Know before your wine does.
Cava Guard watches the temperature inside your wine fridge and tells your iPhone the moment something is wrong — including when the sensor itself goes quiet.
Cava Guard is the iPhone client for a small monitoring server that runs on your own Raspberry Pi, with a Zigbee temperature sensor inside the fridge. Without that server the app has nothing to show you. Everything you need is on the setup page.
What it does
- Live temperature from every sensor, and the history behind it — six hours to a year, with the highs and lows each reading hides.
- Alerts that break through. Set a range per fridge; going outside it sends a time-sensitive notification that Focus does not hold back.
- Alerts on silence. A sensor that stops reporting raises an alarm of its own. A monitor that fails quietly is worse than no monitor.
- Battery and signal for each sensor, so a dying cell is something you replace rather than discover.
- More than one place. A fridge in another house is just another server in the list; alerts arrive from all of them.
What it does not do
- No cloud. Readings go from the sensor to your Pi and from your Pi to your phone. There is no service in the middle, because there is no service.
- No account. Nothing to sign up for. Nothing to sign in to.
- No subscription, no ads, no analytics. The app is free and collects nothing. See the privacy policy — it is short, because there is little to say.
What you need
| Raspberry Pi | A Pi 4 or newer, on your home Wi-Fi. It runs the monitoring server and keeps the history. |
|---|---|
| Zigbee coordinator | A USB stick — a SONOFF ZBDongle-E or -P. About €16. |
| Temperature sensor | A SONOFF SNZB-02P or similar, inside the fridge. ±0.2 °C, and the battery lasts years. About €13. |
| An iPhone | iOS 18 or later. |
Roughly €75–95 all in, most of it the Pi. The setup guide walks through it.
Away from home
The app talks to your Pi directly on your own network. To reach it from anywhere else it uses Tailscale, which you turn on from inside the app — no ports opened on your router, no dynamic DNS, and a real certificate. Nothing about your fridge is ever exposed to the internet.