Hi there
I'd like to present my project FlightZoomer, which offers telemetry over cellular IP at small cost:
- Onboard device: a smartphone (cost: less than for a dronecell unit)
- Ground device: a second smartphone
- Crack the NAT/firewall barrier: simply by using a relay server (which adds features b.t.w.)
- Reach the relay server via http://freedns.afraid.org/
- UDP based
- UDP hole punching trials did not bear fruit
- The communication is error tolerant in any aspects
- There is throuput throttleing as well as recovery from any failure. If e.g. the communication fails for more than 5 seconds, all the software communication layers are completely reinitialized from scratch
- While there is a mode which guarantees message delivery, most traffic works with a second fire&forget mode
- Communication using a proprietory, tailor made protocol
- The onboard smartphone talks with an APM/PixHawk using a bluetooth connection via a HC-06 device (+MAVLink)
What shall I say?
It works, latency is less than 100ms, the focus already has moved to additional features, which easily can be added on a smartphone based platform (use the rest of the available sensors/periphery like GPS, cameras, WiFi..., synthetic voice output, touchscreen)...
Impressions&look&feel of the system:
More details:
Replies
SMS is supported by GSM, 2G, 3G, 4G
SMS generated on-the-fly to send dynamic IP assigned is my novelty,
removing the necessity to use dynamicDNS server or relay server, as in your case
since smartphones can simply shake hands, exchanging assigned IP addresses
(one-time procedure)
No lattency since hands shaking performed once before the flight.
3G Video is just an example since smartphone can support 2 data channels to work
in parallel ( one for voice, one for video 3G).
If 3G video is not supported, no coverage, EDGE works fine as in your case.
Relay server, Dynamic DNS server either generate latency (ping tests)
Removing 2 middle-men reduces latency.
you said:
"
while I doubt, that any SMS based approach would offer a satisfying latency/refresh rate."
nope, SMS message is generated once only, to send the dynamic IP assigned to No.1 smartphone to secondary smartphone and vice versa.
One-time SMS communication.
Nowadays GSM, 2G, 3G, 4G service is pocket money expense, charged monthly at fixed rate, no limit on data transfer or total duration of voice calls.
Ok, thanks Darius, I understand now better.
That should work, if you can use SMS with your app.
However peer-to-peer is still a shacky thing in cell networks. I have experimented quite a bit with it, but no sucess. Getting the public IP address of each device actually was the smallest problem. The problem that my connection should occupy ports in the public firewalls and use them from then on never worked out for me.
This thread highlights some of the troubles:
http://stackoverflow.com/questions/12359502/udp-hole-punching-not-g...
I agree - dynamic DNS is not the challenge.
The problem is the data transmission between two mobile devices without a relay server. It heavily depends on the NAT/Firewall used by the mobile ISP. Afaik, it is almost impossible to communicate directly if both mobile devices are behind a symmetric NAT.
Search for "Carrier Grade NAT", "Large Scale NAT" and "Symmetric NAT".
@Darius:
If you have a working mobile peer-to-peer solution, than please share your knowledge...
All the links on your website http://flightzoomer.com/ doesn't work.
Strange, I remember getting this feedback earlier but for me all of them work....
E.g. this one covers everything regarding documentation and works for me:
http://flightzoomer.com/downloads/FlightZoomer%20Manual.1.5.1.pdf
Pls remove this solution and suggestion from your manual
since back cover can be easily detached from a smartphone undergoing shock, vibrations, ground impact, destroying valuable smartphone.
If the smartphone/back cover is detached in the thin air either smartphone or drone can be lost damaged.
BTW
excellent manual but 5-page long lighter version is welcome
6.3.1.1 Best practices The following images show some solutions how smartphones have been successfully attached to multicopters. A very successful approach was to fix only the back cover of the phone, so the phone itself could easily be detached from the copter.
You are right, there might be back covers, which would become loose too easily. In my case the mounts did pass any shaking test I applied before flying!
Also good hint to have an executive summary document...
This link works... huuh, very large manual ;-)
On your website i see for example the following link which doesn't work:
flightzoomer.com/includes/..\downloads.html
Maybe this is a browser or OS dependent problem, i am using Firefox 41.0.1 under Win 7 Prof 64
I fixed the website, should be fine with Firefox now too (tested Chrome and IE only earlier)...
Now the website works with Firefox. Thanks.
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