Building a Sub-GHz Signal Library for Home Automation Testing

The Use Case

If you're building or debugging RF-based home automation (garage door sensors, wireless doorbell integration, RF outlet switches feeding into Home Assistant), having a organized library of known-good captured signals on Flipper turns it into a genuinely useful bench diagnostic tool, not just a one-off remote cloner.

Organizing Your Captures

Flipper stores saved Sub-GHz signals as individual .sub files under /ext/subghz/ on the SD card. Rather than relying on Flipper's on-device naming alone, connect via qFlipper (the desktop companion app) or the CLI to rename files with a consistent scheme once captured — something like doorbell_frontdoor_433.sub, outlet_livingroom_ch1_on.sub, outlet_livingroom_ch1_off.sub — future-you will thank present-you when the library grows past a dozen entries.

Folder Structure

Create subfolders under subghz/ for logical grouping — /ext/subghz/doorbells/, /ext/subghz/outlets/, /ext/subghz/garage/ — Flipper's file browser navigates these fine, and it keeps a growing library actually usable instead of one giant flat list.

Capturing Systematically

For a multi-channel RF outlet remote (common for garage/shed lighting), capture every button individually rather than assuming symmetry — on/off pairs for each channel are usually distinct signals, not just a toggle bit, and having all of them saved means you can trigger any specific state during testing without the physical remote present.

Using the Library for HA Integration Testing

If you're building a bridge between RF devices and Home Assistant (e.g. via an RTL-SDR + rtl_433, or a dedicated 433MHz receiver on an ESP32/Pi), your Flipper signal library becomes a repeatable test harness — replay a known signal from Flipper and confirm your receiving system correctly identifies and acts on it, without needing to physically press remotes during development/debugging sessions.

Backing Up the Library

Regularly copy the subghz/ folder off the SD card via qFlipper to your computer — SD cards fail, and a signal library you've spent time organizing is annoying to lose. This is also how you'd transfer signals between two Flipper devices if you use more than one.

Frequency Analyzer for Unknown Devices

For a device you don't know the frequency of, Sub-GHz > Frequency Analyzer scans across common bands while you trigger the device, narrowing down the active frequency before you switch to Read mode with the correct frequency dialed in — much faster than guessing across the full range manually.