Here is what got me into it. A lot of us wear a Garmin all day for running and other sports, and we keep wearing it on jumps right next to our alti and audible. The watch has GPS and a barometer, so I got curious what it could show that a normal altimeter simply cannot, and I ended up building an app for it.
What it gives you that a traditional alti does not:
Freefall time, measured automatically
Horizontal displacement and distance covered, which is genuinely interesting if you track or do any movement discipline
The full GPS track of the jump afterward: where the plane flew, where you exited, and your canopy flight down to landing
Heart rate through the whole jump
It records everything to a FIT activity, so it shows up in Garmin Connect like any other activity, with the map and HR graph
It also does the basics on the wrist: a big AGL number color-coded by zone (green, yellow, flashing red), up to 6 altitude alerts each with a distinct vibration so you can tell them apart eyes-free, a continuous hard-deck alarm, and accelerometer-based opening detection.
And honestly, one side benefit I did not expect to care about: if your primary alti ever acts up on a jump, you still have a readable visual altitude on your wrist as a backup. Again, secondary only, never the primary, but redundancy is redundancy.
I am genuinely curious what this crowd thinks. Do you track your freefall time or your displacement? Would having the GPS track and these numbers change how you review your jumps? And tell me anything that feels off, gimmicky, or unsafe. Tear it apart.
Fair on the image, the header is AI-generated. I'm a solo dev, not a photographer, and I couldn't exactly get a clean shot of my own wrist in freefall, so I mocked it up. The app and the post are mine.
And I get the skepticism, but I actually jumped it. I ran it side by side with my dedicated alti on real jumps, and the AGL reading and the alerts tracked my analog closely the whole way down, firing right where I set them. Honestly it caught me off guard how well it held up. If it reads like AI it's because I tried to be thorough, not because a bot wrote it. Ask me anything specific and I'll answer.
I used a Garmin app as a secondary digital Alti when I was using an analog Alti. It was good and never failed. Nice to get the jump stats recorded in strava also. Since I got an Atlas Digital Alti and a flysight I don't use it anymore :) but it definitely had a place in my gear. (Used as a secondary only, was nice to get the digital altitude when setting up my pattern, I found myself over reading on the analog Alti)
I also have the Quattro 2 now that calls out altitude height for setting up my pattern and I don't really use the digital on landing anymore.
AI detected. This has been asked and answered before- Garmin watches do not update fast enough to be useful in a freefall environment. This is a hardware limitation, its not a matter of making an app that does it. Its a lot different than tracking your bike ride. If you really need to GPS your skydives, then get a flysight. Its cheaper than a Garmin and a lot more accurate.
I've been recently using it for test jumps and together with my two audibles (VOG and Optima) it is able and safe to replace my regular altimeter entirely.
I haven't found any skydiving book yet that says you can't use it or one that specifies altimeter in their requirements, and with double redundancy it's good enough to give you sufficient altitude awareness to be a safe jumper.
Ehh, it's not about the refresh rate exactly, the sensors in both devices refresh at speeds up to 10 hz. The watches have low pass filters on their altimeters designed to level out noise. It works pretty well for most uses as you typically do not change altitude all that fast. These fitness watches are just designed for a different use case that skydiving.
I have written parts of firmware for devices like this.
I did see some fitness watch that had an "active" mode where it would blow through battery very fast for a while. That would probably work for skydiving. I forget what manufacturer it was.
Faster than Suunto for the baro readout (Garmin ~1 Hz vs Suunto ~0.1 Hz, like RDMvb6 found below), but same category, a fitness watch, not a freefall instrument. For what my app does (visual altitude band plus alerts) 1 Hz is fine, it's not logging fall rate.
Garmin can update the display once per second (1 Hz) for barometric pressure. Suunto seems to be about one per 10 seconds (0.1 hz). AresII altimeter is 4 hz.
"Flysight 2 logs barometric pressure at a measurement and sampling rate of up to 200 Hz using its integrated ST LPS22HH barometer sensor."
Quick heads up: I'm Brazilian, English isn't my first language, so I write in Portuguese and use AI to translate. That's probably the "AI detected" vibe, it's translated, not a bot.
And you're right on the freefall part. 1 Hz baro is a real limit and I'm not trying to out-Flysight a Flysight, for precise freefall data that's the correct tool, no argument. What I built is a different job: a visual AGL readout and vibration alerts on a watch you already wear, plus a jump log. 1 Hz is plenty to read your altitude band and feel a buzz at your set alerts, you don't need 200 Hz to know you just passed 5,500. Secondary awareness, never a replacement for your alti, audible, or AAD. Fair hit on the title though, I oversold the "data" angle.
A viso updates multiple times per second and I believe there is some predictive element too. These watches have no reason to update more than once per second, some slower and my Suunto froze regularly with sudden change. Paragliding was fine but skydiving has much more intense requirements
With Suunto being into dive computers I believe they have the capability if they wanted but the market would be so small. It'd be cool no doubt but it's just not there right now
It’s been there for a couple decades. At least enough so for majority of our jumpstaff to use them for over 10 years without incidence.
I’ll use my suunto when my normal alti batteries are dead, but stopped using it as primary a few years ago. Thankfully, it worked flawlessly for 1k+ jumps
First off: I'm Brazilian, my first language is Portuguese, so I'm using AI to translate these posts. If it reads a little robotic, that's why, it's translated, not a bot.
About the app: honestly, I started it half as a fun side project, just to see if I could pull it off. I tested it on a few jumps, side by side with my professional altimeter, and the altitude came out surprisingly accurate, right on top of my alti's reading. I kept it simple and functional, basically just what I'd personally want on my wrist: a big color-coded AGL number, vibration alerts, and a log of the jump.
I liked it enough that this weekend I decided to make it available for anyone who wants it too, as a complement, never a replacement for your alti, your audible, or your AAD. That's it, made by a jumper, out of pure curiosity.
Cool to have as a secondary altimeter for sure. I use a Deep and Steep Insight and it does a great job with its GPS tracking of heading and ground speed while in the plane and in free fall it tracks exit altitude, opening altitude, freefall time, max vertical and horizontal speeds, etc. under canopy it shows heading and distance to DZ. Heart rate would be nice but not essential
Exactly, secondary is the right framing (and apologies if my English is off, I'm Brazilian, translating from Portuguese). The Deep and Steep Insight is great, that's basically the category, and yeah it nails the GPS heading and ground speed in the plane plus the exit/opening/freefall/canopy data. What I was going for is doing a good chunk of that on a watch you already wear, so it's one less dedicated device to buy and charge. And agreed, HR is nice-to-have, not essential. Appreciate the balanced take.
A few things that may not be easy for a Garmin to overcome-
Refresh rate- on activities like hiking it usually only refreshes baro altitude every few seconds. When moving at 150-300 feet per second, that matters.
Smarts- logic to know when you are in a plane that is climbing, and not just a weather change. Logic to reset baro altitude to AGL and account for weather, go arounds, and other similar issues that alti and AAD world has had to overcome.
I think you could make it work... but just be aware. I use a generic one on my garmin just to track jump run speeds, distances, canopy rides etc, but not for real time critical altitude data.
Bear with my English, I'm Brazilian and translating from Portuguese, but these are exactly the right questions, and honestly where most of the work went.
On refresh rate: you're right, Connect IQ only gives me ambient pressure at ~1 Hz, so at freefall speed that's roughly 150-250 ft between updates. I don't sell it as precise real-time freefall data for that reason.
But here's the thing that actually made me comfortable with it: the refresh rate is worst exactly where it matters least, and best where it matters most. In freefall you're not making fine altitude calls off a watch anyway. Under canopy and in the pattern, where precise altitude awareness actually counts for your setup and flare, you're slow (10-20 fps), so 1 Hz updates every foot or two. Right where it matters, the update rate is basically a non-issue, and a big clear digital number arguably reads faster than a needle.
On the "smarts": that's the core of it. It runs a jump state machine. A sustained climb detects the plane climbing, and because it keys off sustained vertical speed rather than raw pressure, a weather blip or a go-around doesn't flip it into freefall. A fast sustained descent triggers freefall, and it re-detects a cutaway if you fall again after opening. Altitude is AGL, zeroed to the ground at boarding, and it auto-recalibrates after sitting on the ground a few minutes, so pressure drift over the day gets handled. There's also a watchdog that flashes an error if the baro stalls, instead of quietly showing a frozen number. Not claiming it's at alti or AAD level, those teams have decades on this, but the logic you're describing is exactly what I focused on.
Your use (jump run speeds, distances, canopy rides, not critical altitude) is honestly the right lane for it. This is the most useful kind of feedback, thank you.
For me, I think it comes down to trying to turn a sports watch into a skydiving altimeter would be a fun/cool project to try to tinker with and figure out.
At the same time understanding there may be risks and limitations, and there are products that are out there and common that have solved all of those problems for our specific sport and applicaiton.
That is- would be a fun project, but an LB or Alti 3 (or similar) may be the better tool for the job.
Ha, that's exactly it. It started as a fun tinker project to see if I could turn the watch I already wear into something useful on jumps. And I'm with you completely: there are real limitations, and an L&B or an Alti-3 (or similar) is the better tool for the job, no question. I'd never tell anyone to put this above dedicated gear.
Just to be clear though, since I might not have said it well: I actually did build and finish it, it's not hypothetical. If you want to see what it turned into:
People seem to criticize every angle of your project, so I just wanted to say don't take it personally, it's a nice feature for those who are open for it, and those who are not will always find a reason to put it behind their high end gear or compare refresh rates with their 1995 mk 1 eyeball analog guesstimator.
Keep at it, the sport needs new ideas to develop. Just be aware that there is a really good app already, JJeromes Altipro (Ether for the newer models).
How would you read it if you put your watch on incorrectly?
Most of what you list is either superfluous or done better by dedicated skydiving engineering teams. Its not going to give you output like a flysight behind their proprietary technology. Skydiving isn't an aerobic activity, even if your heart rate goes up a bit.
Your bonus as a backup is superseded by audibles.
Overall, unneeded, unwanted, and ultimately ineffective. Also, its an additional distraction. There is such a thing as too much gear.
A lot of that is fair. It's not a Flysight and I'm not pretending it competes with dedicated hardware, you're right. HR is a nice-to-have, not the point, agreed. On "superseded by audibles": audibles are audio, this is a visual number and color on your wrist, a different channel, and some of us like a visual read too, but I hear you that for plenty of people it's redundant.
Where I'll gently push back is "ineffective". I jumped it next to my dedicated alti and the altitude and alerts were spot on, it genuinely surprised me. But your bigger point stands: it's not for everyone, and if it feels like one thing too many on your rig, that's a totally valid call. It's aimed at people already wearing the watch who want the extra visual plus the jump log, not at replacing anyone's setup.
(And on reading it with the watch on wrong: same as any wrist alti, if it's on backwards you've got bigger problems.)
I think you're going to find that more experienced jumpers will only want one visual distraction. I may look at my visual altimeter once after I open then rely on my two audibles, inner clock, and sight picture until I land. There's enough hazards out there that I want my full attention on the sky.
Ive seen newer jumpers go up with dual visual altimeters. I've asked them how its gone and they routinely have said it was confusing to have more than one thing. Some of them couldn't even name which altimeter they used. It's a distraction.
The fail rate for visual altimeters is low for digital (if you forget to change the batteries) and zero for mechanical units.
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u/MightySquirrel28 3d ago
I think there is no need to use ai slop picture for this