Kaaka Sensors

Kaaka Sensors is the optional app for the caller's own phone. It gives them an SOS button, fall detection, a safety timer and an "I'm safe" button, and sends GPS reports to the Kaaka number by SMS.

Install and set up

1. Install client/KaakaSensors.apk on the caller's phone, not on the Kaaka number.
2. Open it and allow what it asks for: SMS, phone, location including "Allow all the time" (reports go out while the app is in the background), notifications, and activity recognition for the pedometer.
3. In the Settings card enter the gateway phone number: the Kaaka number. This is the only number that can start the beacon and the only number reports are sent to.
4. The app offers to become the default SMS app. That is what lets it react to the Kaaka reply reliably and show the full-screen alert. It is optional for the SOS button.

The two computer settings (dashboard WebSocket and live sensor stream URL) are extras for a dashboard on the same Wi-Fi. Kaaka Sensors works phone-to-phone with only the gateway number.

What starts the beacon

• The Kaaka reply. When the caller phones the Kaaka number and the reply SMS arrives from the configured number, the app sends a "Kaaka Alert" report with a fresh GPS fix straight away, then keeps reporting. An SMS from any other sender does nothing, whatever it says.
• SOS button at the top of the main screen: one report now, then the beacon.
• Auto SOS on fall (off by default): an acceleration spike above about 2.5 g followed by two seconds of stillness starts a 15-second countdown with an "I'm OK, cancel" button. The thresholds are untuned; expect false alarms until tested on real phones.
• Safety timer: pick 15 min, 30 min, 1 h, 2 h or a custom length. Tap I'm safe to check in, or Extend +15 min. If it runs out, a 30-second countdown starts, then SOS. The deadline is stored, so a timer that ended while the app was closed counts down as soon as the app reopens.

Only one countdown runs at a time, and pressing SOS during a beacon sends one extra report rather than starting a second beacon.

The beacon

Reports go to the Kaaka number every 60 seconds by default. The Update every control offers 15, 30 or 60 seconds; the control room draws the reports as a trail on the map. The beacon stops by itself after the configured duration (30 minutes by default) or when you tap Stop. The SOS card shows the trigger, how many reports were sent, the last send time and the minutes left.

I'm safe

While the beacon runs or a countdown is active, the I'm safe — close my alert button stops the beacon, cancels any countdown and timer, and texts SAFE to the Kaaka number. The Kaaka number closes the incident, confirms to the caller and tells responders. The button shows whether the SMS actually went out.

What a report contains

Kaaka Alert: Emergency assistance requested

Live Sensors (5/5):
• Pedometer: 120 steps (0.09 km)
• Light: 53 lx
• Accelerometer: 9.7 m/s²
• Gyroscope: 0.2 rad/s
• Magnetometer: 186° S
• Coords: 10.007040, 76.365610
• Maps: https://maps.google.com/?q=10.007040,76.365610
• Trigger: sos

Without a GPS fix the report says • Location: unavailable; the first report goes out after at most five seconds either way, and later ones carry coordinates once GPS locks. Triggers are sos, fall, safety timer, gateway reply or manual.

Limits

• Fall detection, the safety timer and the beacon run inside the app. With the app closed or the screen off for a long time, Android may pause them. Keep the app open during an emergency.
• Reports are SMS from the caller's own SIM and cost the same as any SMS.
• On Xiaomi and other heavily customised phones, grant the permissions inside the app's setup card and turn off battery restrictions for Kaaka Sensors; see Troubleshooting.

Kaaka 1.0.0 · Edit this page · In immediate danger, call 112.