Model Aircraft Potential Software
 

Howdy

It has occured to me, that the N900 has several features that would be really useful in flying model planes. For example the accelerometer, camera and the GPS (altimeter and speedometer).
Writing the software for this shouldn't be too hard, and if the camera isn't used it could be text only.

The only problem I can think of this is the wireless range. What would have the best range out of the wifi or bluetooth radios? I'm thinking of having a laptop at the flying field to recieve the signal, or ssh into the phone for the text only solution.

Is it possible to get a range of a few hundred meters (through air) with any of the radios on the n900? If a text only solution is used then it would be possible to get away with a very low data transmission rate. Perhaps only a few bytes per second. although I have no idea whether this is possible with the radio stack on the n900.

Thanks.

Joe.

Re: Model Aircraft Potential Software
 

I suppose this would be for telemetrics only (and maybe a video feed) ? It's a kinda cool hack idea but the N900 is kinda heavy to be put a flyer (unless it's a rather large one) and it needs to have unobstructed view of the sky for the GPS to work optimally (CF is pretty good conductor AFAIRecall so it will probably block GPS signals).

Bluetooth will likely be a problem, wifi should not be since you have full LOS (Line Of Sight) and of course you could put a better antenna to the laptop end (actually it might be a good idea to use a base-station [with good antennas] that both the n900 and the laptop connect to rather than ad-hoc).

However the modern radios that operate on 2.4Ghz might get interference from the WiFi (also 2.4Ghz...) so even if you use old-fashioned radio (like I do) if you're on a field with other people it might not be the best of ideas...

I just put a small camera and video transmitter on my RC heli but as stated I have old 35Mhz radio so the 2.4Ghz video tx does not interfere (and I have plenty of flying space on my own "yard" [2ha] so no need to worry about other people). Unfortunately I was paying too much attention to the wrong things (like how well the video feed worked) and touched ground with the tail rotor, stripping gears from tail servo, and things went downhill from there (actually seems I only stripped gears from a cyclic servo in the resulting crash, need to dismantle the rotor head still to check if the feathering shaft got bent)

Re: model aircraft software
 

I'm sorry to hear about your crash.

Having posted a similar thread here it seems as though this probably isn't the best solution to the problem. The n900 is substantially heavier than the standalone components would be. And as I'm sure you know, keeping your eyes on the model is pretty important. Although perhaps having a "co-pilot" manning the instruments might work.
I don't think that interference should be much of a problem although it would be important to test this before take-off.

I wonder whether it would be possible to use the gprs radio though. Directly to the laptop, the latency from the cell network would be too great to be useful.

Having the fpv goggles and a hud would be very cool indeed.

</rambling>

Re: model aircraft software
 

Then to the actual software side:

Making a simple telemetrics package to poll, store and send the GPS and accelometer data should be simple (can be done in python if you don't mind the [relatively small] overhead). This could even be sent over GPRS link.

I'm not sure whether it would be better for the N900 to push the data streams to a server on you laptop or have a simple server process on the n900 your laptop can pull the data from. Probably running a server on laptop and a simple pushing client on N900 is better (less work for the N900).

Video is more tricky, I guess you could tunnel X11 but that's about as bandwidth inefficient as it can be (though probably would be easiest to set up as a proof of concept).

Re: model aircraft software
 

What I had in mind for the first few flights was just a very simple program outputting the altitude (minus starting altitude) and the speed to the terminal, and then sshing into the phone from the laptop.

As for the video, a skype video call (or similar service) might be ok I suppose. Although I really know very little about how well that would work.

Re: model aircraft software
 

Helis crash, one needs to accept that if one wants to play with them...

I don't really know, not ever having tested but when I was first planning the video tx xfade mentioned that it might not be a good idea if I have 2.4Ghz radio (of course wifi has active interference avoidance in itself so it's different...)

You would need to run your own picocell, "theoretically possible".

yup, the problem is that suitable display goggles with sensible resolutions are still horrendously expensive.

Re: model aircraft software
 

I don't know enough about the radio systems used. But don't the Futaba radios use the faast system, hooping over many many channels very quickly. Again, I don't know nearly enough to tell whether this would make a difference.

Are you by any chance a Linux user? The hardware is there, somebody will patch support together eventually.

Yeah, having just looked into the goggles, they do seem a bit pricey. Maybe it would be easier to stick to in flight recording. A very expensive black box.

Re: model aircraft software
 

What about using something like a Nokia 6230 (nuron in the USA) which is a very cheap (£80) nokia touchscreen phone running symbian 5th edition. It has GPS, accelerometr, and ready made software with sports tracker.

damn sight cheaper than a N900 when/if it falls out not of the sky.

Re: model aircraft software
 

Among other things, I use OSX mainly and Linux (+OpenSolaris) on the side. There is some developments in open GSM basestation space but there is all kinds of regulatory issues so wifi is the realistic option.

Symbian development is pain (if we still have the goal of sending telemetrics back instead of using it as flight recorder).

Anyways for flight recorder there are lighter packages actually designed for that use.

Anyway it would be significantly lighter to use some embedded computer board with gps and wifi (or maybe just a simple serial radio link), gumstix makes those but they're a bit pricey... I have for playing around an TelIT GSM+GPS module that has bunch of GPIO pins so adding accelometers would not be an issue (though it has only GPRS, no wifi) the nice thing about the TelIT is that it runs python code (v2.2 and no floating point and some other embedded environment constraints make it slihtly painfull regardless)

Re: model aircraft software
 

"bit pricey", the consumer stuff from Vusix is somewhat sensibly priced but I have no idea how well the see-trough actually works on them (they're designed for watching movies not for HUD).

http://store.vuzix.co.uk/euro/acatalog/Wrap_920.html

And stuff designed to be usable as HUD is priced for the military and other specialist organizations:

http://www.inition.co.uk/inition/pro...e&SubCatID_=15
http://www.inition.co.uk/inition/pro...0&SubCatID_=15
http://www.inition.co.uk/inition/pro...3&SubCatID_=15

I have been waiting for ten years for reasonably priced properly HUD-capable wearable displays and while the specifications get better the price does not get much nearer the sensible range.

Edit: Some more HMD geek pr0n: http://www.inition.co.uk/inition/products.php?CatID_=8

Re: model aircraft software
 

Definitely a matter of when not if.
I've never programmed for Symbian before, I guess this is the reason why the n900 is the perfect platform for this kind of thing. The full Linux system makes it really easy.
Although a light mobile phone does seem to be pretty well suited to flight instrumentation, if one could get discrete components to communicate with a base station (perhaps the n900 itself!) it would probably be a lot cheaper when it crashes, and probably lighter in the air. In terms of getting the data to the user, a transparent hud seems like a good middle ground between regular flying and fpv flight.

I wonder how tricky it would be to get a hud system like that working; again, all the hardware is here, just easy software ;)

Re: model aircraft software
 

Checkout DIY Drones.

Re: model aircraft software
 

A n900 powered autopilot certainly would be interesting. It would have to be made fairly reliable though.

Slightly offtopic. This could lead to incredible n900fly scores though.

Re: model aircraft software
 

Autopilot would require the N900 to be able to send servo control pulses (which would require USB host mode and some sort of USB->servo thingy [these can be built form microcontrollers easily but unless you have old PIC16Fs laying around you probably would want to go with more advanced uC and then you could go to full arduino and get all you need [except python...] without using the N900).

Make no mistake: I appreciate the geek factor of doing something like this with the N900 but it's not really an optimum (or even sensible) approach to solving the autopilot (or datalogger, or telemetry) -problem. But not everything is about the optimum or even sensible solutions, look at TCP/IP over avian carrier for example...

Re: model aircraft software
 

I'm afraid you're probably right.
If a n900 to servo system could be implemented, it could be a quick testbed for ideas though. Cheaper (providing one already owns the n900) and much easier to program. A fully set up platform.

Re: model aircraft software
 

Dunno, but the requirements for this app seem to be pretty close to a 'rollercoaster tracker' app I've been wishing was available for the N900.... Track speed, altitude, video... render the whole thing in a '3D replay'... upload to the cloud... share the experience...

Develop in Qt and it should run on (some) Symbian and N900.

Re: model aircraft software
 

A relevant thread: http://talk.maemo.org/showthread.php...258#post675258

Re: model aircraft software
 

And something on HUD hardware: http://augmentation.wordpress.com/20...than-expected/

In summary: there is no see through consumer device yet.

Edit: I'm also in email disucssion with Vuzix europe representative trying to coax some info out of him (like will the display driver for the non see through stereo glasses totally freak out if one display is removed [which would allow a "glance" monocular "HUD" with one display])

Re: model aircraft software
 

I managed to fly one N900 using kites, for KAP (kite aerial photography). It was attached to the line of the kite in a rig with two servo motors (for pan and tilt). The servos were controlled by and Arduino with a Bluetooth modem, which received the pan/tilt commands from the N900. It also streamed video to another N900 on the ground, which in turn sent pan/tilt commands (created using just the accelerometers, by tilting the device) to the N900 on the kite. The Wi-Fi signal (in Ad-Hoc mode) was very good for about 150m, but after 160m or so, some video frames were being lost. For KAP purposes, the video was still good enough for about 200m or more, but I would never even try to control a model aircraft with an N900 beyond 100m! A router with more power and a good antenna could get you a wider signal range from the ground to the device on the aircraft, but it might not help as much the other way around...

This project was part of the Nokia Push contest. You can see the official blog for more information (under "More KAPing with the N900 Updates"). There is also a set on Flickr with images (and even some code) from the project.

Re: model aircraft software
 

I like the way you people think but I have only one question: Isn't this a bit overpriced? 2 N900s is like 1200E, I'm pretty sure an ATMEL could be used for controls and radio (add a radio), and a small camera could be a lot less and take (maybe) similar images.

Streaming video could also be done cheaper via analog, I assume.

Is this really the best solution out there in bang per buck?

Re: model aircraft software
 

I think you hit the nail on the head here.
It's probably much cheaper to buy the components individually. Having my n900 in a crash would be bad news.

Re: model aircraft software
 

Definitely not! But OTOH, Nokia gave me my two phones just to build my application... :D (see What is PUSH N900 for more info)

Previously I built systems using RC and video TX/RX parts, but they were not as elegant, easy to use or powerful as the one using the N900. And the N900 is so much more fun to use, too... ;)

Now I'm looking for a cheaper but similar platform (maybe a BeagleBoard or Gumstix) to use together with good compact cameras (wide angle, 12MP+ res.). It would replace the N900 on the kite, but would still stream video to and be controlled from my N900 on the ground.

Hmm... maybe I should use one N8... :)

Re: model aircraft software
 

A free kick in the groin still hurts. Err.. I mean, a free N900 still costs 600E. I can think of 5000 uses for a free N900 (with selling being #1). with the rest of 4998 being at most 2 meters off ground.

Frankly, I like your project. But I would only do it if the phone could survive crashes (tucked away).

It still sounds like a project that is warranted by "free N900s" not "free N900".

Re: model aircraft software
 

My suggestion is: don't get kicked in the groin! :p

I fly cameras almost as expensive as the N900 (which costs about US$ 500 in the US, according to a quick search). I managed hundreds of flights in 5 years, and until today I never had a crash. It almost happened once or twice (when the wind suddenly died), but even then, it was not free falling and the rig that holds the camera would have absorbed most of the impact, if not all (it is designed that way).

I can understand that... but as I said before, flying the phone on a kite is, for me, way more fun than selling it! :D

Nobody can guarantee that. There are risks involved (in anything we do, right?), but if you manage them well, you minimize the chances of an accident. And if there were no risks and no challenges, it would not be as fun and rewarding, too. ;)

Re: model aircraft software
 

I know the N900 is expensive for a cellphone, but for an autopilot, its not that bad.

I built a UAV in 2001 using an off-the-shelf autopilot that cost $5,000. For that price, the autopilot did not include a battery, GPS, or modem.

I would love to see an N900-controlled UAV!

Actually, I would really love to see someone make a USB servo controller for the N900.

Re: model aircraft software
 

We need USB host first and while there are some really smart people working on it it's not really working yet and might never be (at least without doing some hardware hacking)

BT works for interfacing with something that can generate servo controls (you wouldn't want to power it from the USB in any case)

As for other considerations: N900 is actually not a good device for autopilot or telemetry but that is not the point, the point is that it would definitely be a cool hack (a concept some people seem to have trouble understanding). Even if you would want to use python or some other interpreted language on top of non RT kernel there are better options (like the gumstix modules, though they're not cheap either), for a bit lower level there's a bunch of microcontrollers, the "arduino" platform (ATMega uC plus a bit of supporting HW and a standard layout for connecting modules designed for various tasks) being very popular for the purpose.