An acoustic variometer for your Wear OS smartwatch, with a companion phone app for settings. This manual covers both.
Overview
AIR³ Vario Watch turns a Wear OS smartwatch into an acoustic variometer. It reads the watch’s barometric pressure sensor many times per second, derives your vertical speed from it, and plays a tone whose pitch and rhythm follow that vertical speed — the sound free flight pilots use to find and centre thermals without looking at an instrument.
The app is built around two devices:
- The watch does all the work in flight: sensors, sound, GPS, automatic takeoff and landing detection. It runs on its own and does not need the phone to be nearby once it is configured.
- The phone is the settings panel. Everything you tune — thresholds, sound behaviour, units, automatic detection — is set on the phone and sent to the watch over the Wear OS connection. The subscription is also managed here.
Two features go beyond what a pressure sensor alone can do, and both are off by default: Instant Lift uses the watch’s motion sensors to signal the moment you enter lift, before any pressure change is measurable; Weak Lift gives a voice to air that is sinking less than the air around it, which is where most of a weak day’s usable lift is found. Both are described under Settings reference.
It is designed for paragliding and hang gliding, but nothing in it is specific to free flight: any activity where you want to hear whether you are going up or down works the same way.
Requirements
- A smartwatch running Wear OS 5 or later.
- A barometric pressure sensor in the watch. This is what makes a variometer responsive. Without it the app falls back to GPS altitude, which is far slower and much less precise vertically — usable to display an altitude, not really usable as a vario.
- GPS in the watch, for ground speed, heading and automatic takeoff detection. The vario itself works without GPS.
- An Android phone paired with the watch, to change settings and to subscribe.
- An active subscription to use the vario sound and the always-on display (see Subscription).
If the watch has no pressure sensor, the main screen shows a warning and the app uses GPS altitude instead. Vertical speed will be sluggish and noisy. A barometric watch is strongly recommended.
Installation
Both apps are published under a single Google Play listing, so you install them from the same place. The order does not matter.
- On your phone, open Google Play and install AIR³ Vario Watch. This installs the phone app.
- Install the watch app either by accepting the notification that appears on the watch after the phone install, or by opening the Play Store on the watch and searching for the app there.
You need both: the watch app to fly, the phone app to configure it and to subscribe.
First launch and permissions
The first time you open the app on the watch, it asks for two permissions.
| Permission | Why it is needed |
|---|---|
| Location | Ground speed, heading, GPS accuracy, automatic takeoff detection, and GPS altitude when the watch has no barometer. Required while the screen is off, which is why the app runs as a foreground service. |
| Notifications | To show the ongoing notification that keeps the app alive and lets you stop the vario without opening the app. |
You can decline both. The vario sound will still work from the barometer alone, but you lose ground speed, heading and automatic takeoff.
Once the app is open, the barometer and GPS start reading immediately — before you press anything. That is deliberate: it lets the altitude settle and the GPS get a fix while you are still packing up, so the vario is accurate the moment you start it.
The watch app
Main screen — vario stopped
This is what you see when you open the app. From top to bottom:
- GPS indicator — a coloured dot, the word GPS, and the current accuracy in metres.
- Green — accuracy 10 m or better.
- Amber — accuracy between 10 and 30 m.
- Red — accuracy worse than 30 m, or no fix at all.
If no position update arrives for 15 seconds, the app declares the signal lost: the indicator turns red, the accuracy figure disappears, and the last known speed stops being treated as trustworthy.
- Altitude and ground speed, side by side, in the units you chose on the phone.
- A warning line if the watch has no barometer.
- The Start button.
- A row of four icons.
The Start button
The button’s colour and label tell you the state of the GPS at a glance, so you know what to expect before launching:
| Appearance | Meaning |
|---|---|
| Grey — Subscribe | No active subscription. Tapping opens the subscription screen. |
| Red — No GPS | No GPS fix yet. |
| Red — Weak GPS | Fix acquired but accuracy is worse than 30 m. |
| Amber — Start Vario | Usable fix, accuracy between 10 and 30 m. |
| Green — Start Vario | Good fix, accuracy 10 m or better. |
The button always works. Even when it reads No GPS, tapping it starts the vario — the sound comes from the barometer and does not need satellites. The warning only tells you that ground speed, heading and automatic takeoff will not be available yet.
The icon row
| Icon | Action |
|---|---|
| Chart | Opens the altitude chart, where you can also adjust smoothing. |
| Speaker | Opens the sound test. |
| Phone | Opens the AIR³ app on your paired phone. |
| Exit | Tap to close the app. Long press to open the About screen. |
Flight screen — vario running
Once started, the screen switches to the in-flight layout:
- Vertical speed, large, signed, in m/s. It is green when you are climbing above the climb threshold, red when you are sinking below the sink threshold, and white in between. Both thresholds are set on the phone.
- A small green dot next to the m/s label appears when Instant Lift is running.
- Altitude and ground speed.
- Heading, as a cardinal point and a bearing in degrees (for example
NNE – 28°). It shows– –when you are too slow or stationary for a reliable heading. - The GPS indicator stays visible at the top.
- An orange Stop button.
Always-on display
When the screen dims during flight, the app stays on screen instead of dropping back to the watch face. It switches to a simplified, low-power layout showing vertical speed, altitude, ground speed and heading in plain white. Raise your wrist and the full screen comes back.
The sound continues regardless of what the screen is doing. Always-on requires an active subscription; without one, the dimmed screen simply shows a reminder to subscribe.
Stopping the vario
Press Stop. The vario plays its shutdown tone and the app immediately offers to close completely:
- Completely close — stops everything: sound, sensors, GPS, notification. This is what you want after landing; nothing keeps running in the background.
- Cancel — goes back to the main screen with sensors still running, ready to start again.
Stopping by hand also suspends automatic takeoff, so the vario cannot restart itself behind your back while you are packing up. Tapping Cancel on the close screen re-enables it.
An automatic landing stop behaves differently: the vario simply stops and the app returns to the main screen, with no close prompt.
The notification
While the app is open, an ongoing notification sits in the watch’s notification stream, with a stop action. This is what allows the app to keep reading sensors and playing sound with the screen off. It disappears when you close the app completely.
Sound test
Reachable from the speaker icon. It plays the vario tone for a vertical speed you choose by hand, from −8.0 to +8.0 m/s in steps of 0.1 m/s.
Use it to check the volume before launching, to hear what your climb and sink thresholds actually sound like, and to get familiar with the tone around zero, where the difference between a weak climb and a weak sink matters most. The sound stops as soon as you leave the screen.
Altitude chart and smoothing
Reachable from the chart icon. It draws roughly the last 15 seconds of altitude:
- Purple dots — the raw altitude derived from the pressure sensor.
- Green line — the smoothed altitude the vario actually uses.
Below the graph, Smoothing can be adjusted from 0.005 to 0.300 in steps of 0.005; the default is 0.070. Lower values give a calmer, slower vario; higher values give a faster, twitchier one that reacts sooner but also picks up more sensor noise. The value is saved on the watch.
The chart is the honest way to tune this: shake or move the watch, and watch how closely the green line tracks the purple dots.
About
Long press the exit icon. Shows the app name, the author and the installed version number. Tap Close to return.
The phone app
The phone app is one scrolling settings page. At the top, above the settings, two status lines tell you whether anything you change will actually arrive:
- Watch connection — ✓ Watch connected or ⚠ No watch connected. The refresh button re-checks.
- Subscription — active, or an invitation to subscribe with a Subscribe button.
The menu (⋮, top right) opens the About screen with the version number.
How settings are sent
There is no save button. Every change is sent to the watch the moment you make it, and the watch stores it permanently — so your settings survive closing the app, restarting the watch, and flying without the phone.
Each row confirms what happened: the value flashes green for about a second and a half when the watch accepted it, or red when it did not. Red means the setting did not reach the watch — check the connection line at the top and try again.
Settings are grouped into eight collapsible sections. Tap a section title to open it.
Settings reference
Every setting, with its default and the range you can move it in.
Takeoff
| Setting | Default | Range | What it does |
|---|---|---|---|
| Speed | 10 km/h | 1–60, step 1 | Ground speed above which a takeoff can be detected. |
| Altitude | 3 m | 0.5–20, step 0.5 | Altitude change that also counts as a takeoff, even with no GPS. Also used to confirm you really flew before any landing can be detected. |
| Window | 2.0 s | 0.5–10, step 0.5 | How long the condition must hold before takeoff is confirmed. |
| Auto takeoff | On | On / off | Master switch for automatic start. |
Landing
| Setting | Default | Range | What it does |
|---|---|---|---|
| Speed | 5 km/h | 1–30, step 1 | Ground speed you must stay below to be considered landed. |
| Altitude | 3 m | 0.5–20, step 0.5 | How much altitude may still vary and still count as stable. |
| Window | 3.0 s | 0.5–15, step 0.5 | How long both conditions must hold before landing is confirmed. |
| Auto landing | On | On / off | Master switch for automatic stop. |
Vario
| Setting | Default | Range | What it does |
|---|---|---|---|
| Climb | 0.2 m/s | 0–2.0, step 0.1 | Climb threshold. Vertical speed above this counts as climbing. |
| Sink | −3.0 m/s | −10.0–0, step 0.1 | Sink threshold. Vertical speed below this counts as significant sink. |
| Averaging | 0.20 s | 0.05–2.0, step 0.05 | Averaging window for the vertical speed. Longer is calmer and slower to react. |
| Set maximum volume | On | On / off | Forces the watch media volume to maximum when the vario starts, so you are never airborne with a vario you cannot hear. |
| Dynamic frequency | On | On / off | Lets each beep slide in pitch toward where your climb is heading. See How the vario sound works. |
| Use GPS altitude | Off | On / off | Uses GPS altitude instead of the barometer. Only useful on a watch without a pressure sensor. |
Weak Lift
An extra layer of sound for air that is better than the air around it but still going down — the mild sink that tells you a thermal is nearby. It works independently of the normal vario tone.
Worth enabling on weak days and when you are low, where the difference between working a small thermal and landing out is often air that never registers as a climb at all. On strong days it adds sound you may not want.
| Setting | Default | Range | What it does |
|---|---|---|---|
| Enable weak lift | Off | On / off | Master switch. |
| Low threshold | −0.8 m/s | −3.0–0, step 0.1 | The bottom of the weak lift band. Sink weaker than this can produce a weak lift sound. |
| Resolution | 20 cm/s | 5–100, step 5 | How fine a change in vertical speed the weak lift sound reacts to. |
| Averaging | 0.40 s | 0.10–2.0, step 0.05 | Averaging window used for weak lift, separate from the main vario averaging. |
Instant Lift
Uses the watch’s accelerometer and gyroscope rather than the barometer, to signal the moment you enter lift — the physical kick you feel entering a thermal, which arrives before any pressure change is measurable. The watch computes true vertical acceleration from both sensors, so your own turning and wing movement are not mistaken for lift.
The gain is timing: you hear the entry as it happens rather than a second or so later, which is when the decision to turn is actually made. Because it uses motion sensors, it only runs while the vario is running, and it costs extra battery. The green dot on the flight screen tells you it is active.
| Setting | Default | Range | What it does |
|---|---|---|---|
| Enable instant lift | Off | On / off | Master switch. |
| Sensitivity | 3 | 1–5 | 1 is the most conservative (fewest signals, fewest false ones); 5 is the most reactive. |
Altitude
| Setting | Default | Options | What it does |
|---|---|---|---|
| Type | QNE | QNE (1013.25) / QNH | Altitude reference. See Altitude reference and units. |
| Sea Level Pressure | 1013.25 hPa | 900–1050, step 0.25 | Only shown in QNH mode. The resulting altitude is displayed underneath in both metres and feet as you adjust it. |
| Use GPS altitude | — | Button | Only in QNH mode. Computes the sea level pressure from the watch’s current GPS altitude and pressure. Available only while the watch is sending a GPS altitude. |
Units
| Setting | Default | Options |
|---|---|---|
| Altitude | m | m, ft |
| Speed | km/h | km/h, m/s, mph, kt |
Vertical speed is always shown in m/s.
General
| Setting | Default | Range | What it does |
|---|---|---|---|
| Auto-close timeout | 10 min | 2–30, step 1 | How long the app may sit idle before closing itself. See Battery and background operation. |
| Diagnostic log | Off | On / off | Records what the watch was measuring during each flight. See Diagnostic log. |
| Open Last log | — | Button | Opens the most recent log file. |
| Delete All logs | — | Button | Deletes every log file. There is no confirmation and no undo. |
How the vario sound works
Two things change with your vertical speed: the pitch and the rhythm.
Climbing, the tone is high and broken into beeps. The stronger the climb, the higher the pitch and the shorter and closer together the beeps — so a strong thermal sounds fast and urgent, a weak one slow and lazy. Sinking, the tone drops low and stretches into a long, almost continuous growl that gets deeper the faster you go down. Between the two, around zero, the sound is quiet and unhurried.
The transition is continuous rather than stepped: the pitch and rhythm shift smoothly as your vertical speed changes, which is what lets you hear a climb strengthening or fading rather than only hearing that it exists.
Dynamic frequency
With Dynamic frequency on, each beep does not hold a single pitch: it slides toward the pitch of the vertical speed you are heading for, based on the current trend. A climb that is strengthening sounds like a rising beep, one that is fading sounds like a falling beep. It tells you where the air is going, not only where it is — useful when centring a thermal, since you hear the improvement before the average catches up. Turn it off for a plainer, more traditional tone.
Start and stop tones
The vario plays a short confirmation sound when it starts and another when it stops. With automatic takeoff enabled, this is how you know the vario has armed itself without looking at the watch.
Automatic takeoff and landing
The point of these is that you never have to remember to start or stop the vario. Both need an active subscription.
Automatic takeoff
With Auto takeoff on, the watch starts the vario by itself when either of two conditions holds for the whole takeoff window:
- By GPS speed — your ground speed stays at or above the takeoff speed. This is the normal case for a running launch.
- By altitude — your barometric altitude changes by at least the takeoff altitude value. This works without GPS and covers cases where you gain height without much ground speed.
Either one is enough on its own.
The GPS updates about once a second, so a window shorter than a couple of seconds gives the speed test very few samples to work with. Two seconds or more is a sensible floor. If your vario starts while you are walking around launch, raise the takeoff speed rather than shortening the window.
Automatic takeoff is suspended after you stop the vario by hand, and stays suspended until you tap Cancel on the close screen or reopen the app.
Automatic landing
With Auto landing on, the watch stops the vario when it is satisfied you are on the ground. The test is deliberately conservative, because a vario that stops mid-flight is worse than one that keeps beeping on the ground. Four things must all be true:
- The vario has been running for at least 5 seconds.
- You actually flew — your altitude has changed since the vario started by at least the Takeoff → Altitude value. Until that happens, no landing can be detected at all. This is what stops a ground test or a forgotten vario from “landing” on its own.
- Your altitude has been stable for the whole landing window — the total variation stays within the landing altitude tolerance.
- Your ground speed is below the landing speed throughout — counting only readings the GPS itself reports as precise.
That last point matters more than it looks. When GPS reception drops — under a wing, in a valley, in a turn — the watch reports a speed of 0 km/h simply because it has nothing better to say. Taken at face value, that looks exactly like standing still in a field. So the app tracks how confident the GPS is in each speed reading and discards the ones it cannot trust, rather than reading them as proof that you have stopped. When speed is unusable, stable altitude alone has to carry the decision — and since gaining or losing height is precisely what flying does, that remains a demanding test to pass in the air.
When all four hold, the vario stops, plays its shutdown tone, and the app returns to the main screen. The app itself stays open, and closes on its own once the auto-close timeout expires.
Altitude reference and units
A barometer measures pressure, not height. To turn pressure into altitude, the app needs to know what pressure to treat as sea level.
- QNE uses the international standard value of 1013.25 hPa. The result is a pressure altitude — the same reference everyone else in the air is using, and what you want for airspace. It is the default.
- QNH uses the actual sea level pressure of the day, which you set yourself. The result matches real height above sea level, so it agrees with the altitude marked on your map.
In QNH mode, the phone shows the resulting altitude in metres and feet as you adjust the pressure — so you can simply turn the value until the altitude matches the known elevation of your launch site. The Use GPS altitude button does the same thing automatically, computing the sea level pressure from the GPS altitude and the pressure the watch is currently reading. It works only while the watch has a GPS altitude to send.
Switching back to QNH resets the pressure to 1013.25 hPa, so you always start from a known value.
Altitude can be displayed in metres or feet, and ground speed in km/h, m/s, mph or knots. Both are set on the phone and applied on the watch immediately. Vertical speed is always in m/s.
Battery and background operation
A vario is demanding: the barometer, GPS and audio all run continuously, and the app holds the watch awake so the sound never stops when the screen dims. Expect noticeably shorter battery life than a normal day of watch use, and start a long flight on a full charge.
Two things keep this under control.
The auto-close timeout
If the app is open but the vario is not running, it closes itself completely after the timeout — 10 minutes by default, adjustable from 2 to 30 minutes on the phone. This is the safety net for the app left open in your pocket after landing.
The timer restarts on any interaction: opening a screen, pressing a button, receiving a setting from the phone. And it never runs while the vario is active — a long flight will not close the app on you.
Closing it yourself
The reliable way to stop everything is the exit icon followed by Completely close. That releases the sensors, GPS and audio and removes the notification. Simply swiping the app away leaves the service running.
Subscription
AIR³ Vario Watch is free to install and free to try. An annual subscription, purchased through Google Play, unlocks the flying features.
| Free | Requires a subscription |
|---|---|
| Altitude display Ground speed and heading GPS status and accuracy Sound test Altitude chart and smoothing All settings on the phone | The vario sound Automatic takeoff and landing Always-on display in flight |
Subscribing
Subscribe from the phone app: tap Subscribe in the banner at the top of the settings screen and complete the Google Play purchase. The subscription is tied to your Google account, so it covers both apps.
Tapping Subscribe on the watch does not open a purchase screen there — it opens the AIR³ app on your paired phone, where the purchase happens. This is a Wear OS limitation, not a step you can skip.
How the watch knows
The watch checks its own Google Play subscription status directly, and re-checks every 24 hours, so an expired or cancelled subscription is picked up without you doing anything. The phone also forwards its status to the watch, which is what makes a fresh purchase appear on the watch quickly.
If the watch has been offline for a long time, open the app while it is connected to the phone to let it re-check.
Diagnostic log
If the app does not behave the way you expect — the vario starting or stopping at the wrong moment, for instance — you can have it record a log file to help you understand what happened.
Turn it on under General → Diagnostic log on the phone. It is off by default and only records while the vario is running. Each flight is recorded as a self-contained session: the settings in force at the time, how and why the vario started, what the sensors were reading second by second, and how and why it stopped. That is usually enough to see which threshold needs adjusting rather than having to guess.
The watch sends the log to the phone during and after each flight, and the phone saves it as a plain text file in your Downloads folder, grouped by day. Open Last log opens the most recent one; if nothing on your phone can display a text file, open it from Downloads with a file manager instead. Delete All logs removes them all at once, with no confirmation and no undo.
A log holds your settings and sensor readings only — no track and no position.
Troubleshooting
The phone says “No watch connected”
Check that the watch is paired and connected in your companion app (Wear OS or Galaxy Wearable) and that Bluetooth is on. Then tap the refresh button next to the message. Settings cannot be sent while this line is red.
A setting flashes red when I change it
The setting did not reach the watch. Check the connection line at the top, then change the value again. If several settings in a row fail, restarting both apps usually clears it.
My settings did not arrive on the watch
The Wear OS link between phone and watch can take a moment, and occasionally needs a nudge. Confirm the watch is connected, then re-send the setting by changing it and changing it back. Settings already accepted are stored on the watch and are not lost.
I cannot hear the vario
- Check that the watch is not in silent or theatre mode.
- Check the watch media volume, or turn on Set maximum volume on the phone so the app raises it for you.
- If you are wearing Bluetooth headphones paired to the watch, the sound goes there instead of the speaker.
- Use the sound test to confirm audio works at all before blaming the vario.
The vario will not start
If the button reads Subscribe, there is no active subscription. Otherwise the button starts the vario in any GPS state — a red No GPS label does not block it.
The app closed by itself
That is the auto-close timeout: the app was open with the vario stopped for longer than the configured delay. Raise it under General → Auto-close timeout on the phone if you want more time.
The vario started while I was still on launch
Automatic takeoff triggered on your walking speed or on an altitude change. Raise Takeoff → Speed, raise Takeoff → Altitude, lengthen Takeoff → Window, or turn Auto takeoff off and start the vario by hand.
The vario stopped in flight
Automatic landing needs stable altitude and a trustworthy low ground speed together, so this is unlikely — losing GPS reception on its own will not do it. It can still happen in very smooth air at low ground speed, typically in a weak, flat thermal. Increase Landing → Window, decrease Landing → Speed, or turn Auto landing off. You can always restart from the main screen.
If it keeps happening, turn on the diagnostic log and fly again — the log will show the exact altitudes and speeds behind the decision, which is a far better basis for adjusting your thresholds than guesswork.
The vertical speed is jumpy, or too slow to react
Adjust Vario → Averaging on the phone, and the smoothing value on the watch’s chart screen. Longer averaging and lower smoothing give a calmer vario; the opposite gives a faster one. The chart screen lets you see the effect directly.
FAQ
Do I need my phone with me when I fly?
No. The watch app is fully standalone. Configure it once from the phone and leave the phone in the car.
Does it work without GPS?
Yes. The vario sound comes from the barometer alone. Without GPS you lose ground speed, heading and automatic takeoff by speed — but automatic takeoff by altitude still works.
Does it record my flight?
No. AIR³ Vario Watch is a variometer, not a flight recorder or navigation instrument. It does not log tracks.
Can I use it for something other than free flight?
Yes. Anything where hearing your vertical movement is useful — gliding, ballooning, or any activity where you want to track altitude changes — works the same way.
Why does it need location permission?
For ground speed, heading and automatic takeoff detection, and for altitude when the watch has no barometer. Since these must keep working with the screen off, the app runs as a foreground service with an ongoing notification.
Can I change the tones?
The tones themselves are fixed, but what you hear and when is yours to shape: climb and sink thresholds, averaging, dynamic frequency, Weak Lift and Instant Lift all change the behaviour of the sound.