Raspberry Pi RP2040
Pocket Cyberdeck Retro Handheld
Overview
A pocketable handheld cyberdeck featuring advanced connectivity, retro gaming capabilities, and all-day battery life in a rugged 3D-printed enclosure.
Makise KurisuSystem architecture
POWER
MODULE
MCU
DISPLAY
RF
- POWER_MGMT → SBC_COREPowerMain system power rail
- SBC_CORE → DISPLAY_TOUCHUSBDisplay pixel data and touch controller I2C
- SBC_CORE → KEYBOARD_MCUUSBKeyboard HID data link
- SBC_CORE → ETHERNET_PHYUSBSecondary Ethernet controller PCIe/USB bus
- SBC_CORE → CELLULAR_4GUSBModem data and AT command channel
- SBC_CORE → SDR_FRONTENDUSBHigh-speed IQ sample data stream
Bill of materials
| Part number | Type | Component | Manufacturer | Package | Qty | Datasheet | Match |
|---|---|---|---|---|---|---|---|
| TPS65987DCGRSHR | POWER | TI BQ25713 Multi-Cell Li-ion Battery Charger & TPS65987D USB-PD Controller Manages multi-cell Li-ion battery pack charging, power path switching, and fast-charging protocols. | Texas Instruments | Bulk | 1 | Matched | |
4 alternatives consideredAI verified | |||||||
| CM4 | MODULE | Raspberry Pi Compute Module 4 (CM4) Main application processor running Linux for retro gaming, media, and system orchestration. | Gardner Bender | — | 1 | Matched | |
| RP2040 | MCU | Raspberry Pi RP2040 Scans custom ortholinear mechanical switch matrix and bridges via USB to the main SBC. | Raspberry Pi | QFN-56 | 1 | Matched | |
1 alternatives consideredAI verified | |||||||
| X1920-A | DISPLAY | 5.5-inch MIPI-DSI IPS Touch Display (1080x1920) Provides visual output for retro gaming, media consumption, and terminal UI. | BOURNS | — | 1 | Matched | |
1 alternatives consideredAI verified | |||||||
| LAN7800/ML | MODULE | Microchip LAN7800 (USB 3.0 to Gigabit Ethernet) + Integrated MagJack Implements dual Ethernet ports alongside the native SoC MAC/PHY. | Microchip | — | 2 | Matched | |
3 alternatives consideredAI verified | |||||||
| EG25GGB-MINIPCIE | RF | Quectel EG25-G Mini-PCIe LTE Cat 4 Module Provides cellular 4G/LTE connectivity and GNSS positioning. | Quectel | Module | 1 | Matched | |
| RTL2832U | RF | RTL2832U + R820T2 USB RTL-SDR Tuner Chipset Enables wideband radio frequency signal reception (24MHz–1.7GHz). | REALTEK | — | 1 | Matched | |
1 alternatives consideredAI verified | |||||||
Build guide
6-8 hoursAdvanced
1
Procurement & Preparation
- Source all active components including TPS65987DCGRSHR, Raspberry Pi CM4, RP2040, X1920-A 5.5-inch display, LAN7800/ML ICs, EG25GGB-MINIPCIE cellular module, and RTL2832U SDR chipset according to the BOM list.
- Inspect the multi-layer printed circuit board (PCB) Gerbers and solder paste stencil for the main carrier board, ensuring clean pads for high-speed USB 3.0 differential pairs and MIPI-DSI traces.
- Print the rugged enclosure components using high-temperature, impact-resistant PETG or Nylon filament on an FDM 3D printer.
2
Hardware Assembly & Wiring
- Apply lead-free solder paste to the PCB using the stencil, place the TI BQ25713 charger, TPS65987D USB-PD controller, RP2040, LAN7800 chips, and RTL2832U chipset onto their respective pads, and run the board through a reflow oven.
- Mount the Raspberry Pi CM4 into its high-density board-to-board connectors on the carrier board, securing it with mechanical standoffs.
- Install the Quectel EG25-G Mini-PCIe LTE module into its slot, secure with retention screws, and attach the internal antenna pigtails for cellular and GNSS frequencies.
- Connect the 5.5-inch MIPI-DSI touch display (X1920-A) to the CM4 display port and route the I2C lines for touch input, confirming stable 5V and GND power rails.
- Assemble the ortholinear mechanical switch matrix, wire the switches to the RP2040 keyboard MCU pins, and connect the USB interface signals (USB_D+, USB_D-, 5V, GND) directly to the main SBC.
- Integrate the dual Ethernet MagJacks connected to the Microchip LAN7800 ICs, and secure all assembled electronics into the 3D-printed rugged enclosure.
3
Firmware Setup
- Flash the custom QMK or CircuitPython firmware onto the RP2040 keyboard microcontroller via USB bootloader mode to handle ortholinear key scanning.
- Flash the Raspberry Pi CM4 eMMC/SD card with a customized Linux operating system image configured with device tree overlays for the X1920-A display, LAN7800 Ethernet controllers, and RTL2832U drivers.
- Configure the TI TPS65987D USB-PD controller firmware registers via I2C/Configuration Utility to negotiate proper multi-cell charging profiles and power path switching.
4
Testing & Calibration
- Perform power-on self-test (POST) using a bench power supply with current limiting to verify there are no short circuits on the 5V, 3V3, and VBAT power rails.
- Test the 5.5-inch MIPI-DSI touch display responsiveness, color accuracy, and touch coordinate mapping across the 1080x1920 resolution.
- Validate peripheral connectivity by testing the dual Gigabit Ethernet ports, Quectel EG25-G cellular data connection, and RTL2832U wideband radio frequency signal reception (24MHz–1.7GHz).
- Run a full battery discharge and charge cycle test to verify all-day battery life performance, thermal dissipation under load, and USB-PD fast-charging functionality.
Document
Pocket Cyberdeck Retro Handheld
A pocketable handheld cyberdeck featuring advanced connectivity, retro gaming capabilities, and all-day battery life in a rugged 3D-printed enclosure.
Design Overview
| Item | Details |
|---|---|
| Product Type | Pocket Cyberdeck |
| Key Functions | Retro gaming and media consumption, Advanced wireless and physical connectivity with dual Ethernet, 4G/LTE, and SDR support, Compact mechanical keyboard input, Integrated 5-7 inch display, All-day battery management with fast charging |
| Power Source | Multi-cell Li-ion pack with fast charging |
| Connectivity | WiFi, Bluetooth, Dual Ethernet, Cellular 4G/LTE, SDR support |
| Size | Pocketable handheld, 5-7 inch screen |
| Environment | outdoor |
| Difficulty | Advanced |
| Est. Time | 6-8 hours |
System Architecture
Power Topology: Multi-cell Li-ion battery pack feeds BQ25713 charger/power-path controller, outputting regulated 5V for SBC/Display/SDR and 3.3V for PHY/Modem/Keyboard MCU.
Module List
| Module ID | Type | Name | Function | Voltage |
|---|---|---|---|---|
| POWER_MGMT | POWER | TI BQ25713 Multi-Cell Li-ion Battery Charger & TPS65987D USB-PD Controller | Manages multi-cell Li-ion battery pack charging, power path switching, and fast-charging protocols. | 7.4V |
| SBC_CORE | MODULE | Raspberry Pi Compute Module 4 (CM4) | Main application processor running Linux for retro gaming, media, and system orchestration. | 5V |
| KEYBOARD_MCU | MCU | Raspberry Pi RP2040 | Scans custom ortholinear mechanical switch matrix and bridges via USB to the main SBC. | 3.3V |
| DISPLAY_TOUCH | DISPLAY | 5.5-inch MIPI-DSI IPS Touch Display (1080x1920) | Provides visual output for retro gaming, media consumption, and terminal UI. | 5V |
| ETHERNET_PHY | MODULE | Microchip LAN7800 (USB 3.0 to Gigabit Ethernet) + Integrated MagJack | Implements dual Ethernet ports alongside the native SoC MAC/PHY. | 3.3V |
| CELLULAR_4G | RF | Quectel EG25-G Mini-PCIe LTE Cat 4 Module | Provides cellular 4G/LTE connectivity and GNSS positioning. | 3.3V |
| SDR_FRONTEND | RF | RTL2832U + R820T2 USB RTL-SDR Tuner Chipset | Enables wideband radio frequency signal reception (24MHz–1.7GHz). | 5V |
Design Schemes
Modular CM4 Carrier with Stacked Radio Hat ★
Utilizes a Raspberry Pi Compute Module 4 mounted to a custom carrier board housing dual Ethernet controllers, an M.2 cellular modem, and RTL-SDR front-end.
Trade-offs: Higher component density and slightly thicker enclosure, but preserves modular repairability and avoids high-speed signal integrity risks on a single monolithic PCB.
Single-Board SBC Integration with External USB Hubs
Integrates an off-the-shelf SBC directly with an internal USB 3.0 hub controller to fan out dual Ethernet, LTE, and SDR modules on a single cohesive PCB.
Trade-offs: Simpler board layout and lower NRE cost, but results in a slightly larger footprint and bulkier internal cable management.
Key IC selection
Multi-cell battery charger and power path controller
- Need: Manage multi-cell Li-ion pack charging and negotiate high-voltage USB-PD fast charging for a high-drain portable system.
- Class: I2C-controlled buck-boost multi-cell charger and USB-PD controller IC pair
- Shortlist: TI BQ25713 + TPS65987D, Intersil ISL9241 + Renesas RAA489000
- Pick: Select BQ25713 for robust 1-to-4 cell buck-boost charging efficiency and TPS65987D for integrated USB-PD dead-battery support.
Main application processor and system orchestrator
- Need: Provide high-performance quad-core ARM processing, native wireless, and rich peripheral interfaces in a compact form factor.
- Class: High-density LGA system-on-module with broad software support
- Shortlist: Raspberry Pi Compute Module 4, Radxa CM3
- Pick: Choose CM4 for mature mainline Linux upstream support, extensive community documentation, and reliable supply chain availability.
Cellular and GNSS positioning module
- Need: Enable global LTE Cat 4 data connectivity and location tracking over a standard Mini-PCIe interface.
- Class: LTE Cat 4 / GNSS wireless module with USB 2.0 interface
- Shortlist: Quectel EG25-G, Simcom SIM7600G-H
- Pick: Pick Quectel EG25-G for its proven Linux AT-command ecosystem, worldwide band coverage, and native Network-Control-Block driver support.
Risk register
| ID | Area | Severity | Detail | Mitigation |
|---|---|---|---|---|
| r1 | thermal | high | High thermal density inside a compact handheld shell enclosing the CM4 processor, Quectel 4G modem, and BQ25713 fast charger during heavy gaming or SDR streaming. | Design an internal copper spreader tied directly to the CM4 thermal pad and incorporate a low-profile graphite sheet along the rear chassis to dissipate heat passively. |
| r2 | emi | high | Wideband noise generated by the RTL2832U/R820T2 SDR frontend and high-speed USB 3.0 traces for the LAN7800 Ethernet PHY causing desensitization on the Quectel 4G cellular and GNSS antennas. | Apply ground shielding cans over the SDR chipset and cellular modules, route USB 3.0 differential pairs with strict 90-ohm impedance control, and keep antenna feedlines well-separated from high-speed digital buses. |
| r3 | power | med | Simultaneous high current draw spikes from cellular transmission bursts (Quectel EG25-G) and CPU load peaks (CM4) potentially causing voltage sags on the system rail. | Ensure adequate bulk capacitance (low-ESR ceramic and tantalum capacitors) near the cellular module power supply inputs and configure the BQ25713 input current limit dynamically via I2C. |
Key Components
7/7 modules matched to real parts. See the BOM tab for the full component table.
TI BQ25713 Multi-Cell Li-ion Battery Charger & TPS65987D USB-PD Controller (TPS65987DCGRSHR)
TPS65987DCGRSHR matches the primary MPN TPS65987D from Texas Instruments and is an active IC component (excluding evalua
Raspberry Pi RP2040 (RP2040)
The candidate matches the primary MPN RP2040 and is manufactured by Raspberry Pi, perfectly aligning with the module req
Build Summary
- Difficulty: Advanced
- Estimated time: 6-8 hours
- Tools required: Digital Multimeter, Reflow Oven, Soldering Iron, Precision Screwdriver Set, DC Bench Power Supply, Digital Microscope
See the Build tab for the full step-by-step assembly guide.
Generated by YuanQi AI Design System · Query: Build a portable cyberdeck computing device featuring a compact mechanical keyboard, integrated display, SBC (like Raspberry Pi CM4 or similar), battery management, and rugged enclosure.