Rewind home camera
“Ok Google, keep the last thirty seconds.”
The most precious, unpredictable moments with young children always happen when no one is holding a camera. To eliminate that recurring frustration of "I wish I was recording that!", I built an indoor camera that retrospectively saves video from the past 30 seconds using a simple voice command.
Why
Living with small kids means memorable moments arrive without warning: a funny quote, a silly dance, or a major milestone. By the time you reach into your pocket, unlock your phone, and open the camera app, the moment has already passed. Walking around with a phone constantly pointed at your family isn't an option—I needed a way to record after the fact.
How It Works
I mounted a Raspberry Pi equipped with a camera module in the living room.
- Rolling 30-Second Buffer: Much like a dashcam, it continuously captures video in short segments, keeping only the most recent 30 seconds and automatically overwriting older footage. This avoids filling up local storage while minimizing the psychological discomfort of being under constant 24/7 surveillance.
- Voice Trigger: When something memorable happens, anyone can simply say to our living room Google Home: "OK Google, save that." The command triggers ffmpeg to stitch the buffered segments into a single video file and export it automatically.
In Use
It fulfilled its purpose of rescuing candid, everyday moments without making anyone self-conscious about a lens.
Just as I shared in the original tweet, it successfully captured that exact moment when my child reached out and fed themselves a snack for the very first time.