In short: When a fall is detected the app will send an SMS to the configured emergency phone number.
- Make sure to configure the emergency phone number for the app to call automatically when a fall is detected.
- Calls from that number will be answered automatically.
- An SMS from that number with the word POSITION in the content will be replied to automatically with the geographical position (if available).
- If the SMS contains the word ALARM instead, it will play back an alarm sound.
- The app will start automatically when the phone is turned on.
- For optimal performance (to reduce the number of false alarms and the number of undetected falls) carry the device close to your waist (a trouser pocket, a belt clip, etc.).
- Keep your device charged at all times.
Install the app by side-loading the APK file available here (you can find more info about the process here).
If you are familiar with F-Droid repositories you can also use the following link:
| EULA screen (MIT license) | About view (with instructions & emergency button) | Sensor & detection signals view (pausable & zoomable) | Settings view (to set emergency number & data collection) | Emergency number editor (with contact book lookup) |
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The fall detection is based upon the algorithm number 2 described in "Comparison of low-complexity fall detection algorithms for body attached accelerometers" authored by Maarit Kangas, Antti Konttila, Per Lindgren, Ilkka Winblad, Timo Jamsa and published in Gait & Posture 28 (2008) by Elsevier (search for the paper here)
The 2010 app was written in Java & C (both integrated via JNI and Android NDK) but I decided to port it to Kotlin to learn the language on a practical example. A couple of other aspects had to be updated too, including: permissions, image assets, deprecated APIs, theme, action layouts, Gradle files, etc.
The app also allows to collect & share sensor data on IPFS for research purposes (it uses IPFS HTTP client, rather than a full node).