What's the best Android app for turning an old smartphone into a security camera?

Surveillance Camera stands out as a practical solution for converting an old Android device into a dedicated security camera or baby monitor. Its primary appeal lies in the dead-simple setup process, which uses QR codes to pair camera and viewer devices on the same Wi-Fi network within moments. This eliminates the frustration often associated with DIY camera systems. Once configured, the app delivers a consistently clear live video feed. A key feature is its reliable background operation, allowing the 'camera' phone to continue streaming even when the screen is off, which is essential for prolonged monitoring. Users also benefit from immediate motion and sound alerts, enabling quick response to activity. The app performs well on older hardware, maximizing the utility of otherwise retired smartphones. However, its functionality is primarily local and peer-to-peer, so advanced features like cloud storage or multi-camera grids found in dedicated security systems are absent. For anyone seeking a cost-effective, zero-subscription way to keep an eye on a room, pet, or front door, Surveillance Camera delivers a robust and user-friendly experience that justifies its high user ratings.