Baby Monitor

A baby monitor is a camera pointed at a sleeping child, left running all night. The category has spent a decade moving that stream into manufacturers' clouds, where it is an account breach away from strangers — and the stories that follow are the worst kind.

Dedicated hardware is the other option: a second screen to charge, a device that stops getting firmware updates, and a picture worse than the phone already in your pocket.

Install the app on two or more devices and pair them by scanning a code while both are on the same WiFi. From then on they recognise each other using encryption keys created on the devices themselves, held in secure hardware where the device provides it, and never sent anywhere.

Video and audio travel directly between your devices over WebRTC, encrypted with DTLS-SRTP, and are never recorded. Sound level is measured on the nursery device itself, so alerts work without any audio leaving the room.

Watching from outside the house is the only time anything of ours is involved: a small connection service helps two of your devices find each other, then steps out of the way. It sees a random device number, a public key and an IP address — never a picture, a sound, or anything from the log.

The nursery device keeps a log of feeds, sleep and nappies, and can suggest naps from the routine it has seen. You can record video messages for your child to play in the room, leave notes for a babysitter, set a night light, and give a sitter access that expires after a set number of hours.

A Bluetooth thermometer, if you have one, adds room temperature and humidity. All of it stays on your family's devices: Android's cloud backup is switched off for the app, so none of it is copied to a Google account, and uninstalling removes it.