Turn Old Samsung Galaxy Phones into Smart Home Sensors
Old Galaxy phones often end up in a drawer, their useful hardware forgotten long after the next upgrade arrives. In 2026, Samsung’s Galaxy Upcycle program offers a smarter alternative: turning those retired devices into privacy-friendly smart home sensors. A Galaxy S9, Note 9, or newer model can detect sound or light, send alerts, and trigger automations through SmartThings. Why let a perfectly capable Galaxy S10 become e-waste when it can function as a dedicated baby monitor or a room brightness sensor?
How Galaxy Upcycle Works
At its core, Galaxy Upcycle uses an old phone’s microphone and light-sensing abilities to create a wireless sensor for SmartThings. The camera remains off, and all recognition is processed locally on the device. Samsung does not record video or stream audio to its servers. This design keeps the feature responsive while reducing privacy concerns.
The feature works with a Galaxy S9, Note 9, or a newer Samsung phone used as the sensor. The receiving device can be any current Galaxy phone with the SmartThings app, such as the Galaxy Z Flip 6 or a newer model. Both devices need to be signed into the same Samsung account; otherwise, the sensor will not appear in the main device’s device list.
Setting Up a Retired Galaxy as a Sensor
The setup process is straightforward. First, update the old phone to the latest available Android version through Settings → Software Update. On the primary phone, install or update SmartThings from the Galaxy Store or Play Store.
After the basics are handled, follow these steps:
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Open SmartThings on the primary phone.
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Tap the Menu button, then select Labs.
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Tap Galaxy Upcycle and continue through the instructions until a QR code appears.
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Use the old Galaxy phone’s camera to scan the QR code.
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Download and open the Galaxy Upcycle app from Galaxy Store.
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Grant the requested permissions, especially microphone access for sound detection.
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Choose whether the phone will work as a light sensor, sound sensor, or both.
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Assign a location and room, such as “Baby’s Room.”
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Connect the old phone to power. The Upcycle app limits charging to 35 percent to protect battery health.
Once the setup is complete, the new sensor appears under the Devices tab in SmartThings. From there, a user can turn it on or off, view detection timelines, and adjust sensitivity and volume settings.
What the Sensors Can Detect
The sound sensor is not just a simple noise meter. It can recognize specific sound events, including baby crying, dog barking, cat meowing, glass breaking, door knocks, sirens, finger snapping, and snoring. Each type can trigger a different automation. Isn’t that more useful than receiving a generic alert every time the room gets loud?
The light sensor measures luminance on a scale from 1 to 7. That makes it possible to automate lighting based on actual room brightness instead of relying on sunset times or fixed schedules. For example, a lamp can switch on only when a room becomes perceptibly darker.
| Sensor mode | What it detects | Common uses |
|---|---|---|
| Sound sensor | Baby crying, dog barking, cat meowing, glass breaking, door knocks, sirens, finger snapping, snoring | Baby monitoring, security alerts, pet notifications |
| Light sensor | Luminance levels from 1 to 7 | Brightness-based lighting automation |
A Practical Baby Monitor Setup
A popular use case places an old Galaxy S10 in a nursery. The phone listens for crying, and when the sound is recognized, it sends an instant notification to the current Galaxy device. The automation can also turn on a soft light in the room. The user can listen and respond wirelessly from the SmartThings app.
One important advantage is that the devices do not need to be on the same Wi-Fi network. As long as both phones have an internet connection, alerts arrive normally. This makes the system suitable for remote monitoring.
Battery Health and Daily Use
Leaving a phone plugged in around the clock can degrade its battery, but the Galaxy Upcycle app is designed with this in mind. During active use, it limits charging to 35 percent. After months of continuous operation, an older Galaxy S10 can remain cool and stable, with no noticeable overheating issues. That controlled charging strategy makes the old phone far more suitable as an always-on sensor.
Conclusion
For anyone who already uses SmartThings, repurposing an old Galaxy phone is essentially a free smart home expansion. The microphone and processing power in a retired flagship often exceed what many dedicated smart home sensors offer. Instead of letting a drawer full of Galaxies collect dust, a user can turn them into capable baby monitors, security listeners, or light meters. Isn’t a no-cost smart home upgrade better than another obsolete device sitting unused?