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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →A Raspberry Pi Compute Module 4 (CM4) can power a handheld gaming console, but it cannot do so on its own: it needs a carrier board to expose connections for power, display, USB and controls. The most reliable approach is to bring up the CM4 and test the display, controls, audio and power on a development carrier before committing to a compact custom board and enclosure.
What you need to build a CM4 handheld
The CM4 is a Raspberry Pi 4-based system-on-module. Its processor, memory and optional eMMC storage sit on the module; two 100-pin high-density connectors carry signals to a separate carrier board. A handheld therefore needs more than a CM4 and a screen: it needs six integrated subsystems.
- Compute and carrier: the CM4 plus a development or custom carrier board to connect power, display, USB and GPIO.
- Display: an HDMI or MIPI DSI panel, its correct cable or adapter, and any required software configuration.
- Battery and charging: a cell or pack, suitable charging and protection circuitry, and regulated power for the system and peripherals.
- Controls: buttons, a D-pad and, if wanted, analog sticks, connected directly or through a microcontroller.
- Audio: an amplifier and speakers, with a headphone connection if required.
- Cooling and enclosure: a thermal solution and a case that fits the board, screen, battery and controls.
Raspberry Pi lists CM4 configurations with 1GB, 2GB, 4GB or 8GB of RAM, and with 0GB (Lite), 8GB, 16GB, 32GB or 64GB of eMMC storage. Wireless options also vary by SKU. Choose the exact module before planning storage and software installation: a Lite module has no onboard eMMC, while an eMMC model has onboard flash.
Choose a carrier before designing the case
The CM4 IO Board is useful for prototyping because it exposes the module’s connections without requiring a custom PCB. Raspberry Pi documents 5V GPIO or 12V barrel-jack input, two HDMI connectors, two MIPI DSI display connectors, two USB 2.0 connectors, a micro-USB upstream port, Gigabit Ethernet, PCIe, GPIO and a fan connector on the board. That access makes it easier to bring up the system and diagnose wiring or software problems, but a development board is usually less convenient to package in a handheld than a smaller custom carrier.
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- Upgraded processor BCM2711, quad-core Cortex-A72 (ARM v8) 64-bit SoC, more powerful performance
- Faster eMMC Flash storage, up to 100 MBytes/s data rate, which is four times faster than the CM3+
- Adopts B to B connectors, more stable than the Goldfinger edge connector of previous generations
- Onboard new Gigabit Ethernet PHY supporting IEEE1588, suitable for network applications
- Onboard new PCIe Gen 2 x1 interface, allows connecting more useful modules
| Carrier approach | Useful for | Trade-off |
|---|---|---|
| CM4 IO Board or another development carrier | Initial boot, display tests, networking, USB peripherals and hardware debugging | Offers less flexibility for a compact enclosure than a purpose-built board |
| Custom compact carrier PCB | Integrating only the connections and components needed by the finished handheld | Requires the electrical interfaces and mechanical dimensions to be settled before layout |
Start on a development carrier unless you already have a validated design. Confirm that the exact CM4 SKU, carrier, display and power arrangement are compatible before ordering parts.
Select and validate the display
HDMI is a straightforward way to get an early prototype on screen. A MIPI DSI panel can be more directly integrated, but requires a compatible connector, the correct cable and supported software configuration. Raspberry Pi documents connecting a compatible panel to DISP0/DSI0 or DISP1/DSI1 using a 22-pin-to-15-pin display adapter. For its documented 7-inch display overlay, the configuration line is dtoverlay=vc4-kms-dsi-7inch; reboot after applying the configuration.
Do not assume that a panel will work because its size or connector appears to match. Check the panel’s pinout, voltage, driver support and cable before connecting it. Compare candidate screens on:
Rank #2
- 8GB RAM; 32GB eMMC Flash with WIFI
- Upgraded processor BCM2711, quad-core Cortex-A72 (ARM v8) 64-bit SoC, more powerful performance
- More options for RAM (1GB/2GB/4GB/8GB), competent for large-scale data compilation
- Faster eMMC Flash storage, up to 100 MBytes/s data rate, which is four times faster than the CM3+
- Option for fully certified radio module, the same one used on Pi4B, supports either PCB trace antenna or external antenna, more suitable for industrial applications
- Diagonal size, resolution and refresh rate
- Brightness and viewing angle
- Whether touch input is needed
- Connector type, cable routing and available enclosure depth
- Power draw, particularly the backlight’s contribution to runtime
A 5–7-inch panel is a practical range to investigate for a handheld with physical controls, not a compatibility guarantee. The Retro Lite CM4 reference used a 5.5-inch LCD.
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Plan controls and audio around the carrier
Decide early whether buttons and sticks will connect directly to GPIO or be read by a separate microcontroller. Direct GPIO can avoid an additional controller, while a microcontroller can handle button scanning, analog-stick input, safe-shutdown signaling or battery-gauge reporting. It also adds firmware work, wiring and another power consumer, so test the complete input path before finalizing the board.
Allow for the audio hardware in both the electrical design and enclosure. The Retro Lite CM4 reference included stereo speakers, a headphone jack with automatic switching and an I2S WM8960 audio amplifier. Those are implementation examples rather than required parts; select audio components that match the chosen carrier and the space available in the case.
Rank #3
- Upgraded processor BCM2712, quad-core Cortex-A76 64-bit SoC, more powerful performance
- Faster eMMC Flash storage, up to 200 Mbps data rate
- Adopts B to B connectors, most compatible with Compute Module 4
- Onboard Gigabit Ethernet PHY supporting IEEE1588, suitable for network applications
- Onboard PCIe Gen 2 x1 interface, allows connecting more useful modules
USB planning matters too. In the Retro Lite design, the CM4’s single USB connection was occupied by an Arduino control input, so its makers added a USB hub for other devices. Account for every internal and external USB device when choosing a carrier and routing connections.
Design the battery, charging and thermal system together
Work out the power tree before you settle the enclosure. Battery chemistry and cell count determine what charger, protection circuitry and voltage conversion are appropriate. Provide a controlled shutdown path so the system can close down cleanly when power is low; abruptly losing power can increase the risk of filesystem corruption.
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Estimate and then measure consumption with the actual configuration. Include the display backlight, processor under emulator load, audio amplifier, USB devices and fan. Runtime depends on the battery, brightness, workload, volume, temperature and conversion efficiency, so capacity alone cannot establish how long a finished console will run.
Rank #4
- The power of Raspberry Pi 4 in a compact form factor for deeply embedded applications. Raspberry Pi Compute Module 4 incorporates a quad-core ARM Cortex-A72 processor, dual video output, and a wide selection of other interfaces.
- Raspberry Pi Compute Module 4 4GB RAM 0GB (Lite) CM4104000 comes with Gigabit Ethernet, 2.4GHz and 5.0GHz IEEE 802.11b/g/n/ac wireless, Bluetooth 5.0, BLE, with onboard and external antenna options.
- H.265 (HEVC) (up to 4Kp60 decode), H.264 (up to 1080p60 decode, 1080p30 encode),Energy-efficient Raspberry Pi runs silently and uses far less power than other computers.
- Broadcom BCM2711 quad-core Cortex-A72 (ARM v8) 64-bit SoC @ 1.5GHz,more powerful than earlier models.
- Package Includes: 1x Raspberry Pi Compute Module 4 CM4104000 4GB RAM 0GB (Lite) Single Board,1x Aluminum Alloy CNC Heat Sink with PWM Fan for Raspberry Pi CM4 Module
Cooling is also part of the packaging decision. The Retro Lite CM4 used a custom copper heatsink and fan. Whether a particular build needs active cooling depends on its design and operating conditions; validate thermal behavior under the workload you intend to use rather than treating a video-decoding specification as proof of emulator performance.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the Retro Lite CM4 shows—and what it does not
In Raspberry Pi’s report dated 28 March 2022, the Retro Lite CM4 build used a 5.5-inch LCD, a 4000mAh battery, a custom control and audio PCB, a copper heatsink and fan, and a USB hub. Its makers reported about four hours of battery life and full-speed Dreamcast and PSP emulation on that completed console.
Those are results for that particular build, not guaranteed outcomes for another CM4 handheld. The report does not establish performance or runtime across CM4 configurations, games, emulator settings, displays or battery designs. Raspberry Pi’s CM4 datasheet lists H.265/HEVC decode up to 4Kp60 and H.264 video capabilities, but video decoding specifications do not by themselves predict how well an emulator will run. Emulator software, settings and thermal limits also matter.
Bring up the prototype in stages
- Select the CM4 SKU. Decide how much RAM you need and whether to use a Lite module with removable storage or a module with the required eMMC capacity. Check whether the chosen SKU includes the wireless options your project requires.
- Boot on a development carrier. Use a CM4 IO Board or compatible carrier to verify boot, networking and USB before designing a custom board or enclosure.
- Test the display connection. Validate the chosen HDMI or DSI panel, cable and any required overlay configuration. Confirm the screen is stable before integrating it mechanically.
- Add controls and audio on the bench. Test buttons, sticks, amplifier, speakers and headphones, including any microcontroller or USB hub in the design.
- Integrate power and cooling. Add the correctly matched battery, charging and regulation hardware, then test controlled shutdown, current draw and thermal behavior under an emulator workload.
- Design the compact carrier and enclosure. Once the interfaces, component choices and physical dimensions are stable, move from the development setup to a custom layout intended for the handheld.
Install software and add games legally
Raspberry Pi Magazine describes installing RetroPie and enabling its Samba share so files can be copied over the network to ~/RetroPie/roms. Installation steps and package support can change, so check the current RetroPie and Raspberry Pi documentation for the software versions and setup method you plan to use. Obtain game files legally; a network share provides a transfer method, not permission to copy or use a game.
Batocera and other distributions may be alternatives, but CM4-specific support details are not established here. Verify current support for your exact module, carrier, display and controls before choosing an image.
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