My Raspberry Pi system is nearing completion. After two weeks of planning and designing the proper layout for this compact configuration, I fabricated a custom metal case out of 20-gauge sheet metal and 1/8-inch polycarbonate. The system uses a Raspberry Pi 5 16GB along with multiple Waveshare hardware components to achieve my desired setup.
The goal is to build a multifunctional desktop computer that provides 5G broadband for home internet using my homemade 36-inch parabolic MIMO 5G dish antenna, aimed at a T-Mobile tower 3.5 miles away. I will also use it as a media server, cloud storage device, VPN gateway, retro gaming system, APRS station, software-defined radio, LoRa Meshtastic node, and for several other functions.
Stacking several hardware components directly on the GPIO pins would have been unrealistic. Not only would it fall short on power delivery and create an absurdly tall stack, but it would also lack any proper enclosure for long-term use. Instead, I designed what I call the “PCIe HAT (hardware on top) Cluster” — a divorced mounting system that securely holds the PCIe-driven HATs behind the Pi on their own custom bracket. This approach allows me to add nearly as many HATs as needed while orienting the connectors toward the front of the case for easy access. I’m currently using the Waveshare PCIe M.2 4G/5G USB 3.2 HAT with the Quectel RM520N-GL module, along with a Realtek Wi-Fi module on an E-Key HAT.
The PCIe HAT cluster orients the HATs back-to-back and flipped 90 degrees vertically from their normal position. The four-channel PCIe adapter is mounted slightly offset so I can use short 40mm PCIe ribbon cables to each HAT. Power for the upper stack is supplied through its own dedicated circuit from the Mean Well PSU, injected directly into the GPIO header of the 5G HAT using two 5V pins and multiple ground pins. I also ran GPIO5 and GPIO6 from the Pi to the cluster so I can control power and reset of the RM520N-GL module. The entire cluster has room for up to four PCIe HATs and includes space for future Pi Zero-sized expansion boards.
Cooling comes from a 40mm LED intake fan pulling fresh air directly through the vertical stack, supplemented by the large Geek Pi active cooler on the Pi 5 itself. For the rear panel, I used the Waveshare HDMI adapter board to bring both HDMI ports and power connections flush with the Pi’s native ports. The cutouts are neatly covered by a thin polycarbonate bezel I made from a welding hood replacement lens.
On the back I have the Pi’s native USB and Ethernet ports, dual HDMI, six SMA connectors for external antennas, an IEC C14 power inlet, and the main power switch. The front features the 5G HAT’s USB 3.2 ports and a momentary push-button connected to the Pi’s J2 reset pads.
Power comes from a Mean Well 50W 5V supply set to 5.15V to give headroom against voltage drop. I’m currently running dedicated feeds to the Pi and the HAT cluster, and I plan to add proper blade fusing along with dual MOSFET switches so the fans and HATs can be cleanly depowered when the Pi shuts down.
My 5G setup uses a repurposed 36-inch HughesNet dish with a custom-built 4×4 MIMO feedhorn tuned for the n77 band. Four runs of LMR-240 coax connect to the case, giving me a strong, unobstructed shot at a T-Mobile tower 3.5 miles away.
This first assembly was mainly to test whether my unconventional layout would even work. So far everything has powered up and functioned as intended on the first try, which feels like a big win. I still have several tasks left, including installing the blue LED fans, finishing the fused wiring harness, adding the MOSFET shutdown control, mounting the final polycarbonate panels, and cleaning up the bezel. I’m debating whether to paint the case or just apply a clear coat to keep the raw cold-rolled steel look.
This system should make an excellent always-on home server while I develop the next version — a more compact build for my Jeep using a 12V-to-5V buck converter. That one will integrate with an Arduino running Speeduino for engine management while the Pi handles the multimedia system, digital dash, live tuning, and a full Wi-Fi mesh network for group off-road trips.
The mesh network will let vehicles stay connected across remote areas, with offline maps, encrypted chat, push-to-talk, shared GPS tracks, and SOS alerts. It’s an ambitious project, but this desktop version is proving the core hardware concept works.
Keep a lookout for a future article detailing my Jeep PC.
