Overview
We all know that there is nothing more infuriating than forgetting where we placed something important or misplaced things. Losing your keys, wallet, or other valuable items can be a frustrating experience. Apple recognised this common problem and introduced the AirTag, a small, Bluetooth-enabled device that helps you keep track of your belongings. By attaching an AirTag to your items, you can easily locate them using the "Find My" app on your iPhone. The AirTag sends a secure Bluetooth signal that nearby devices in the Find My network can detect, allowing you to see the item's location on a map. Inspired by the functionality and usefulness of Apple's AirTag, we created a DIY solution that brings similar benefits with a personal touch. This project involves creating your own Bluetooth Low Energy (BLE) air tag/key finder that will help you keep your important things safe.
The heart of this project is an MDBT50Q-1MV2 BLE module from Raytac featuring an nRF52840, an ultra low power BLE SoC from Nordic with a 32-bit ARM Cortex-M4 core running at 64MHz. An ADXL345 3-axis accelerometer from Analog devices is also included in the circuit to detect movement. Multiple LEDs and an active buzzer are provided for visual and audible indications. The whole circuit is powered by a 3V CR2032 lithium battery. The key finder function can be used to find the Airtag which the Airtag will output a loud alarm along with LED indications, which makes it easier to find it in both bright and dark environments. With loss prevention mode enabled the Airtag will sound the Alarm and LED indications as soon as the Airtag is disconnected from the smartphone.
Components Required
| Value | Manufacturer | Digikey Part Number | Datasheet Link | Quantity |
|---|---|---|---|---|
| CR2032 | Adam Tech | 2057-BH-74B-5-ND |   | 1 |
| SMT-0540-S-R | PUI Audio | 668-1060-1-ND | | 1 |
| 7pF | Murata Electronics | 490-5878-1-ND | | 2 |
| 10uF | Manufacturer | 490-GRM155R60J106ME05DCT-ND | | 4 |
| LED Red | Harvatek Corporation | 3147-B1911USD-20D000114U1930CT-ND | | 1 |
| LED Blue | Harvatek Corporation | 3147-B1911NB--20C005314U1930CT-ND | | 1 |
| 1N4148WS | Diotec Semiconductor | 4878-1N4148WSCT-ND | | 1 |
| ADXL345BCCZ | Analog Devices Inc. | 505-ADXL345BCCZ-ND | | 1 |
| NFC ANT | Taoglas Limited | 931-FXC.16.A-ND | | 1 |
| S8050 | Micro Commercial Co | MMSS8050-L-TPMSCT-ND | | 1 |
| 1k | Panasonic Electronic Components | P1.00KLCT-ND | | 3 |
| 27R | Panasonic Electronic Components | P27.0LCT-ND | | 2 |
| 10k | Panasonic Electronic Components | P10.0KLCT-ND | | 2 |
| MDBT50Q-1MV2 | Seeed Technology Co., Ltd | 1597-1678-ND | | 1 |
| 32.768KHz | Abracon LLC | 535-9543-1-ND | | 1 |
