A lot of small USB panels show up next to a PC case: 3.5 inches, 480×320 (or 320×480 portrait), one vendor app that looks like 2009. I wanted temperatures, watts, and the song that's playing, set in type, not in a dashboard full of gauges.
So I built PanelOS: a Windows tray app that draws on that panel and stays out of the way.
The canvas is tiny
480×320 is closer to a phone from 2012 than to a monitor. Every pixel matters:
- One dirty rectangle per second for live values (CPU/GPU load, temps, power). No full-frame redraws for a number that moved by one degree.
- Album covers load as a full frame only when the track changes, then crossfade. Bright covers get a stronger scrim so white text stays readable.
- Themes switch on the next frame from the tray, no restart, no splash.
The default look is Signature: full-bleed album art fading into a dark left plate, huge thin numerals, one RAM | VRAM | FAN line, and the track with a progress bar. Covers come from iTunes Search (with a cleaned Windows media thumbnail as fallback). No Spotify logo on the panel.
Six themes, one tray
Besides Signature there is Nature Flow (stats over a quiet wallpaper slideshow), Noir Editorial, Gallery, Chronograph, and Classic. Landscape or portrait, your accent color, start-with-Windows with a short USB delay.
Lite is free: Classic only, no now-playing. Pro is a one-time $15.99 for all themes, Spotify now-playing, two PCs, and every 1.x update. No subscription, no account.
Sensors and USB without drama
CPU package temp and fan RPM need admin once (the installer sets that up). Without it the panel still runs; those values just read zero. Confirmed panels are the common 3.5″ devices with Hardware Id VID_1A86&PID_5722, check Device Manager before you buy a random listing (compatible screens checklist).
The USB side of "make this gadget speak without the vendor app" is its own rabbit hole. While working on panel protocols I also open-sourced usb-rea: capture labelled clicks from a Windows vendor app, diff the packets, and get a report (every claim cites Wireshark frames) plus a starter pyusb driver. PanelOS is the product; usb-rea is the tool that made the reverse-engineering loop less painful.
What's live today
- Free Lite: download the installer (Windows 10 and 11). Pro unlocks in the same app with a key in Settings → License.
- Pro: PanelOS Pro on Gumroad, $15.99 one-time
- Site + help: PanelOS with a help hub: setup, device not connected, CPU temp shows 0, themes, Spotify / now playing, and Windows SmartScreen
- Contact form on the site for support
One honest note: the installer isn't code-signed yet, so Windows may show a SmartScreen warning the first time. The SmartScreen page explains what you'll see.
If you own a matching 3.5″ USB panel, try Lite first; if it runs on your screen, Pro is the same app with everything unlocked. If you're reverse-engineering a different gadget, start with usb-rea and open an issue with a capture.
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