RetroArch menu
• Go to Shaders → Load Shader Preset
• Navigate to shaders_glsl/crt/ (or shaders_slang/crt/ on Pi 4)
• Try crt-pi.glslp first — it's designed specifically for the Pi and runs at full speed
• For a more authentic look: crt-aperture.glslp simulates an aperture grille monitor (like a Sony Trinitron)
• Press Apply Changes, then save as a core or game override to make it permanent

Step 8 — RetroAchievements

RetroAchievements is a free service that adds modern achievement systems to classic games — just like Xbox Achievements or PlayStation Trophies, but for your retro collection. Over 400,000 achievements exist across thousands of games.

• Create a free account at retroachievements.org
• In EmulationStation, go to RetroPie Configuration → RetroArch
• Navigate to Settings → Achievements
• Enable Achievements, enter your Username and Password
• Enable Hardcore Mode (optional) — disables save states and rewind for a purist experience with double the achievement points
• Save and exit — achievements now unlock in-game with a pop-up notification

Step 9 — Home Assistant Integration

If you set up Home Assistant in Course 1 Project 5, you can create an automation that reacts when gaming starts or stops — dimming the lights, switching on the TV, or sending a notification. RetroPie can call a webhook when a game launches or exits.

Create a RetroPie runcommand script

RetroPie runs scripts at specific points in the game lifecycle. Create a script that fires when a game starts:

pi@raspberrypi:~$ nano /opt/retropie/configs/all/runcommand-onstart.sh

#!/bin/bash
# Called when a game starts
# $1 = system name (e.g. "snes"), $2 = emulator, $3 = ROM path, $4 = command
SYSTEM="$1"
ROM="$(basename "$3" | sed 's/\.[^.]*$//')"   # ROM filename without extension

# Fire a webhook to Home Assistant
curl -s -X POST \
  "http://homeassistant.local:8123/api/webhook/retropie_start" \
  -H "Content-Type: application/json" \
  -d "{\"system\": \"$SYSTEM\", \"game\": \"$ROM\"}"

pi@raspberrypi:~$ chmod +x /opt/retropie/configs/all/runcommand-onstart.sh

Create a matching script for when a game ends:

pi@raspberrypi:~$ nano /opt/retropie/configs/all/runcommand-onend.sh

#!/bin/bash
curl -s -X POST \
  "http://homeassistant.local:8123/api/webhook/retropie_end" \
  -H "Content-Type: application/json" \
  -d "{\"event\": \"game_ended\"}"

pi@raspberrypi:~$ chmod +x /opt/retropie/configs/all/runcommand-onend.sh

Home Assistant automation

In Home Assistant, create two automations triggered by the webhooks:

automation:
  alias: "RetroPie — Game Started"
  trigger:
    platform: webhook
    webhook_id: "retropie_start"
  action:
    # Switch on the TV via HDMI-CEC or smart plug
    - service: media_player.turn_on
      target:
        entity_id: media_player.living_room_tv
    # Dim the lights to 30% for gaming ambience
    - service: light.turn_on
      target:
        entity_id: light.living_room
      data:
        brightness_pct: 30
        color_temp: 370   # warm white
    # Optional: send a notification
    - service: notify.mobile_app
      data:
        message: "🎮 Gaming started: {{ trigger.json.game }}"

automation:
  alias: "RetroPie — Game Ended"
  trigger:
    platform: webhook
    webhook_id: "retropie_end"
  action:
    - service: light.turn_on
      target:
        entity_id: light.living_room
      data:
        brightness_pct: 100

Step 10 — Useful RetroPie Tweaks

Enable SSH

# SSH is disabled by default on RetroPie images
# Enable it via the RetroPie Configuration menu:
# RetroPie Configuration → RetroPie-Setup → Configuration / Tools → sshd → Enable
# Or enable at first boot by placing an empty file called 'ssh' in /boot/

Overclock the Pi 4 (optional)

pi@raspberrypi:~$ sudo nano /boot/config.txt

# Pi 4 overclock — improves N64 and Dreamcast emulation
# Requires a good heatsink or case with active cooling
over_voltage=6
arm_freq=2000
gpu_freq=750

Run RetroPie on top of Raspberry Pi OS

pi@raspberrypi:~$ sudo apt update
pi@raspberrypi:~$ git clone --depth=1 https://github.com/RetroPie/RetroPie-Setup.git
pi@raspberrypi:~$ cd RetroPie-Setup
pi@raspberrypi:~/RetroPie-Setup$ sudo bash retropie_setup.sh
# Choose: Basic install → installs EmulationStation and all core emulators

Set up automatic backups of save files

# Save files are in /home/pi/RetroPie/saves/
# Add a cron job to back them up nightly to an external drive or network share
pi@raspberrypi:~$ crontab -e

# Backup saves every night at 2am
0 2 * * * rsync -av /home/pi/RetroPie/saves/ /media/usbdrive/retropie-backup/saves/

Troubleshooting

Quick Reference