How cheap can one build a GPS-guided semi-autonomous model aircraft?

[aero_k]

I'm really interested in building a simple UAV, but I'm a little concerned about the costs associated with it, since I'm still a University student with little-to-no income. Is sub-$200 possible?

At this point I would be happy with something that I can plug in some way-points, have a fixed-wing UAV fly some circuits autonomously, then come back. I've spent some time looking at some threads here and at DIYdrones and it's still a little confusing to me. I have to admit that I'm not very good with electronics, computers, and programming, but I really want to learn.

From what I've seen, it looks like I could buy something like Ardupilot, an FMA Co-pilot, GPS module, and necessary hardware for between $100-200. Am I missing something? Am I going to need to do some complicated programming and soldering? I assume there's a tradeoff (there always is) between cost and simplicity. A plug n' play system is probably going to cost me some bucks.

I hate to sound like one of those "Someone tell me a good beginner RC plane" people, but I also would like some advice on where to start. I've been flying RC for over two years and I more or less know my way around them, so I've got that much covered. Now what? I'd hate to just go buy everything and not know what the heck to do with it. Maybe I should start with a co-pilot and see how that works, or maybe diving in head first is the way to go...

Thanks for taking the time to help an aspiring UAV designer out :)

[zlite]

Assuming you already have a plane and a 5-channel (or better) RC system, I think the cheapest is this:

--ArduPilot (https://www.sparkfun.com/commerce/product_info.php?products_id=8785)($24.95)
--GPS (http://www.sparkfun.com/commerce/product_info.php?products_id=465)($59.95)
--XY (http://www.fmadirect.com/detail.htm?item=1778&section=20)and Z (http://www.fmadirect.com/detail.htm?item=1888&section=29)sensors ($42.95 + $24.95)
--A USB-to-serial board (http://www.sparkfun.com/commerce/product_info.php?products_id=9115) to program it with ($13.95)
--Some connectors, as given in the Sparkfun listing (http://www.sparkfun.com/commerce/product_info.php?products_id=8785).

That's about $175.

You'll need to do some very simple soldering (nothing harder than what you already have to do with a brushless motor or ESC). No programming required, although you will have to load the code with the easy-to-use (and free) Arduino software.

[dmgoedde]

Thanks to Chris and Jordi at DIY Drones, these are the very first months that would-be new UAV enthusiasts have a real shot at low cost systems that work for a variety of planes. I know of no other system or way to do it as inexpensively. 6 months ago the thread started would be met without a good reply.

[airmcn_3]

6 months ago the thread started would be met without a good reply.


There is a lot of truth to that statement........ Hard group here sometimes.....

[rich smith]

I can verify that it's possible to build these for under $100 from off the shelf parts and half that if you are a good shopper. GPS is the most expensive component and ranges from $20 on ebay to $70 from places like Sparkfun. Computer runs about $2, couple servos $3 ea. Battery and ESC about $6 ea. RX is optional but goes for $14 shipped. A self-stable foamie type plane with CF fuse and PB3 wings can be built for <$5.

There are a dozen or so DIY designs on the net but be aware they generally tend to underestimate expense and effort required. Browse the threads to get the picture. Actual difficulty depends on your own experience and cost appears to be inversely proportional to this. Someone with neither experience nor time can expect to pay about a grand to get one going.

I'm really interested in building a simple UAV, but I'm a little concerned about the costs associated with it, since I'm still a University student with little-to-no income. Is sub-$200 possible?

At this point I would be happy with something that I can plug in some way-points, have a fixed-wing UAV fly some circuits autonomously, then come back. I've spent some time looking at some threads here and at DIYdrones and it's still a little confusing to me. I have to admit that I'm not very good with electronics, computers, and programming, but I really want to learn.

From what I've seen, it looks like I could buy something like Ardupilot, an FMA Co-pilot, GPS module, and necessary hardware for between $100-200. Am I missing something? Am I going to need to do some complicated programming and soldering? I assume there's a tradeoff (there always is) between cost and simplicity. A plug n' play system is probably going to cost me some bucks.

I hate to sound like one of those "Someone tell me a good beginner RC plane" people, but I also would like some advice on where to start. I've been flying RC for over two years and I more or less know my way around them, so I've got that much covered. Now what? I'd hate to just go buy everything and not know what the heck to do with it. Maybe I should start with a co-pilot and see how that works, or maybe diving in head first is the way to go...

Thanks for taking the time to help an aspiring UAV designer out :)

[aero_k]

Thanks for the responses, it looks like my timing is good, and so are my chances of not going broke trying to build something. I've done several scratchbuilds, I have a 6ch radio, servos, rx already, so I'm okay there.

I'll do some more in depth reading on the Ardupilot and Arduino, and I think it will eventually sink in. I started reading the Paparazzi wiki for some background, since I assume it would be generally the same.

I'm done school in a week, so I'll make this a summer project, but it will probably go long past the summer. I think I have a few friends who might be interested in getting involved as well. If I'm lucky, I can spin it as educational and maybe I can get the school to pay for some of it (not likely) since I'm starting Grad School in May working on MAV's.

We're using Micropilot and Horizon for a large UAV we are building as a school project (16ft wingspan, 200 lb), but that stuff is way too expensive for me to tinker around with a this point. I don't know too much about it since I was involved in the manufacturing of the UAV, not really the avionics.

[macboffin]

Would like to point out what a UAV is about. It is an aerial cost effective solution to various problems of data acquisition, usually but not always to military tactical information, or to civil land surveying for various purposes. Design starts with the payload which will deliver the required result, the electronics and their power supply necessary, adequate power and it's battery/fuel supply for the range and duration wanted. The airframe design will reflect the range of weather conditions likely to be encountered in operation , transport and storage etc. There may also be constraints (for Government work) on sources of supply of materials and components, on specified numbers of disabled workers involved in manufacture etc etc. A model airplane with GPS and live video is nowhere near a UAV!.

[workshop]

You sound like a record company tellin' the kids that an iTune is not the same thing as an LP*. ;)

Jeff

* an LP is an analog audio recording pressed into a large flat vinyl disk. Similar to what DJ's use today for scratching.

[aero_k]

Fair enough, for now I would like to build a model airplane with GPS, but eventually I would like to use the knowledge gained from that experience to design and build a "UAV", whether it's through school for entering in competitions, or as a career following graduation. This, I guess, is just the first step to an eventual UAV. I agree, for now this is just a "smart" model aircraft.

I'm somewhat familiar with the design and manufacture of UAVs. The one we are building at school is for Geophysical Survey, and was designed and built to a fairly strict set of requirements. We are also in the process of obtaining an SFOC from Transport Canada to fly it this summer (fingers crossed). I suppose mine, however, would not be a "UAV"; I just got loose with the terminology.

Either way, this seems to be a great place for the information I'm looking for, and I appreciate everyone's feedback. Keep it coming!

[waqa]

I've taken the low budget route in my UAV adventure. I am still flying it without the CoPilot but plan on adding one later along as funds permit. My UAV consists of:

-Dollar Tree Foam 30inch Trainer (about $2+some hot glue)
-ArduPilot+GPS ($85),
-cheap 6 channel chinese radio+receiver ($42)
-HXT500 5g servos ($10)
-24g Motor ($8)
-10A Turnigy ESC ($12)
-Zippy 2S 800mah ($7).

Total cost: $163

All up weight with 1oz camera is just under 10oz. It flies well in up to 7mph winds. The airframe is stable and flies fine without the CoPilot on low wind days. I've added a 'cameraon' element to the waypoint array to turn the camera on and off between chosen waypoints. I'd also like to add an Xbee ground station link later.

If it wasn't for the ArduPilot I would not be able to enjoy using and learning about UAV's.

Choose what suits you and work your way up. It's all fun.

I still get a kick every time I hit the auto switch :D.

[rich smith]

A model airplane with GPS and live video is nowhere near a UAV!.

Technical that is incorrect. FAA defines UAV, Unmanned Aerospace (not Autonomous or Aerial) Vehicle, as ANY vehicle without pilot on board. In fact by their definition all RC models including chuck gliders are included. Autonomous, cameras, missles, GPS, or not.

[Airboatflyingshp]

If you need to build an airframe the cheapest and quickest route is to use SPAD construction and Correx, blue foam brown paper and anything you can beg borrow or scavenge ..plans are free check out the relevant sections and the AP thread in particular..... you can even use Cardboard if you water /fuelproof it.. get Wombling! Now I am showing my age and cultural roots!

Your power plant is the next most costly item after your electrickery but that depends on size and payload, keep your wing loadings moderate to light unless you want life to get complex/expensive fast and pick a design thats fairly stable in the air .......electrickery thats your ball game.

[aero_k]

I've been scratch building from Elmers foam board for a little over a year, and I have several cheap motors and escs and a handful of cheap servos around. I've managed to build about 5 different planes, all for less than $20 each. I've never tried a SPAD though, it seems quite a bit tougher than the thin foam, but probably not as light.

What I wasn't sure about as the autopilot, GPS, and software. Seems like it can be done cheap, which is good. I though you needed a co-pilot, since it "steers" the plane... maybe I'm confused about that. What does the co-pilot do again?

Another question: how small of an area can the "UAV" fly? Can you keep it within, say, a football field or two? Obviously I wouldn't try flying in a small enclosed area, but I'm just wondering how small of an area your way-points can be.

[zlite]

What I wasn't sure about as the autopilot, GPS, and software. Seems like it can be done cheap, which is good. I though you needed a co-pilot, since it "steers" the plane... maybe I'm confused about that. What does the co-pilot do again?


If your autopilot doesn't have a stabilization function (ie, it just does GPS navigation), a Co-Pilot can provide that. But all the autopilots discussed here have built-in stabilization and don't require the Co-Pilot.

[Airboatflyingshp]

Look in at this thread for the links I already posted http://www.rcgroups.com/forums/showthread.php?t=1037389, Corex can be a bit heavy but if you want a big platform and speeds not a problem take a look at Mud Ducks aviation... Ok maybe thats going too far ?? but take the construction principles and build a more conventional slimmer fuse use Foam board or Correx ...look at the spad guys larger gliders, think flying box car.

[aero_k]

I'm still wondering, how small of an area can the "UAV" fly? Can you keep it within, say, a football field or two? Also, what is the general sensitivity of altitude measurement and control? Can the Autopilot distinguish 30ft vs 100ft?

Basically, could you set up the aircraft to fly circles around a football field at 30ft?

[rich smith]

The lat/lon accuracy of the GPS is in the order of a few inches so minimum flying area is more determined by the plane. A light weight slo-fly plane with low wing loading can navigate in very small spaces. My 48" foamie flies quite well under GPS control within a 200'x200' school size soccer field as you can see in the Delorme map in my GPS/XB thread:

http://www.rcgroups.com/forums/showthread.php?t=993165

Unfortunately this type of plane is not popular with most of the DIY UAV crowd. They prefer Funjet and other high speed high designs because easier to control in wind. You need much bigger space for those and since I do not have access to even football size I stick with predawn tests in very small fields.

GPS latitude accuracy is a whole different story. While they seem to do fine most of the time there is huge variabilty in accuracy ocassionally. I've observed random drifts in the order of 850'. Some of the low cost DIY guys who are depending on GPS altitude may be in for a big surprise some day.

The only accurate type is barometric pressure sensor which increases cost of control systems big time. Another solution, which I have adopted, is to stay at least 1200' up. :eek:


I'm still wondering, how small of an area can the "UAV" fly? Can you keep it within, say, a football field or two? Also, what is the general sensitivity of altitude measurement and control? Can the Autopilot distinguish 30ft vs 100ft?

Basically, could you set up the aircraft to fly circles around a football field at 30ft?

[aero_k]

That sounds great. I'd like to use something slow that will stay close to me, especially while I'm learning how everything works. I've got a fairly big field to fly in, but it would be nice to keep it close if I want. I looked at your thread, but at this point not much of it made any sense to me. I still have lots of learning to do...

[rich smith]

Note that slo-fly does not come without drawbacks. You are limited to windless conditions.

Main item of interest in that thread was flight pattern within couple hundred feet. The plane will fly figure eights in 50' x 100' but not after sun comes up. My delta able to fly in very high wind but not as stable or efficient as the 48". Something in between those extremes might be best.


That sounds great. I'd like to use something slow that will stay close to me, especially while I'm learning how everything works. I've got a fairly big field to fly in, but it would be nice to keep it close if I want. I looked at your thread, but at this point not much of it made any sense to me. I still have lots of learning to do...

[aero_k]

Yeah, thats basically what others have told me. Either I fly in a small area with a slow plane in zero wind, or fly in a large area with a fast plane in higher wind. Maybe I'll go for medium area, medium speed, and medium wind?? A little more weight and size will handle the wind a little better too.

[aero_k]

Another question:

-Do you have to have a ground station (i.e. a laptop) at the field when flying the "UAV"? Or can you pre-program everything, then go fly without a ground station?
I apologize for the noob questions, but I'm sure there will be other noobs that could benefit from this information too...

[Airboatflyingshp]

Seriously :) Take a look at Mud Duck Aviation look at the Sport versions with the 82" span they are virtually STOL and stall resistant they can carry big bulky loads no prob and they do slow 16mph :eek: or very slow :rolleyes: , but they handle winds as well.... they are very stable platforms. If you can scavenge some foam board signs that are not vinyl covered then you get your main building material free. :D
Speak to Greg and look at the videos of the AP/UAV? version.Thats a full size 108" span one :cool:http://www.mudduckaviation.com/ do the job have fun and no worry about getting it all into a tiny fuse.

[MudDuckAviation]

Aero_k,

Let me know what kind of power set ups you already have and I will scale down a set of my plans that will accomodate the gear you already have and your anticipated payload. I'll send you the plans for free.

Since you are already familiar with working with foamboard, these plans (and the manual) will be right up your alley. If you can get your hands on some FFF (BlueCor) from any house construction around you it is even better for a smaller version (it's stong enough and it weighs 1/3 as much as foamboard).

I can also let you know how to make a spare wing that will be better for windy days but still provide you with slow enough flight.

Here is the down-linked video Mud Duck that Airboat was referring to: Video (http://www.mudduckaviation.com/video/Dan%20Thompson's%20coverage%20.mpg) Although not GPS guided and it's 108" w.s., it gives you an idea of the plane, we can just shrink it down to meet your need.

here is my videos page that shows you how the (larger) plane is assembled http://www.mudduckaviation.com/Pages/Videos.htm

Good Luck!

Greg

[rich smith]

Do you have to have a ground station (i.e. a laptop) at the field when flying the "UAV"? Or can you pre-program everything, then go fly without a ground station?


I've succeeded in flying small patterns fully autonomous without GPS or ground station which AFAIK has never been done here at RCG. Normally you want feedback so a notebook running Google Earth GPS version is what most guys use to track their plane.

Personally I have an Asus EEEPC running Delorme for tracking and recording because a full size notebook is too bulky for my motorized bike. If pedalling then a tiny HP 200LX running MSDOS with PROCOMM PLUS is used to record but no realtime tracking.

[Airboatflyingshp]

Greg your stalking me................ LOL
Im consulting bodies over my power options and trying to stay awake enough to concentrate on one thing.

[aero_k]

Wow, thanks for the help, once again. As much as I would love to build one, I don't think an 82" span would fit in my apartment! Plus I carry everything I fly across the street to the field, so it might be a little cumbersome too. Everything I build is less than 40" (for the reasons above), and electric. Anything that size is easy to get an appropriate motor for at reasonably low cost. I would probably be mounting a standard size point-and-shoot digital camera for payload. I would really appreciate the plans, it looks like a cool bird. I might have to call it a duckling though...

So as far as the ground station goes, it serves more for tracking your flightpath and displaying/recording things such as speed, altitude, position, etc. If I don't really need to know that stuff, I could get away without one?

[Airboatflyingshp]

AK a Secret all the ducks are very domesticated ;) and scaleable by greg - the wings are QD on spring pins and as I said you could build a simpler more streamlined shaped fuse in a W/E. http://www.rcgroups.com/forums/showthread.php?t=613143

[MudDuckAviation]

Wow, thanks for the help, once again. As much as I would love to build one, I don't think an 82" span would fit in my apartment! Plus I carry everything I fly across the street to the field, so it might be a little cumbersome too. Everything I build is less than 40" (for the reasons above), and electric. Anything that size is easy to get an appropriate motor for at reasonably low cost. I would probably be mounting a standard size point-and-shoot digital camera for payload. I would really appreciate the plans, it looks like a cool bird. I might have to call it a duckling though...

So as far as the ground station goes, it serves more for tracking your flightpath and displaying/recording things such as speed, altitude, position, etc. If I don't really need to know that stuff, I could get away without one?


http://www.mudduckaviation.com/zen/images/MDA/Held_small.jpg

This is the CricKit... 33" and if built from FFF or depron can fly on a very small inexpensive motor. The only catch with this one is I have to re-draw the plans yet.

I can easily scale a Mud Duck down to 30", 40", whatever you want. 36" would be 1/3 scale from the big one. If you have a power set up for a 40" plane, it will be right at home on the 36" version. If you build the wings like the big one (2 halves that attach to the fuse like a real plane) then you only have to store two wing halves less than 16" long.

Greg your stalking me................ LOL
:eek:
I saw the links from this thread on my stats page for my website. I always checkout new posts linking to my site to see what new is going on (that is, when I catch the links). ;)

Greg

[aero_k]

Removable wings would be great, and 36" inches sounds just about right for my current living conditions and budget - its hard being a university student and into RC at the same time!

[MudDuckAviation]

Shoot me an email at mudduck@optonline.net and provide your name and mailing address and I'll get a set out in the mail by this weekend.

Greg

[aero_k]

Sent. Thanks Greg :)

Okay, so I'm getting closer to actually making some purchases. It looks like the Ardupilot 2.x is the way to go. I wont need the co-pilot, and it uses aileron/elevator rather than rudder, which I like. I'm reading all the instructions on the DIY drones site so I know what I'm getting myself into. I'm sure I'll have questions, so stand by...

[aero_k]

Okay, after some reading it looks like I only need a GCS if I'm transmitting telemetry with something like an Xbee wireless module, but this isn't required to fly, correct? i.e. I can fly without transmitting anything back to me from the aircraft. Although having a ground station to show where I am and what the aircraft is doing would be very useful, I just don't feel like forking out the cash for it yet. I'll start with the bare minimum and get comfortable with that first I think, then go to that step. Any objections?

[rich smith]

If you're made of money skip the plane tracking system. Otherwise get that running first before you start playing with autonomous flight stuff.


Okay, after some reading it looks like I only need a GCS if I'm transmitting telemetry with something like an Xbee wireless module, but this isn't required to fly, correct? i.e. I can fly without transmitting anything back to me from the aircraft. Although having a ground station to show where I am and what the aircraft is doing would be very useful, I just don't feel like forking out the cash for it yet. I'll start with the bare minimum and get comfortable with that first I think, then go to that step. Any objections?

[aero_k]

If you're made of money skip the plane tracking system. Otherwise get that running first before you start playing with autonomous flight stuff.

Do you mean, if I'm NOT made of money (which I'm definitely not) skip the plane tracking system, or are you saying that I should start with the tracking system (Xbee) and get it working on the ground, then try to put it in the air? Maybe I'm misunderstanding...

[HELModels]

I'm finding out that the incidental costs will drive up the price. When you get your Ardu, check the GPS cable to make sure all pin positions are clear and open. That little $2.00 cable had some flashing blocking the Gnd pin. It pushed the pin out of the way instead of accepting it. I ended up buying a special programmer for $45.00 after shipping so I can check the condition of the chips. Was that really a necessary purchase? I might end up buying a new Ardu board in the end - mo money, mo money. It's these kinds of unexpected costs that drive up costs in the end.

[bolkow]

I'm also planning to embark on the same project. Just like aero_k, I'm still in the process of researching what stuff to get. I can scratch-build model planes so the platform is no longer a concern, but the design depends on the payload. Basically, I plan on the following in one system:

1. autonomous flight
2. FPV flying
3. a separate camera (independent of FPV) that moves on all axes and remotely controlled including the zoom capability
4. telemetry, for realtime video and flight information

Here goes more stupid noob questions as I've not read it asked before, please bear with me:

Am I correct to assume that the ardupilot and accessories should address No. 1 and eagle tree system should take care of No. 4 or does the ardupilot also support telemetry? What do I need to achieve Nos. 2 and 3?

I understand you have to pre-program the waypoints to the ardupilot. I also know that on take offs and landing, the aircraft should be RC controlled. How do you switch between RC to autonomous then back to RC?

What is the range that the "UAV" can be flown autonomously with the stock Tx-Rx hardware? Can the range be increased with hop-ups?

WHat other hardware do I need?

Can electric flight be possible for 2-3 hours of operations?

The application shall be to survey protected land and see if there are illegal settlers/poachers, etc. A cheaper alternative to flying out a full-scale light helicopter. The emphasis on CHEAP. :(

Thanks in advance.

[aero_k]

Hey bolkow, it's nice to have company. I think I can answer some of your questions (others correct me if I'm wrong):

Am I correct to assume that the ardupilot and accessories should address No. 1 and eagle tree system should take care of No. 4 or does the ardupilot also support telemetry?
I believe Ardupilot supports telemetry, but you need to be a wireless module like a Zigbee (xbee). Maybe thats what EagleTree is? More here: http://diydrones.com/profiles/blogs/adding-wireless-telemetry-to

What do I need to achieve Nos. 2 and 3?
No idea, but I'm interested in hearing the answer from the "experts"

I understand you have to pre-program the waypoints to the ardupilot. I also know that on take offs and landing, the aircraft should be RC controlled. How do you switch between RC to autonomous then back to RC?
You can switch between manual control and autopilot using a toggle switch on your Transmitter. I believe you can also switch between Waypoints, Return-to-home (plane flies back to where it started on its own), and Fly-by-wire (manual control with auto-stabilization) using a 3-position toggle switch, which I think is pretty cool. At this point, I don't know how to to that though.

There's a lot of information here: http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A44814. Go through all the "instructions" links about half way down, they are fairly clear (even I can mostly understand them!).

I'm not sure about range, but I think 2-3 hours could be achievable with an efficient airframe and high capacity batteries. Thats not really dependent on the autopilot, but how much power you can pack into the plane and get it in the air.

Hope that helps, and I hope everything I said is correct, since I'm still learning too...

[bolkow]

Thanks for your inputs aero_k. I've also done some surfing since I last posted and also stumbled upon the diydrones site. I saw the " A Newbies Guide to UAV's" posted by Chris Anderson and while it's still under construction, I learned that I'm on the right track in my research.

My intent is more than hobby application, sort of semi-industrial use as mentioned in my previous post. I'm looking for a more robust system, but for the prototype, cheap components will do just to prove that the system works and doable in the initial test flights. Will probably upgrade later as personal funding permits. I.E. for now, I'm looking at thermopile-based stabilisation system, then probably get an IMU system later as redundancy. I don't want to jump into the expensive stuff immediately while still learning the ropes.

Great thread BTW.

Some people may already have done a similar project. Does anybody know the rough estimate of the weight of the complete system (payload) I mentioned (excluding the airframe and radio equipment to fly the RC aircraft manually)?

[aero_k]

Looks like your are indeed on track. I wish I had a practical application for my "UAV", because it really guides the design process, but I just can't seem to find one! I'm just interested in learning about the technology so when I do have a practical application I'm ahead of the game. Maybe it will help me get a job after I finish grad school too!

[rich smith]

IMO it's more important to be able to track your plane before sending it off on it's own. In my case the additional cost of an XBee module paid for itself several times over. And yes, it's not only vital to test the tracking system on the ground but also the autopilot code itself.

Do you mean, if I'm NOT made of money (which I'm definitely not) skip the plane tracking system, or are you saying that I should start with the tracking system (Xbee) and get it working on the ground, then try to put it in the air? Maybe I'm misunderstanding...

[aero_k]

Yeah, I was thinking about that last night and it started to make sense. I can start by flying under manual control and track the plane and make sure the correct data is coming back, then move up to Fly-by-wire, then go to pilot if everything seems to be working. Good point.