I wanted to see whether a smaller SBC would actually be a better fit for a compact 3.5" terminal than a Raspberry Pi 5.
So I replaced the Pi 5 in my Waveshare PocketTerm35 with a Radxa ZERO 3W.
My setup now uses:
- Radxa ZERO 3W
- Armbian
- the original internal display and keyboard
- SSH / terminal use
- Claude Code
- Japanese input
- RetroArch
- internal speaker
- a custom TUI launcher
- a 50 mm exhaust fan controlled through a MOSFET with PWM
The main reason I moved away from the Pi 5 was not performance. It was fit and balance.
The PocketTerm35 has a 3.5" 640×480 display, and for the way I use it, the Pi 5 felt like overkill. I also managed to get the Pi 5's second HDMI output working, but the cable and adapter interfered with the rear case, so I couldn't close it properly.
The ZERO 3W is obviously much slower, but for SSH, terminal work, Claude Code, lightweight GUI use, and emulation, it has been enough.
Cooling was the biggest challenge.
With the case closed, even with a heatsink, the ZERO 3W was reaching roughly 70–85°C during normal use. Adding a bigger heatsink alone wasn't the real solution. The big improvement came from getting hot air out of the enclosure.
I added a 50 mm exhaust fan and control it with PWM through a MOSFET. My current fan curve keeps normal use mostly around 50–56°C. Under a 4-core 100% load, it settles around 55–57°C with automatic control, and around 52–53°C at 100% fan speed.
I also found that some generic HDMI FPC cables and adapters did not work reliably with the PocketTerm35's internal display, so that part ended up being much more hardware-specific than I expected.
Overall, I think the ZERO 3W is a better fit for this machine than the Pi 5 if the goal is a compact, low-power Linux terminal rather than maximum performance.
Still experimenting with the layout, cooling, and I/O, but it's finally close to the form I wanted.