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# Emergency Phone Range Extender 3

 (+8) [vote for, against]

This is a last-ditch means of attempting to get an emergency signal out if you're lost somewhere with no service. You open the app, then chuck your phone as high as you can into the air. The onboard accelerometer detects when it changes direction at the apogee, where it is most likely to acquire a signal connection, and triggers the send message command, firing an SMS to emergency services with your GPS coordinates and a brief description of your emergency circumstances.

Inspired by a tech fail video I watched the other day, wherein the reviewer mentioned an app called Send Me to Heaven, which encouraged users to throw their phone up and it recorded the maximum height for scoring.

 — 21 Quest, Aug 11 2023

https://en.wikipedi...i/Send_Me_To_Heaven [pocmloc, Aug 11 2023]

Or you could use this https://www.android...nnectivity-3295162/
[a1, Aug 11 2023]

For the masses https://www.switchb...atellite-messengers
“Buy something” - as if your life depends on it. [a1, Aug 12 2023]

Coming soon to Android https://www.theverg...rvices-garmin-rumor
[a1, Aug 28 2023]

 How does the accelerometer detect the change of direction, since the phone will be almost* in freefall from the moment it leaves your hand until the moment it hits the ground?

*air resistance
 — pocmloc, Aug 11 2023

I don't know HOW it works, but that app I mentioned somehow measured the height of a throw using the accelerometer. If it knows the maximum height it's reached, then it knows when it starts going lower, and thus the optimal time to send the signal.
 — 21 Quest, Aug 11 2023

 Reading the Wikipedia article, it seems that Send Me To Heaven calculates the height by timing the duration in freefall. That is it can only calculate the maximum height after it has returned to the ground.

But it is also claimed that it checks whether the device spent more time falling than rising, but it is not clear how (or indeed if) it does this.
 — pocmloc, Aug 11 2023

Alternatively, it could probably work using the barometric altimeter found in many smartphones/watches.
 — 21 Quest, Aug 11 2023

You might have better luck promoting this as a game. As many current cellphones offer emergency messaging vis satellite, you're version would be a tough sell.
 — a1, Aug 11 2023

 It's ALREADY a game. I'm not sure that very many phones DO offer that satellite messaging. According to your linked article "to gain access to this feature, you need to have the iPhone 14, iPhone 14 Plus, iPhone 14 Pro, or the iPhone 14 Pro Max. The feature does not work on older iPhones due to the lack of specialized antennas for satellite communication. So don’t expect the feature to arrive on older iPhones at all."

 T-Mobile is the only US carrier promising a network-based alternative for such communication, through partnership with Starlink specifically, and they have less than 25% of US market share. The article doesn't even make it clear if they've even rolled out the feature yet at all, let alone which devices its available on.

It's going to be YEARS before that kind of emergency communication becomes widely available to the masses.
 — 21 Quest, Aug 11 2023

Use the accelerometer to determine time in free fall and divide by two. It's that simple. Not completely precise but it's close enough. Of course it needs the phone to survive the first throw. You could use the camera to measure airspeed based on the size of terrain features to do it in 1. Or how about using the radio to try and get an echo off the ground?
 — Voice, Aug 11 2023

 // It's going to be YEARS before that kind of emergency communication becomes widely available to the masses //

What do you think “the masses” can afford and what market penetration would you consider “widely adopted?” Widely AVAILABLE it already is, right now, to anyone who has or is willing to buy one of those phones.
 — a1, Aug 12 2023

To anyone willing to drop either \$1000 on a new iPhone or switch their service to shitty T-Mobile, vs what I'm proposing, which is a simple app that has already been PROVEN to work? The app has MUCH more reach. You're guilty of some classic Apple snobbery I'm afraid, sir. That you think anyone who might worry about needing an emergency messaging service while on a hike should be willing or able to afford to switch device OS's and/or carriers. "Can't afford an iPhone and don't want to switch to T-Mobile? Fuck you, you don't deserve to get rescued."
 — 21 Quest, Aug 12 2023

You do realize that this idea begs for a portable cell phone trebuchet with a parachute phone case attachment?...
 — 2 fries shy of a happy meal, Aug 12 2023

 Now [2fries] that is starting to look sensible. You don't need a trebuchet, a slingshot thing would work fine. The parachute could be held shut by airflow as the device ascends, and pop open as airspeed reduced to below a safe minimum. The whole kit could be packaged in an oversized (cushioned / heavy duty protective) phone case.

 In fact even better would be a phone kite, because you could reel the phone back in after use, much higher altitudes are theoretically attainable, and if it did crash the frame of the kite would act as a shock absorber.

How high do you have to go before line-of-sight becomes greater than the time-lag distance limit of cellular communication?
 — pocmloc, Aug 12 2023

 // \$1000 for an iphone //

 Huh? The iPhone 14 retails for \$799. 10% off for active duty military and veterans ;) so you personally could buy one for \$719.10 - not even counting sales, credit card points, trade in discounts, or cellphone plan rebates. Wait until the 15 comes out next month and the 14 will drop in price a bit more.

 Samsung should have satcom soon too. They announced it a while ago and I was surprised it wasn’t in latest models. WON’T be surprised if it eventually shows up but limited to premium models close to Apple’s pricing.

 if you don’t insist on having it in your cellphone though, you could get a true satellite phone (like the Inmarsat IsatPhone 2, \$519) or a GPS with emergency satellite communications (like the Garmin inReach series, starting at \$349).

Is \$349 affordable for the masses?
 — a1, Aug 12 2023

Why do you keep trying to push "buy something" so hard on an idea for an app? You're basically saying "why download an app when you could spend money or switch carriers instead?" That's retarded.
 — 21 Quest, Aug 12 2023

 I’m not “pushing” anything. I’m primarily refuting your suggestion that emergency satellite communications aren’t available to “the masses” and won’t be for years. Secondarily, your suggestion that the current entry level is a \$1000 iPhone.

 The capability had been available for years, not just from Apple, and for far less than \$1000.

Tell me what “available to the masses” really means to you.
 — a1, Aug 12 2023

 Not tied to one* manufacturer or carrier. That's what it means. It means available on all or most devices people in all tax brackets have, regardless of carrier. It means a simple fucking download, why's that so hard for you to accept?

 *Or very few.

By the way, \$719 is not what MOST folks would consider "far less than \$1000.00." You do know there are a LOT of folks using phones that cost less than \$300, right? That's an entire sector of the economy Apple just plain does not care to cater to. For instance, Xfinity Mobile is giving out the Samsung Galaxy A14 (a \$100-\$200 phone depending where you find it) with a line of service. That's what "the masses" are using. Cheapies.
 — 21 Quest, Aug 12 2023

 // Not tied to one* manufacturer or carrier //

 I’ve provided links to several options, multiple manufacturers and service providers.

 // a LOT of folks are using phones that cost less than \$300 //

 Yes, and there are emergency satcom devices available for even less than that. For the masses (link) there are some in the \$200 range - and if your life ever depended on it that could be money well spent.

 // (for the masses) means a simple download, why's that so hard for you to accept //

If your app concept (throw it up in air and pray) was slightly less silly, I’d evaluate it. Acceptance would need it to be a LOT less silly. As it stands, it’s only fun to point out just how silly it is.
 — a1, Aug 12 2023

This is the 'Bakery, mate! Silly is kinda what we do here. Saying people should HAVE to buy a dedicated device that you might not ever need and thus are likely not to have charged or on your person when you actually need it isn't silly, that's just stupid and borderline classist. Very on-brand for Apple though.
 — 21 Quest, Aug 12 2023

 OK lets cut through all this crap.

 The proposed idea was that a phone with no signal may get enough of a signal to squauk an emergency SOS with location, when it is at the top of a free flight through being thrown as high as possible.

 The proposal was for an app to monitor something to detect the maximum elevation and squauk at that time and no other time.

 However, is there a reason for the phone to stay silent on the way up and on the way back down?

 The app could just enter "repetitive squauk mode" and send its emergency broadcast repetitively at maximum power for the duration of its free flight.

Would need a dedicated app to handle the repetitive squawk mode but would not need any additional hardware, not string, not parachute, not a five meeelion squid super whizz upgrade to the latest fashion victim machine.
 — pocmloc, Aug 12 2023

That's a great idea, I'm just not sure how quickly a phone can repeatedly squawk in a few seconds of flight.
 — 21 Quest, Aug 12 2023

 I know it’s the bakery, but I think this idea falls flat. Even impossible ideas should be impossible in interesting ways.

Why does mentioning Apple upset you so, even when I just mentioned it as one in a diverse list of vendors and product offerings?
 — a1, Aug 12 2023

 //this idea falls flat// Well obviously, unless you manage to catch it.

One of the squawks will be at or near apogee
 — pocmloc, Aug 12 2023

 // how quickly a phone can repeatedly squawk in a few seconds of flight //

Depends on the compositor of the squawk. Perhaps there could be a standardized format, internationally recognized distress signal - that could be compressed and repeatable several times per second.
 — a1, Aug 12 2023

Compositor of the Squawk sounds like an awesome band name.
 — 21 Quest, Aug 12 2023

… meant to type composition, but that works too. a demon in my touchscreen corrupts my words, sometimes to good effect.
 — a1, Aug 12 2023

 Well, because it's a more interesting problem, I'm going to assume there is some benefit to timing the transmission. Maybe there need to be a connection handshake before the text is sent? Is there a limit on how often the request to connect can be sent to avoid resending while a reply is on the way?

One way to figure out the height on the way up, is to use the accelerometer while the phone is being thrown. That can theoretically give the initial speed and direction. Calculate the vertical component of that velocity, and divide by 9.8 m/s^2 to find out how long until the phone reaches max height. If it continues monitoring, it can account for collisions with leaves or possibly even account for deceleration due to air resistance, though I doubt it would be accurate enough to matter. Note that unless you can accelerate it in a straight line, you'll also need to use the gyroscope. Since gyros are often not available on low cost phones, you'll want to develop a good throwing technique that doesn't confuse the accelerometer. Perhaps watch some videos of people playing "Send Me To Heaven".
 — scad mientist, Aug 13 2023

 // (S.M.T.H.)…can only calculate the maximum height after it has returned to the ground … But it is also claimed that it checks whether the device spent more time falling than rising, but it is not clear how (or indeed if) it does //

The developer could be lying. Or they may be accounting for how big a jolt the initial throw was. By itself that wouldn’t be enough to get an altitude reading, but may apply in error checking: “No way that weak throw gave two minutes of flight time.”
 — a1, Aug 13 2023

 // this idea begs for a portable cell phone trebuchet //

Some people use slingshots to get higher S.M.T.H. scores.
 — a1, Aug 13 2023

It could be as simple as an app requiring User Input. Activate the app, a countdown as timer appears on the screen 3 - 2 - 1 TOSS!
 — AusCan531, Aug 14 2023

Modified potato cannon?
 — 21 Quest, Aug 14 2023

It depends on how quickly you want to flatten the phone's battery. In burst mode it could send out 100 signals in the time it took to decide to come back to earth. But just once. Using the GPS on my phone for altitude, which is extremely accurate if it acquires 3 or more sats, it's not a problem to tell what the apex is and get something out. I would think it's better to conserve battery life since GPS uses a ton. Sling that sucker, but be sure to get the optional CellChute soft landing system so you don't break your phone.

hmmm, instead of chucking the phone itself could you not attach a conductive filament spool to an antenna port on the phone and then launch that spool with a small model rocket or bow and arrow to get a signal.
 — 2 fries shy of a happy meal, Aug 15 2023

Those are fine ideas, IF you have such apparatus on hand when you need to send an emergency SMS. The idea behind the app as is is that it's handy as long as you have your phone.
 — 21 Quest, Aug 15 2023

And if you have already installed the app
 — pocmloc, Aug 15 2023

Well yes. Yes, that would certainly help.
 — 21 Quest, Aug 15 2023

Or, if you have an Android phone and you have AIDE (Android IDE) installed, then you can write the app yourself on your phone while taking a break sitting on a log when you decide that you need it. (Assuming you don't need to browse the web to look up any API definitions or anything, or you're not worried about using up your battery while coding).
 — scad mientist, Aug 15 2023

Tru dat ^ iPhone users better hope Apple doesn't ban this one like they banned S.M.T.H. lol
 — 21 Quest, Aug 15 2023

Suppose you have a stock phone, you go to a place where you have no signal but there is a signal 10 m up, you compose an emergency SMS, press send, and then throw the phone. Will it not just send anyway as soon as it is up and gets a signal? Is the specialist app redundant?
 — pocmloc, Aug 15 2023

I don't know, Poc, but is that a chance you want to take in an emergency?
 — 21 Quest, Aug 15 2023

A small change in programming-- extending the timeout when there is no communication -- could make it so.
 — Voice, Aug 16 2023

What do you mean the timeout?
 — 21 Quest, Aug 28 2023

Typically when you try to send a text the phone will attempt to contact the tower, timeout if unavailable, and stop after a given number of tries or a given amount of time. Simply modifying the mid level protocol to keep trying and not to stop for, say, a full minute, would allow continual retries.
 — Voice, Aug 28 2023

Hmmm.... I like it.
 — 21 Quest, Aug 28 2023

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