Multirotor, multicopter and quadcopter discussion thread (drones).

Soldato
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Inspired from the single rotor thread and RC plane thread. I have decided to make a multiroter thread.
Many people already know that I am in the process of building a quadcopter. So far I have finished the frame with help from my dad and others. Now I am just pondering over the electronics required for it.
I have done a lot of research, even though I have not built one yet I am happy to answer any questions.
This is an upcoming area of controlled flight so I will walk you through the basics of what is involved.

Frame:

In terms of aerodynamics, the frames design does not have much effect.The rule of thumb is that you need 4 rods of a strong material that connect to a central point. Such as this
664V1.jpg

Lots and lots of designs, can be made from as little as £15 ( this is what I did) up to £50 depending on what material you want. Also size can be from massive to small. Some people have successfully built 3" frames ( sorry for imperial units, I read rc groups which is a US site)
The most important thing is that you need even weight distribution and you really want some sort of carbon that you land on and absorb the impact.

Motors:
All depends on the size and weight of the frame and electronics. I have not done many calculations and have just gone for emax 2822. Some people want their quadcopters to be very agile so they put a lot of work in deciding which ones to get. In most cases, if you pick up a 800 kv motor with 8" props it should be fine.

Speed controller:

Turniqy/Hobby wing are good. You need to get the same speed controllers so that you get even feedback across all motors. Also they need to be programmable and at the right ampage for your motor.

Electronics:

Probably many of you are wondering how the hell these things are controlled. It's all thanks to some electronics wizzadry. Basically there is a flight controller which takes signals from the receiver and outputs signal to the motors to make them the right speed to do what you want. One of the most popular platforms is multiwii which is an arduino controlled system. Usually ran off arduino pro minis. They then have sensors which allow the flight to be stable. Also lots of other nifty tricks such as direction hold, gps hold, altitude hold. Most people usually use these sensors
ITG3200 -Gyroscope.
BMA180 - Accelerometer.
or take them from wii remote controllers and nun-chucks.
Multiwii is not the only system, many chinese cheap knock offs are around that mean you can get a system for under £10 ( hobby king board for example). These are generally harder to fly.
Besides that there is ardupirates which is very advanced and powerful, also there is open pilot which is cheap but they have supply issues.
Multiwiicopter is a good place to get all the electronics, the sensors are very well priced and they sell everything you need excluding the arduino pro. Giant cod is a great place that has UK stock as well.

What can you get out of it?
With a bit of tweaking, adding a camera and some very expensive electronics you could get something like this
http://vimeo.com/21494540
http://vimeo.com/18873955
Be aware that, that kind of stuff is not achievable for under £150, but this kind of stuff is ( well he is using ardupirates, it's more expensive than multiwii but the same sort of things can be achieved with multiwii)
http://vimeo.com/20597641
http://vimeo.com/21494540
Hopefully, I will have pictures and videos of my project up in the next few weeks.
Cheers and fly safe.
 
Soldato
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Right, I have ordered a wii motion plus. Arduino nano will be coming from the bay and I will probably put a massive order in from hobbyking.
 
Soldato
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Excellent. :cool: How much does the frame weigh?

Once I get out of my obsession with RC Planes, and I'm going down the FPV route with that, then I really want to give a Quadcopter a go.
 
Soldato
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Excellent. :cool: How much does the frame weigh?

Once I get out of my obsession with RC Planes, and I'm going down the FPV route with that, then I really want to give a Quadcopter a go.

I think it was 12 OZ, not sure though.
I have just finished soldering the wii mp+, damn it is flipping hard. Pro tip though. Tin the wires a lot, makes it much easier to get a clean join.
 
Soldato
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Damn, want one of these now :(:o . Realistically, going to have to travel some way to get any views as scenic as in those videoes though, and knowing this country, it's probably illegal to fly one fitted with a camera anyhow. Might be possible in some forests or quiet parks though.

Good luck with the build! Will you be fitting a camera? If those speed controllers are expensive then I'd suggest that they are very simple to build btw. In fact, the controller will be able to output PWM directly so it's really just a pass MOSFET that's needed.
 
Soldato
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Damn, want one of these now :(:o . Realistically, going to have to travel some way to get any views as scenic as in those videoes though, and knowing this country, it's probably illegal to fly one fitted with a camera anyhow. Might be possible in some forests or quiet parks though.

Good luck with the build! Will you be fitting a camera? If those speed controllers are expensive then I'd suggest that they are very simple to build btw. In fact, the controller will be able to output PWM directly so it's really just a pass MOSFET that's needed.
It's completely legal :), though if you are flying in crowded areas then it's best to make it ducted so that no one gets their arms cut off. I will probably be fitting a camera, probably one of those key ring cameras. Maybe go for a proper stabalized system later on, iirc multiwii can do stabilization as well.
 
Soldato
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Done the NK
xylAcl.jpg

Neither my dads gas soldering iron nor my electric jobby was good enough to melt the solder on the board, so I just had to solder over the top of it. Bit annoying, but hot glue will secure it down fine.
 
Associate
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I have an arduino nano sat next to me, Can you do a parts list of the boards, motors and any extra things youve used, this looks like a fun summer project :D
 
Soldato
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I have an arduino nano sat next to me, Can you do a parts list of the boards, motors and any extra things youve used, this looks like a fun summer project :D

Hobbywing 18A ESC *4
Wood from hobby craft
4 carbon rods
4 Emax 2822 Motors
Arduino nano
Wii motion Plus
Wii Nunchuck
Futaba Receiver
2300ma battery ( I think, I can't remember though)
8" Rotating and counter rotating props
4 Prop adapters ( 3mm)
Gold connectors
Male to male Servo leads

You need other general stuff though, such as soldering iron, flux, solder and electrical wire.
 
Soldato
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Make sure you have motor controllers that run at 500Hz or more, and buy the best gyros & accelerometers you can afford for the attitude controller.

But TBH, just buy a a AR Parot.
http://ardrone.parrot.com/parrot-ar-drone/usa

cheap as chips, incredibly stable flight.

They are incredibly stable, but they have low range and the acceleration is poor. I think they use low rpm motors so that they don't cut your hands off. You can build a much better quad for a lower price, that is unbelievably fast such as this
 
Caporegime
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i wonder what would happen if you got 4 helicopter frames and connected them in the middle by the booms.

that way you would have actual gearing on each motor and blades which spin much faster than just the motor itself can turn


i bet you could get 100mph vertical acceleration easy :D, 250 helis usually have a headspeed around 3800-4400rpm
 
Man of Honour
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My old housemate built one of these and designed all the electronics / control devices for it during his engineering degree.

He then proceeded to test it in the loungue with spinning metal blades of death everywhere. Needless to say, me and icecold were terrified :eek:
 
Caporegime
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all my heli stuff arrived and its quite daunting! maybe i should have done a quadcopter lol they look so much simpler, no pulleys , drive trains , no need for four servos etc
 
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