App Pairing & User Guide

1. What the app does

The Ke_Vario app connects to your KEVario instrument and provides supporting features from your phone. The instrument handles barometric altitude, vertical speed, and audio indications. The app supplies GPS ground speed, GPS altitude calibration, and access to selected settings.

• Install the app
• Permissions
• Bluetooth connection
• Home screen data
• GPS calibration
• Device settings
• Background operation
• Troubleshooting

Chinese menu labels are included in parentheses to help you find the controls if your app interface is in Chinese.

2. Install the app

1. Open the KEVario download page on your phone, either directly or by scanning its QR code.
2. Tap Download APK (下载 APK) for Ke_Vario.
3. If Android asks about installing apps from an unknown source, allow your browser or file manager to install the APK.
4. After installation, open Ke_Vario.

The wording of installation prompts varies by phone manufacturer. If installation fails, make sure the APK has downloaded completely, then try again.

3. Allow permissions on first launch

The app may request the following permissions when you first open it. Allow them to use the corresponding features.

• Location: Provides GPS altitude and ground speed.
• Bluetooth: Allows the app to scan for and connect to the KEVario instrument.
• Notifications: Displays the ongoing background service notification.

Without the required permissions, Bluetooth scanning may fail, GPS data may stop updating, or data transmission may stop when the app is in the background or the screen is locked.

4. Enable Bluetooth on the instrument

Bluetooth may be off when KEVario starts. Enable it manually if needed.

1. Turn on the instrument.
2. Press and hold the climb-threshold button for about 3 seconds.
3. BLE appears on the display when Bluetooth is enabled.

If BLE does not appear, press and hold the climb-threshold button again and check that the instrument has sufficient battery power.

5. Connect the app to the instrument

1. Open Ke_Vario.
2. Open Settings (设置) in the bottom navigation.
3. Tap Connection settings (连接设置).
4. Tap Bluetooth device connection (蓝牙设备连接).
5. The app displays a list of devices.
6. Select KEVario-BLE.
7. Once connected, the app displays a connected status and the Bluetooth status indicator on the home screen turns green.

If KEVario-BLE does not appear, check that Bluetooth is enabled on both the instrument and your phone. Reopen the device selection screen to scan again.

6. Home screen data

The home screen shows Bluetooth and GPS status, barometric altitude, vertical speed, GPS altitude, and ground speed.

• Barometric altitude: Received from the instrument over Bluetooth.
• Vertical speed: Calculated by the instrument from air pressure, with display smoothing applied in the app.
• GPS altitude: Provided by your phone, mainly as a calibration reference.
• Ground speed: Provided by your phone’s GPS and sent to the instrument for display.

If Bluetooth disconnects, instrument readings may clear or stop updating. They resume after reconnection. GPS altitude and ground speed may be blank until the phone obtains a GPS fix.

7. Calibrate altitude using GPS

GPS calibration adjusts the instrument’s current barometric altitude to approximately match your phone’s GPS altitude. After calibration, the instrument continues using pressure changes to calculate altitude and vertical speed.

1. Go outdoors to a location with good GPS reception.
2. Open the app and wait for a GPS fix.
3. Open GPS calibration (GPS校准) in the bottom navigation.
4. Tap Calibrate GPS altitude (校准GPS高度).
5. The instrument’s barometric altitude is adjusted to the phone’s current GPS altitude.

GPS altitude can fluctuate considerably indoors. Indoor calibration is not recommended. During flight, primarily refer to barometric altitude and vertical speed.

8. Display settings

Go to Settings → Display settings (设置 → 显示设置) and select:

• Main screen (主屏幕): The instrument’s default display.
• Split-screen mode (分屏模式): Displays additional phone-assisted data when used with the app.

The instrument returns to the main screen after being switched off and on again.

9. Unit settings

Go to Settings → Unit settings (设置 → 单位设置) and select:

• Metric M (公制 M): Displays altitude in meters.
• Imperial FT (英制 FT): Displays altitude in feet.

The unit setting is saved on the instrument and retained after a restart.

10. Audio mode settings

Go to Settings → Sound settings (设置 → 声音设置) to select beep A, B, C, or D.

• A: Keeps the current default sound.
• B: A softer sound, inspired by the XC Tracer style.
• C: A more responsive sound.
• D: Inspired by the Syride style.

Selecting a mode sends the setting to the instrument and plays an audio preview covering 0–3 m/s for about 10 seconds. Selecting another mode stops the current preview and plays the new one.

The audio setting is saved on the instrument and retained after a restart.

11. Background and lock-screen operation

Ke_Vario uses a foreground service to stay active. Under normal conditions, it continues receiving GPS data, maintaining the BLE connection, and sending ground speed when the app is in the background or the screen is locked.

• GPS updates continue while the app is in the background.
• The BLE connection remains active in the background.
• Ground speed transmission continues while the screen is locked.
• Transmission stops when the app is fully closed or forcibly stopped by the system.

If you do not need ground speed during flight, you can turn off the instrument’s Bluetooth after GPS altitude calibration to save battery power.

12. Troubleshooting

KEVario-BLE does not appear

• Check that Bluetooth is enabled on the instrument.
• Check that Bluetooth is enabled on your phone.
• Check that the app has Bluetooth permission.
• Leave the device selection screen and reopen it to scan again.
• If necessary, turn your phone’s Bluetooth off and on, or restart the instrument.

GPS altitude fluctuates

This is normal, especially indoors, near buildings, or where GPS reception is poor. Move to an open outdoor location and wait for GPS readings to stabilize before calibrating.

Ground speed is slow to update or inaccurate

Ground speed comes from your phone’s GPS. It is affected by reception, phone placement, and background location restrictions. Readings during flight are usually more stable than those obtained while walking indoors.

The instrument does not show ground speed after connecting

• Check that the app shows Bluetooth as connected.
• Check that the app has a GPS fix.
• Check that the instrument is on a screen that supports ground speed.
• Check that split-screen mode is enabled.

13. Suggested pre-flight sequence

1. Turn on the instrument.
2. Press and hold the climb-threshold button to enable Bluetooth.
3. Open Ke_Vario.
4. Go to Settings → Connection settings (设置 → 连接设置) and connect to KEVario-BLE.
5. Wait for a GPS fix.
6. If needed, open GPS calibration (GPS校准) and calibrate altitude.
7. If you do not need ground speed during flight, turn off the instrument’s Bluetooth after calibration to save power.
8. If you need ground speed, keep the app running and prevent the system from closing it before starting your flight.

During flight, primarily use the instrument’s display and audio indications. The app can keep sending ground speed in the background while your phone is locked or stored in your backpack.