Landing deceleration - help me with product design
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Air Pressure sensor
Yes, an air pressure sensor's the way to do it at low cost and with reasonable reliability. You won't be able to guarantee that it turns off as the a/c leaves the tarmac, though (could be some minutes delay) or when it lands (all sorts of reasons why there might not be significant pressure changes at that point). You'll need to detect the descent from cruise and assume that the plane has landed (say) an hour after that.
Obviously, GPS won't work for anything inside the cabin. Accelerometers could be used to assist the pressure sensor to give a better estimate of the current status (air or ground). But it would get reasonably complicated quite quickly if you wanted to be sure of turning your device on/off within seconds of takeoff/landing.
The accelerations during takeoff and landing are extremely variable, and it would be very difficult to design something based only on an accelerometer.
Turning things on (ie after landing?) is usually less of an issue than remembering to turn them off, isn't it? I mean, the user can turn it on, if he's using the device.
Takeoff will generally be easier to detect reliably than landing (always get a gain in altitude of several hundred feet, which the very cheap barometers in e.g. Polar heart rate monitors will detect very repeatably).
Obviously, GPS won't work for anything inside the cabin. Accelerometers could be used to assist the pressure sensor to give a better estimate of the current status (air or ground). But it would get reasonably complicated quite quickly if you wanted to be sure of turning your device on/off within seconds of takeoff/landing.
The accelerations during takeoff and landing are extremely variable, and it would be very difficult to design something based only on an accelerometer.
Turning things on (ie after landing?) is usually less of an issue than remembering to turn them off, isn't it? I mean, the user can turn it on, if he's using the device.
Takeoff will generally be easier to detect reliably than landing (always get a gain in altitude of several hundred feet, which the very cheap barometers in e.g. Polar heart rate monitors will detect very repeatably).
Join Date: Mar 2008
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pressure?
Am I being silly here? What is the air pressure inside the cabin of a typical pressurised passenger transport flying at a Pressure Altitude of 35,000ft.
Please select your answer from the options below:
a) It's 35000ft you plonker, you just said so!
b) Oh no it isn't because you don't know barometric altitude!
c) Are we talking Airbus or Boeing here because it all depends!
d) Would it be about 5000ft perhaps? I mean roughly.
e) This could never happen in a TriStar
f) This could never happen in a B777
g) Couldn't happen in an Airbus they can't accelerate, far less climb.
h) Can't happen in a B787, they can't even take-off.
i) It all depends on Mach No because it just does.
j) None of the above.
I think you want something that detects an acceleration of about 7 ft/sec/sec for about 45 secs then the rumble stops; the pressure moves towards about 5000ft then stabilises provided they've remembered to click a few switches up front; it can detect a few "ding-dong" chimes inside the next 20 mins; then detect the sound of 150 seat belts unclicking etc. And then it turns the phone off.
Sorry. I must be missing something vital here. Acceleration, pressure, flying. Oh no...., it's a wind up. Well done!
Please select your answer from the options below:
a) It's 35000ft you plonker, you just said so!
b) Oh no it isn't because you don't know barometric altitude!
c) Are we talking Airbus or Boeing here because it all depends!
d) Would it be about 5000ft perhaps? I mean roughly.
e) This could never happen in a TriStar
f) This could never happen in a B777
g) Couldn't happen in an Airbus they can't accelerate, far less climb.
h) Can't happen in a B787, they can't even take-off.
i) It all depends on Mach No because it just does.
j) None of the above.
I think you want something that detects an acceleration of about 7 ft/sec/sec for about 45 secs then the rumble stops; the pressure moves towards about 5000ft then stabilises provided they've remembered to click a few switches up front; it can detect a few "ding-dong" chimes inside the next 20 mins; then detect the sound of 150 seat belts unclicking etc. And then it turns the phone off.
Sorry. I must be missing something vital here. Acceleration, pressure, flying. Oh no...., it's a wind up. Well done!
mathy,
The typical cabin altitude of a jet in cruise is 8000', not 5000'.
This and other things in your post indicate you don't know what you're talking about, so perhaps accusing others of a wind-up might be a case of fighting above your weight....
Not under everyones Regs. Under ours it's push-back till the on board system is switched on, then TOD till touch-down. Not everyone has the same rules.
The typical cabin altitude of a jet in cruise is 8000', not 5000'.
This and other things in your post indicate you don't know what you're talking about, so perhaps accusing others of a wind-up might be a case of fighting above your weight....
Furthermore, mobile phones shall be switched off/in flight mode from the time the doors are closed to the time they are open. Ie sensing the takeoff roll might be a tad late...
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The typical cabin altitude of a jet in cruise is 8000', not 5000'.
Having all electronic devices switched off for takeoff and landing kind of limits the design/creation of a product designed to continuously monitor the environment and automatically switch off another electronic device.
Having a device to switch off a mobile phone in a Porsche travelling at 155mph down an autobahn wouldn't be a bad thing, either
Rgds.
NSEU
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Useless piece of equipment if you ask me.
And btw the phone needs to be OFF for takeoff and landing, and maybe used in flightsafe mode in other flightphases!
So how is your device going to get powered if it needs to be OFF.
Some airlines have modified their aircraft so phones can be used, in that case there is no need to use flightsafe mode.
Hope your device won't make a ticking sound!!!!
And btw the phone needs to be OFF for takeoff and landing, and maybe used in flightsafe mode in other flightphases!
So how is your device going to get powered if it needs to be OFF.
Some airlines have modified their aircraft so phones can be used, in that case there is no need to use flightsafe mode.
Hope your device won't make a ticking sound!!!!
