Anti-theft alarm for bags

Two devices that travel with you and with your bag and watch each other over Bluetooth: if they drift too far apart or someone takes the bag, both trigger an alarm. Ultra-compact and low power.

Anti-theft Bluetooth (BLE) Ultra-compact
How it works What we built
In pairs you carry one device and the other stays in the bag
Bluetooth they watch each other with no need for coverage
Low power deep sleep to last on a small battery

The problem: slip-ups and snatches

A bag gets left on a chair or snatched in a second; by the time you notice, it’s already too late.

You can’t watch it every second

In busy places —terraces, transport, events— it’s impossible to keep an eye on the bag all the time.

By the time you react, it’s gone

Without an instant alert, the slip-up or theft is discovered when the bag is already far away.

How it works

Two paired devices that alert you the moment something goes wrong.

Two paired devices

You carry one and the other stays in the bag; they communicate over low-power Bluetooth.

Alert when they separate

If the distance between them exceeds the configured level, both trigger a deterrent audible alarm.

Alert if one turns off or is lost

If one disconnects or powers off, the other starts beeping within a few seconds.

You stay in control

From your device you can silence the alarm, and the sensitivity can be tuned to your liking.

Pair of anti-theft bag alarm devices in 3D-printed housings
The finished devices: ultra-compact pairs in 3D-printed housings.

What we built

From concept to working prototype, end to end.

Ultra-compact hardware

Custom PCB and 3D-printed housing designed to fit any bag without getting in the way.

Firmware

Bluetooth pairing, distance detection by signal strength (RSSI), button control and alarm management.

Low power

Deep sleep and critical battery management to squeeze out the runtime.

Tuning and certification

Mobile app to set the sensitivity, tamper detection and readiness for CE/FCC certification.

Technology

The whole stack, from the chip to the app.

  • ESP32 microcontroller
  • Bluetooth (BLE)
  • Distance detection by RSSI
  • Alarm buzzer
  • Deep sleep (low power)
  • Configurable sensitivity
  • Tamper detection
  • Custom PCB
  • 3D-printed housing
  • iOS / Android app
  • CE/FCC readiness

End-to-end development by RobotUNO

From concept to product: custom electronics, Bluetooth firmware and a 3D-printed housing. Have a similar project?

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