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yuri_base

Smart Altimeter

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Ever since I got an Android Wear smartwatch, LG G Watch R, which has an incredible pressure sensor with 75Hz sample rate and amazing always-on display, I wanted to have an altimeter on it with various useful features for skydive and BASE. Besides smartwatches, more new smartphones get barometric sensors. However, I haven't found any good app that would fit my needs, neither for smartwatches nor for smartphones, on any of the 3 app stores.

After I wrote L/D Vario:

[inline LDVario_v.2.0_EN.png]

- an app for thinking wingsuiters that works on 4 platforms (Android+Wear/iPhone/Windows) - I want to use my advanced data analysis algorithms and cross-platform engine for something else useful. So, here we go...

I'm going to write an app, Smart Altimeter, that will work on any device with a barometric sensor. The app will be free. (However, I don't exclude the possibility that some advanced, optional features could be purchased for a small fee - I want to eat drink beer, too, sometimes.)

The main emphasis will be made not on traditional visual use in skydiving freefall (since today's screens are still quite poor in direct sun), but on things that smart devices can give to us that "dumb" altimeters can't - taptic and audible feedback, useful features on a ride to altitude in skydiving or mountain hike in BASE, data recording and analysis, and so on.

I am all ears listening to your wishes. Let's go! :)
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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For WS I would love to have some form of data logging similar to what a flysight does with the ability to view on my smart phone immediately after the jump

Altitude/Vertical speed/horizontal speed/GR
How accurate that would be from a smart phone on my chest is debatable but it would be good enough to have a look and see if the change in body position was achieving the designed effect

Otherwise a simple data logging function like a visio/N3 offers. Exit altitude, freefall time, average vertical speeds.

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I would appreciate your input on barometer sampling rate in your device if it has one. How: download L/D Vario (free app, links above) and tap the "i" icon, you will see the info about sampling rates of accelerometer, barometer, and GPS:

[inline Frequency.png]

I'll start:

LG G Watch R: A(ccelerometer)=200Hz, B(arometer)=75Hz, G(PS)=N/A

Samsung Note 4: A=200Hz, B=5.6Hz, G=1Hz

iPhone 5: A=104Hz, B=N/A, G=1Hz

Lumia 520: A=80-90Hz, B=N/A, G=1Hz

Your turn!
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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DHemer

For WS I would love to have some form of data logging similar to what a flysight does with the ability to view on my smart phone immediately after the jump



Yes. (Though logging might be part of "Pro" feature package available as an in-app purchase.)

DHemer

it would be good enough to have a look and see if the change in body position was achieving the designed effect



For change/effect in wingsuiting, you need L/D Vario, because it measures L/D, not GR, and it's instant (~0.2s response time). It is a common misconception that observing changes in GR helps you find the sweet spot (max performance). This is because while L/D (your aerodynamic property) changes instantly with body position and AoA changes, glide ratio has an exponential response, which can take 10-20-30 seconds to stabilize and asymptotically approach sustained flight. So you need to detect a slight change in tone in 30 seconds from now - you need Mozart's ear for that. Most people using audible glide indicator mistake slow flare with improvement in L/D - they trade the forward speed to better glide ratio, which can last only limited time (although it can last up to a minute or so, depending on initial speed). When GR finally drops, they think that it's because they got tired or somehow else lost the sweet spot. Then they go do WS BASE using their muscle memory and... land in trees at linestretch trying to clear a ridge because they exhausted their forward speed without realizing it.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Funny, I was just thinking about developing my own altimeter and data acquisition platform, but for Microsoft Band 2, which was released this past Tuesday. I've been developing software for the original Band at work and got rather excited when I read that Band 2 now includes a barometer. Then I looked at the SDK documentation to find out its sampling frequency... 1 Hz [:/]

I have a Nexus 4, which has a built-in barometer, so I'm now thinking about using the Band just for display and haptic feedback. Not sure if it's worth it, though.

Google Nexus 4: A=200Hz, B=30Hz, G=1Hz

Will post the info for a Nexus 5X in a few weeks. :)

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Haha, I saw that 1Hz, too, for Band 2, was curious if I want to include it in my arsenal. Who knows, maybe internally it runs faster, just averages samples and feeds them at 1Hz only.

Don't worry about the hardware, writing code is much more important. The hardware improves so fast, that by the time you write something you find out to your delight that the hardware became much more powerful and versatile. Software is hard, because you have to do every bit of it by yourself. Hardware is easy, because you don't have to do anything.

For example, think about why LG put that 75Hz pressure sensor in their watch. They don't advertise this number, they don't even mention it in the specs. Why not 5Hz? Or 1Hz? My guess is that the manufacturers of these sensors improve their chips and retire old ones. The new ones are much better and cheap as dirt (literally - that sensor might cost just 5 cents in bulk). So an LG smartwatch designer looks at the chip catalog with thousands of different sensors and just picks something that fits their size, power, cost, etc. requirement. And it just happened to have 75Hz rate. In other words, we get better and better hardware not necessarily because market demands it, but because everything evolves and there are better components everywhere.

Code, code, code!
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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When I fly, I use my Samsung tablet for various in-flight navigation related purposes. The GPS that comes default isn't as accurate as I need it to be, especially when it comes to altitude.

I bought a Dual GPS150, which is a small box like thingy that amplifies the GPS receiving capabilities of the tablet and makes it far more reliable and precise.

I would think something like this would be beneficial in this capacity as well..

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> I bought a Dual GPS150, which is a small box like thingy that amplifies the GPS receiving capabilities of the tablet and makes it far more reliable and precise.

Yes, I have XGPS150A and 160, which I use with L/D Magic for high sampling rate (5Hz and 10Hz) necessary for Kalman Filter. For most navigation apps that do not integrate Dual's proprietary code, the update rate will be 1Hz as usual. Frankly, I gave up working with Dual and Bad Elf developer support because it sucks. But I agree that these external units are beneficial even at 1Hz since they have better GPS chips than most phones/tablets and also they drain phone/tablet's battery less as Bluetooth is far more energy efficient than GPS. A must for long hikes as you don't want a dead phone.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Lack of barometer in my device would seem to rule it out

Motorola Moto X (2014) A =100Hz, B=N/A, G=1hz

I understand the advantages of your device measuring the free airstream but a 182 is not a big plane for having something solid like that strapped on my chest

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Oooohhh, this one is even better....

I've been looking for something to replace my Suunto.

Can you make this watch so that, the watch only shows display of the altitude?

Can you zero it out to your landing area?

I don't need non of that L/D stuff....

How fast does it refresh? I need minimum once per second or at least fast as Suunto Vector does.
Bernie Sanders for President 2016

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> Can you make this watch so that, the watch only shows display of the altitude?

Of course. This will be the very first version.

> Can you zero it out to your landing area?

Absolutely.

> How fast does it refresh?

Up to 6 frames per second for textual display and 30fps for graphic display (there will be option to choose different visualizers, just like in L/D Magic). For text, anything faster than 6fps makes the last digit blink too much.

The barometer in LG G Watch R (and I presume, in Urbane) runs at 75Hz. The number crunching algorithms will run at full accelerometer speed (200Hz).

Of course, if your device doesn't have a barometer (or it's slow) and only GPS, the update rate will be limited by its sampling rate.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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stayhigh

sold.

Every half a second refreshing rate will be ideal for swooping/normal skydiving.



Note that LG G Watch R (and most likely, any other water-resistant smartwatch/smartphone) has a breathing hole with a membrane that delays changes in pressure. This effect can be easily observed just by touching the watch or pressing on its case: you see the pressure readings change and then return to equilibrium within several seconds.

Before LG, I had a Samsung Gear S which was terrible in this regard. Even on a ride up it would lag a couple hundred feet. LG is not so bad and on the ride up was pretty much in sync with my other altimeters (Altimaster and Viso). In freefall I would expect a noticeable delay in altitude. I might disassembly my watch and see if I want to puncture the membrane or drill a small hole in the case. With Gear S, I used to take the SIM door off and then the response was instant. But then the sweat could easily get inside and destroy the circuits. (Gear S instantly died when I briefly submerged it in water (with the SIM door sealed, of course) - so much for IP67 rating.)
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Anybody with any LG smartphone with a barometer? It looks like manufacturers use the same pressure sensor across their lineups: all iPhones 0.8Hz, all Samsungs 5.6Hz, all Nexuses 30Hz... I wonder if LG uses the same 75Hz pressure sensor in their phones as in their watch?
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Hi Yuri, I'm also developing a smart altimeter. I'm not sure my watch has an altimeter (Sony Smartwatch 3) - wow, I just checked, it does! Hmm, that'll teach me to check. I'm developing my altimeter app on the phone and it communicates updates to the watch for display. This has a couple of benefits in that it takes the processing load off the watch and also, the phone might be placed about one's person so it is less affected by burble. And as per your post, I wonder which has the better barometer...I'd hope the phone does! It also means one has to carry their phone with them which has pros (off landing) and cons (damage to an expensive item/ bulk of carrying it). I suspect technology will move pretty fast with this an may make my version obsolete.
Skydiving Fatalities - Cease not to learn 'til thou cease to live

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yuri_base

Craig, that's awesome! I'm curious, what's the barometer sample rate on your Sony watch? Sony Z3 Duos phone has 30Hz.



Maybe my quick Google search was wrong? It says Barometer: N/A (Accelerometer: 255 Hz)

Edit: When I googled "Smartwatch3 and altimeter" the press releases it was coming back with also included the SmartBand which does include an altimeter :-(
Skydiving Fatalities - Cease not to learn 'til thou cease to live

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yuri_base


The main emphasis will be made not on traditional visual use in skydiving freefall (since today's screens are still quite poor in direct sun), but on things that smart devices can give to us that "dumb" altimeters can't - taptic and audible feedback, useful features on a ride to altitude in skydiving or mountain hike in BASE, data recording and analysis, and so on.



I was thinking about the haptic feedback with my Smart altimeter. The vibrator(!) in the Sony SmartWatch 3 is pretty feeble and whilst I can notice it on the ground, I'm not sure I would in freefall. Not to mention the battery wear it would induce, but it's a nice idea especially for those who "flare when they hear the crickets" ;)
Skydiving Fatalities - Cease not to learn 'til thou cease to live

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yuri_base

Anybody with any LG smartphone with a barometer? It looks like manufacturers use the same pressure sensor across their lineups: all iPhones 0.8Hz, all Samsungs 5.6Hz, all Nexuses 30Hz... I wonder if LG uses the same 75Hz pressure sensor in their phones as in their watch?



LG's Nexus 5x is still 200 Hz for accelerometer, but 10 Hz for pressure and 25 Hz for temperature according to Sensor.getMinDelay(). Seems that they've gone backwards from my Nexus 4.

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yuri_base


The main emphasis will be made not on traditional visual use in skydiving freefall (since today's screens are still quite poor in direct sun), but on things that smart devices can give to us that "dumb" altimeters can't - taptic and audible feedback, useful features on a ride to altitude in skydiving or mountain hike in BASE, data recording and analysis, and so on.

I am all ears listening to your wishes. Let's go! :)



Yuri, I'm Arthur from AON2 Ltd. We think we've solved the screen problem in direct sun issue, do you want to get involved with the development of our X2 flight computer? PM me your details and we can talk :)
X2 will have GPS, 9-axis IMU and barometric pressure sensor, as well as Bluetooth Low energy to communicate with a smartphone: www.aon2.co.uk/x2

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rcdeveloper

Did anything happen with this? Was thinking of getting an LG Sport and possibly writing some app to replicate all the functionality of an LB Viso II.



Yes, I launched the basic app about two years ago, but haven't touched it since. It's on all 3 app stores. I do use it on every skydive, my favorite watch to use it with is a $50 Moto 360 Sport, since it's great in direct sun:


[inline "2017-12-01 20.23.28.jpg"]


Moto has a 25Hz barometer and is very accurate.

The next favorite is Nixon Mission with the mic lock open, this one has an insane 166Hz sample rate, but as any OLED screen is harder to see in the sun. I have LG Sport, too - but its 10Hz rate is not fast enough for skydiving.
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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I love using new tech. So I went out and bought a Moto 360 sport.
Here’s the outcome.

Downloaded “WEAR OS” app on iphone and Android.

IPHONE -
I tried it on iphone first. Setup was easy. But couldn’t find app on watch.

ANDRIOD -
I used Dad’s Android. I had to do hard reset about 4 times cause it got stuck on “getting info from watch”. It worked when I started playing with the watch, I’d actuely given up at that point.
Download the SMART ALTIMETER from google play onto the phone first or you won’t find it on the watch.

WATCH - Moto 360 Sport
Double click side button - pick play store and search for Smart Altimeter. Install.

It’s now working. Yay! Next review - after jumping crossing fingers.

A5607494-ACD1-4BE0-A4D5-E06BA7E8130E.jpeg

AD1374F8-F05A-4089-9E5E-11F6791A6913.jpeg

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