Author Topic: Bringing a DIY battery powered device in flight?  (Read 12566 times)

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Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #25 on: September 19, 2017, 05:47:23 am »
Don't bother. Bring it as usual and everything will be fine. If the X-ray says something, just explain to them, and the worst being the battery pack being confiscated.
I brought 12 D cell shaped ultracaps and a bunch of industrial power supplies with me when I first came to US, and airport didn't even bother letting me know, they just quietly examined my luggage and let it go.
I also once brought a rack mount server with me on a Chinese domestic flight, the airport authority called me and checked my bag in front of me, and let it go.
I also once tried to bring some explosives (trace amount, in milligrams, diluted in baking soda, used to showcase my ion mobility spectrometer in a design contest), and unfortunately got spotted by airport IMS device, and I was brought to airport police and they asked why. After knowing I'm not trying to blow up the aircraft, they confiscated my explosive samples, but allowed me to board with my equipment. That was in 2012, where China was seeing the most threat of Xinjiang/Tibet separatism terrorism, and at that time I was living in a province very close to Xinjiang. Needless to say, airport alert couldn't be more sensitive, and yet I didn't land in jail.
The battery pack is inside, soldered and screwed shut so if they won't let the cell in the whole thing stays haha. It does only use a 2000mah cellphone battery and I have brought along much bigger ones before without issue so the cell itself should not be a problem.

If all else fails either I leave it at home or bring it and see what happens. If I get stopped I just say it is a gps logger to record my trip.
 

Offline Jeroen3

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Re: Bringing a DIY battery powered device in flight?
« Reply #26 on: September 19, 2017, 06:49:13 am »
Does you GPS even work at the altitude and speed. Wasn't there some limit imposed on those?
 

Offline janekm

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Re: Bringing a DIY battery powered device in flight?
« Reply #27 on: September 19, 2017, 07:05:44 am »
I travel fairly frequently with a bag pack full of electronic prototypes and associated component and cables, and my general experience is that X-ray operators are looking for shapes/patterns that they have been trained are suspicious (“like a blade”, “like a gun”, “like explosives”) rather than things that they are not familiar with. I do occasionally have to send my bundle of wires through a second time as it’s deemed too messy to discern. My “opening tool” (blade-shaped piece of flat steel) and tweezers do get inspected on occasion, but not confiscated.
I did once cause the airport police to get called as I and a colleague were traveling with 50 D-cell Li-FeSo2 batteries with short leads manually soldered on (spares for some animal tracker experiments).
The security person politely explained that in their training they were told that the same style of battery with improvised leads was favored as a power source by makers of bombs, and they didn’t feel comfortable letting us take them on the plane, but we could pick them up from the local police station on our return.

BTW the thing you’d want to watch out for is fertilizer, if you’ve got a speck of that on your luggage it will set off the explosives testers ;)
 

Offline tooki

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Re: Bringing a DIY battery powered device in flight?
« Reply #28 on: September 19, 2017, 10:56:50 am »
Does you GPS even work at the altitude and speed. Wasn't there some limit imposed on those?
Correct, but the limits are 1000 knots or 18000m, both far above what an airliner is capable of today. It's called the COCOM limits.
 

Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #29 on: September 19, 2017, 05:08:37 pm »
I travel fairly frequently with a bag pack full of electronic prototypes and associated component and cables, and my general experience is that X-ray operators are looking for shapes/patterns that they have been trained are suspicious (“like a blade”, “like a gun”, “like explosives”) rather than things that they are not familiar with. I do occasionally have to send my bundle of wires through a second time as it’s deemed too messy to discern. My “opening tool” (blade-shaped piece of flat steel) and tweezers do get inspected on occasion, but not confiscated.
I did once cause the airport police to get called as I and a colleague were traveling with 50 D-cell Li-FeSo2 batteries with short leads manually soldered on (spares for some animal tracker experiments).
The security person politely explained that in their training they were told that the same style of battery with improvised leads was favored as a power source by makers of bombs, and they didn’t feel comfortable letting us take them on the plane, but we could pick them up from the local police station on our return.

BTW the thing you’d want to watch out for is fertilizer, if you’ve got a speck of that on your luggage it will set off the explosives testers ;)

Reminds me of the time when we were about to go home from Thailand. metal detector kept on beeping even when I have already taken out everything metal I had on me. Realized it was a metal strip bracket (used for the back of car stereos) I picked up somewhere and put it in my back pocket. I thought they were going to confiscate it but let me through with it when they saw it wasn't anything sharp.
 

Offline SeanB

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Re: Bringing a DIY battery powered device in flight?
« Reply #30 on: September 19, 2017, 06:52:29 pm »
GPS will work in a plan4e only if you have a window seat, and place the GPS antenna right by the window to get a sky view, and have had it running ( with a decent lock) for a while before you board, so that it has a good up to date empheris of the local area before you take off, and thus can maintain lock while in flight with only the limited sky view available through the window. Will be inaccurate in height and will occasionally loce lock when no satellite is in view of the window, but will work, provided the seat you have is on the side of the plane that will mostly be facing the Equator during the flight, so the probability of having a trio or more of the GPS satellites in view all at the same time is higher.
 

Offline IanMacdonald

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Re: Bringing a DIY battery powered device in flight?
« Reply #31 on: September 19, 2017, 07:24:37 pm »
One some flights you can't take a laptop unless it can be powered on.

On offshore helicopters you couldn't take anything with batteries in it, but could take loose batteries. On one occasion my colleague had to tear-down an expensive signal strength meter. and strip out  the fixed internal batteries to get it to an offshore platform.

Now, I know that terrorists are a serious concern, but sometimes I wonder if bureaucrats are an even more direct threat to civilization.  :--
 

Offline Jeroen3

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Re: Bringing a DIY battery powered device in flight?
« Reply #32 on: September 20, 2017, 09:01:47 am »
 :-DD, tear down equipment... Engineer + Equipment, or no engineer. You'd be amazed how quickly there is an exception for Engineer + Equipment get there to fix the problem.
 

Offline Beamin

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Re: Bringing a DIY battery powered device in flight?
« Reply #33 on: September 20, 2017, 08:56:10 pm »
I was able to get a fix via mobile and it worked. The inaccuracy I mentioned was when I compared them back on the ground side by side. Speed was fine but altitude was off by a hundred feet. But when I compared my gadget vs a garmin unit, they were pretty close.

Maybe others have a better experience with a free app that they could recommend :)
What about a standalone, off-the-shelf GPS logger? Like the kind some photographers use for geotagging photos when their cameras have no internal GPS. They simply create a time-stamped log file in a user-selectable interval, saved to a common format like NMEA or GPX.

Back in the day I had Microsoft streets and trips and the antenna was a little square you suctioned cupped on the window of your car. It worked on an airplane. Was interesting to see the path of the plane on the map fly directly over the WTC in NYC. But that was before you could get stand alone GPS for your car and I rigged up a lap top in the front seat. It was very high tech at the time being able to get wifi anywhere near a router because passwords had to be manually configured and nobody did this at the time. I had so many internet point I put a password on gave myself and the owner exclusive access. They were none the wiser. 
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Offline David Hess

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Re: Bringing a DIY battery powered device in flight?
« Reply #34 on: September 21, 2017, 05:44:38 pm »
But from what I hear, standalone GPS receivers have trouble on aircraft, too, so it's probably the Faraday cage issue. (GPS signals are extremely weak.)

I have used my standalone GPS receivers several times on large passenger aircraft without problems.  They worked better with the external patch antenna held up against the window but maintained a lock without it using their internal helical antenna.
 

Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #35 on: October 18, 2017, 02:14:19 pm »
Update: passed through 2 airports without questions. Just stuck it in a pouch that also holds my usb cables and chargers.

One issue though, the first xray exposure seems to have damaged the eeprom as a few of the values stored in memory gets wiped out at power down, it worked before as i have been using it on the road so code is not at fault.

Interesting fact: i was seated beside the window on the rearmost seat of the plane. I was able to get up to 8 satellites locked but then everything disappeared at cruising speed and altitude. It came back when the plane slowed down nearing the destination. I suspect it is static electricity from the wind and exhaust swamping the gps signal. Let's see how it fares on the connecting flight. Waiting to board right now. :)
 

Offline David Hess

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Re: Bringing a DIY battery powered device in flight?
« Reply #36 on: October 18, 2017, 06:06:54 pm »
One issue though, the first xray exposure seems to have damaged the eeprom as a few of the values stored in memory gets wiped out at power down, it worked before as i have been using it on the road so code is not at fault.

It would take a huge amount of x-ray exposure to damage an EEPROM beyond just erasing it.  X-rays can actually be used to erase them just like ultraviolet except you can apply x-rays through a package.  Even erasing floating gate memory takes a much larger dose than will be found in an x-ray scanner.

Quote
Interesting fact: i was seated beside the window on the rearmost seat of the plane. I was able to get up to 8 satellites locked but then everything disappeared at cruising speed and altitude. It came back when the plane slowed down nearing the destination. I suspect it is static electricity from the wind and exhaust swamping the gps signal. Let's see how it fares on the connecting flight. Waiting to board right now. :)

That should not happen.  What GPS was this?  I think it more likely that the software has built in limitations beyond those required for civilian GPS receivers.
 

Offline ajb

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Re: Bringing a DIY battery powered device in flight?
« Reply #37 on: October 18, 2017, 06:35:03 pm »
GPS receivers that operate above 60,000 ft and 1000 nmph are controlled on the US Munitions List (because they could be used to guide missiles), so most GPS receivers will stop working above one threshold or the other*.  I'm pretty sure your commercial airliner wasn't violating either limit, but it's possible that the manufacturer was simply playing it very safe and have configured it to drop out well below the limits.  Or possibly they have higher performance and higher priced models they would prefer you buy.

* Actually the way the law is written, only devices that operate above 60000ft AND 1000nmph are controlled under the USML.  Receivers that can operate above 600m/s are classified in the US Commerce Control List, so they're still controlled, but not as severely as if they were on the USML.  Other countries probably have similar controls on GPS receivers in place, but I would be surprised if any are MORE restrictive than the US.
 

Offline Beamin

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Re: Bringing a DIY battery powered device in flight?
« Reply #38 on: October 18, 2017, 10:06:41 pm »
GPS receivers that operate above 60,000 ft and 1000 nmph are controlled on the US Munitions List (because they could be used to guide missiles), so most GPS receivers will stop working above one threshold or the other*.  I'm pretty sure your commercial airliner wasn't violating either limit, but it's possible that the manufacturer was simply playing it very safe and have configured it to drop out well below the limits.  Or possibly they have higher performance and higher priced models they would prefer you buy.

* Actually the way the law is written, only devices that operate above 60000ft AND 1000nmph are controlled under the USML.  Receivers that can operate above 600m/s are classified in the US Commerce Control List, so they're still controlled, but not as severely as if they were on the USML.  Other countries probably have similar controls on GPS receivers in place, but I would be surprised if any are MORE restrictive than the US.

GPS civilian use encoding mechanism is open to the public, so if you implement the decoder with fpga then you can bypass the usml limitation.

I thought they overcame that approach by limiting how much of the time signal a civilian GPS can decrypt. Or is that just a cut off as to how many decimal places the location can read to introducing error in precision? The GPS signal is 0.00000000000001 seconds accurate but the GPS can only decode the first 0.00000000 seconds making pin pointing a location impossible. MAybe...
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Offline Red Squirrel

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Re: Bringing a DIY battery powered device in flight?
« Reply #39 on: October 19, 2017, 01:26:21 am »
The LCD may pose a problem, because we all know real bombs have LCDs on them!  :-DD   But sadly it seems that's what they're trained to look for.  Like that kid that opened up a clock and everyone freaked out thinking it was a bomb.  I personally would not chance it myself, though I tend to be randomly selected more often than not.  Probably for being a ginger, and a quiet one at that.  We can't be trusted.  :P
 

Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #40 on: October 19, 2017, 04:46:17 am »
I think signal loss is due to environmental factors not software limitation as beyond about 500kph i started losing satellite locks and beyond 700kph i lost all lock, putting the device right at the window gave me a split second lock reading 930kph but lost it again. Also, while climbing to altitude, altitude readings were stuck to about 150+m. During approach, when the engine was throttled down, altitude started working right at below 500kph and 6000m. So I'm still thinking it had to do with the static or similar effect. Keep in mind I had gps lock before boarding the plane and then kept it near the window for updated ephemeris.

My connecting flight didn't fare any better. Forgot to turn it on and get a lock before boarding and being seated a seat between the window plus the a380 seems to have smaller windows too. So no data from that flight. Would have been fun as it was 12hrs Hong Kong to London.

Ps: I'm using a ublox module with ceramic antenna, typical arduino building blocks from china. I think if the eeprom has not been damaged, part of the code that retrieves the stored eeprom data may have been corrupted which explains some of them not working right.

Edit: the way the gadget was designed, when powered down, there is zero power on everything. uC does not go to sleep mode at power off. Maybe power may have been inadvertently applied while passing the xray machine. Not sure if it has any effect..
« Last Edit: October 19, 2017, 05:00:20 am by djQUAN »
 

Offline David Hess

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Re: Bringing a DIY battery powered device in flight?
« Reply #41 on: October 19, 2017, 12:02:45 pm »
You did not say which U-blox receiver you are using but:

https://www.u-blox.com/sites/default/files/products/documents/u-blox8-M8_ReceiverDescrProtSpec_%28UBX-13003221%29_Public.pdf

u-blox receivers support different dynamic platform models (see table below) to adjust the navigation engine to the expected application environment. These platform settings can be changed dynamically without performing a power cycle or reset. The settings improve the receiver's interpretation of the measurements and thus provide a more accurate position output. Setting the receiver to an unsuitable platform model for the given application environment is likely to result in a loss of receiver performance and position accuracy.

The "automotive" dynamic platform model has a limit of 6000 meters altitude and 360 kilometers per hour.
 

Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #42 on: October 19, 2017, 02:46:56 pm »
You did not say which U-blox receiver you are using but:

https://www.u-blox.com/sites/default/files/products/documents/u-blox8-M8_ReceiverDescrProtSpec_%28UBX-13003221%29_Public.pdf

u-blox receivers support different dynamic platform models (see table below) to adjust the navigation engine to the expected application environment. These platform settings can be changed dynamically without performing a power cycle or reset. The settings improve the receiver's interpretation of the measurements and thus provide a more accurate position output. Setting the receiver to an unsuitable platform model for the given application environment is likely to result in a loss of receiver performance and position accuracy.

The "automotive" dynamic platform model has a limit of 6000 meters altitude and 360 kilometers per hour.
I admit I didn't really check the limitations before, but pics of the modules are in the OP and it is using a ublox neo-6m-0-001 module. Quick look at the data sheet says 50000m and 500m/s unless I understood wrong :)

Edit: going to be here around UK for about 10 days, london, Edinburgh, glasgow, liverpool. Brought some pink leds and pcb modules to give to bigclive if i ever stumble upon the guy but time is limited as I'm with a big tour group and a hectic schedule. How much would shipping be? It's just a tiny box could even possibly fit an envelope. Not to mention there are a few more of our favorite youtube stars are in this area too :)
« Last Edit: October 19, 2017, 02:55:45 pm by djQUAN »
 

Offline David Hess

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Re: Bringing a DIY battery powered device in flight?
« Reply #43 on: October 19, 2017, 07:52:33 pm »
I admit I didn't really check the limitations before, but pics of the modules are in the OP and it is using a ublox neo-6m-0-001 module. Quick look at the data sheet says 50000m and 500m/s unless I understood wrong :)

I knew exactly what to look for because of how you described the failure.  As far as I can tell from their documentation, the U-blox 6m supports the same modes and it can be reprogrammed; 50,000 meters and 500 meters per second only applies when in Airborn 4g mode.

CFG 0x06 Configuration Input Messages: Set Dynamic Model, Set DOP Mask, Set Baud Rate, etc.

https://www.u-blox.com/sites/default/files/products/documents/u-blox6_ReceiverDescrProtSpec_%28GPS.G6-SW-10018%29_Public.pdf
 

Offline djQUANTopic starter

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Re: Bringing a DIY battery powered device in flight?
« Reply #44 on: October 19, 2017, 08:47:45 pm »
The pdf linked showed that the default was in portable mode which has limits more than enough for passenger planes. I admit I'm just a beginner so I may not fully understand what I'm saying ;D I just used the tinygps++ library to extract the gps data from the module, I'm not sure if it has capabilities to send commands but as far as I can tell, it doesn't. I could post the code I used but I didn't bring my laptop on this trip so those interested may have to wait until I get back. I'll do more reading about the module from the info you shared thanks.
 

Offline David Hess

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Re: Bringing a DIY battery powered device in flight?
« Reply #45 on: October 19, 2017, 09:02:12 pm »
The pdf linked showed that the default was in portable mode which has limits more than enough for passenger planes.

I assume it got reset at some point or maybe the library you are using configures it to a known state.
 

Offline Beamin

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Re: Bringing a DIY battery powered device in flight?
« Reply #46 on: October 20, 2017, 12:31:32 am »
The pdf linked showed that the default was in portable mode which has limits more than enough for passenger planes.

I assume it got reset at some point or maybe the library you are using configures it to a known state.

Are you making ICBM's? Why don't you install a gimbal system with autolocation that you calibrate on the ground. Make sure you use 4 gimbals so you don't get gimbal lock. Inertial guidance system. With GPS as a coarse error checking device. ICBMs are ballistic so the guidance and navigation are only needed the first 1/4 of the flight the rest can be done with physical altitude/ speed sensors and the gimbal system which can be bought of ebay and its all analog so easy to reimplement . Decoys and stage seperationcan be set off by simple timers. And the fuse could detonate off pulse radar in the tip. A really hard way to get a war head full of yard sale fliers out to a different country but you could get a large coverage area with you leaflet's . .
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Offline A Hellene

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Re: Bringing a DIY battery powered device in flight?
« Reply #47 on: October 20, 2017, 05:32:46 am »
Ah! The civilian GPS restrictive laws, the ridiculous draconian fines on individuals that 'might have scared other passengers' by the usage of their devices on flight, any possible GPS reception jamming or spoofing procedures during flight, as well as the frenetic TSA restrictions of custom-made devices (not approved by the authorities as 'safe' --but not safe for whom, really, if I might ask?) being powered-on during (some of the) international flights, et cetera, might actually be imposed in order to prevent flat-earth theory from leaking out... ::)

Especially after those Elon Musk's acrobatics in public... :P


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Offline tooki

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Re: Bringing a DIY battery powered device in flight?
« Reply #48 on: October 22, 2017, 01:43:59 pm »
Tin foil hat much??

The restrictions on civilian GPS are entirely reasonable, insofar as they only kick in above 60’000 feet, which no civilian aircraft reaches. The other restrictions shown in this thread are not legal ones, but technical ones, because no one GPS receiver is optimized for all usage scenarios. Consumer GPS tends to be optimized for the typical consumer GPS applications, i.e. on the ground, at well-below-subsonic speeds.

TSA restrictions on homemade gadgets: no such restriction actually exists. But since the local TSA agents have final say on what does and doesn’t board, and they mostly got their “what a bomb looks like” training from Hollywood movies, when they see wires, they freak out. But that still does not mean it’s an official restriction.
 

Offline Mjolinor

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Re: Bringing a DIY battery powered device in flight?
« Reply #49 on: October 22, 2017, 02:04:03 pm »

You have to try to educate the people at the airport. In some cases it is not possible as it is not possible to make them smile no matter how hard you try.

I had the mother of all arguments with a women at CDG who insisted I could not board a plane with my Insulin. She lost eventually due to intervention from her boss but for sure I am glad I have never had to deal with her again.

I have also carried a lot of high voltage capacitors on planes, these are about a foot long, circular and brown, oil filled paper wound things. They raise a lot of eyebrows but I have never been refused.
 


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