Which Microcontroller to use? Confused!

Thread Starter

moderns

Joined Mar 28, 2011
41
Hello Fellows :)

I am back again! Sorry for all this late as I had hard situations and relocated to my home country.

I need to start 3 rotors helicopter project and to be done at the minimal time possible, I think if I will keep asking in forums, this would take very long time, so I am thinking to ask for a paid tutor to teach me everything online and give me quick knowledge and assistance so I can finish this project very soon.

And of course I will share all the knowledge here! Do not worry.

Thanks for your kind cooperation and appreciate your interaction.
 

koehler

Joined Sep 29, 2010
3
Dude,

Seriuosly, what exactly are you trying g to do?

At first I thought you were nothing more than a lazy student who needed help with some final project. Now, I see that you've had to leave A.D. for some reason , yet are still desperately needing to get yet another remotely pilot-able craft operational in a short amount of time.

Its obviously not school related, nor most likely work either since you've been forced to move...
I'd hate to think people here were innocently helping someone in the middle-east create a UAV, for several good reasons...
Hopefully I am wrong, and this is all on the up and up. If that case there are tons of sites where you can get detailed instructions on how to build what you want without reinventing the wheel.
 

Thread Starter

moderns

Joined Mar 28, 2011
41
Sorry, I wonder the way you talk to me! Not a friendly way! I am really dead busy and I need to make my research with someone who has the experience! Not a shame! I am not asking to make for me, and what's the problem of the middle east?
 

thatoneguy

Joined Feb 19, 2009
6,359
What, exactly are you trying to build? A UAV type system might need more horsepower than an 8 bit micro can provide.

There are both PIC32 and AVR/ATmel 32 bit microcontrollers with more I/O that run much faster (80Mhz+), so more I/O can be processed, as well as math on quats if working with an IMU (Inertial Measurement Unit, 3 Axis Gyroscope + 3 axis Accelerometer).

The Arduino Due is an an Atmel ARM32 compatible processor that works with the arduino development environment (mostly).

If you plan to only have the controller assist the aircraft while being controlled from ground, such as stabilization, the 8 bit board could keep up.

When you say 3 rotors, are you referring to 3 ducted fans, on the same plane, but spaced around the central body by 120 degrees on a circle? Or are you referring to two counter-rotating rotors on a helicopter + tail rotor?

Will this be controlled from a ground unit which controls direction / altitude / attitude, or is it supposed to find it's own path via sensors and GPS?
 

Thread Starter

moderns

Joined Mar 28, 2011
41
What, exactly are you trying to build? A UAV type system might need more horsepower than an 8 bit micro can provide.

There are both PIC32 and AVR/ATmel 32 bit microcontrollers with more I/O that run much faster (80Mhz+), so more I/O can be processed, as well as math on quats if working with an IMU (Inertial Measurement Unit, 3 Axis Gyroscope + 3 axis Accelerometer).

The Arduino Due is an an Atmel ARM32 compatible processor that works with the arduino development environment (mostly).

If you plan to only have the controller assist the aircraft while being controlled from ground, such as stabilization, the 8 bit board could keep up.

When you say 3 rotors, are you referring to 3 ducted fans, on the same plane, but spaced around the central body by 120 degrees on a circle? Or are you referring to two counter-rotating rotors on a helicopter + tail rotor?

Will this be controlled from a ground unit which controls direction / altitude / attitude, or is it supposed to find it's own path via sensors and GPS?
Thanks for your reply. Actually I need to build a simple flying model.

I have Arduino Mega Chip and I have Gyroscope (out of home to get brand name) + two ESCs + 1 Servo Motor + 2 brushless motors.

I do not want to start with complicated model, I even accept to start with wired aircraft just to learn and then to go in depth.

Of course, after getting the experience of connecting devices and after being able to control rotors speed, servos, configuring Gyroscope, I will think about the GPS system to control it.

I just need to touch the base with this science! Even if the aircraft did not fly well (not stable) it will not be problem.

I need strong start and fast.

Answering your question about 3 rotors, 3 rotors will be somehow spaced around the central body.

I hope the electronics I have are enough?

Thank you!
 

Markd77

Joined Sep 7, 2009
2,806
For a normal design like a quadcopter (all rotors pointing downwards and no other control surfaces), you really need at least four independently controlled rotors.
Just one rotor - it will spin round and no way of controlling it.
Two counter-rotating motors - can be made not to spin round but can only move up and down.
Three rotors - will spin round.
Four rotors (two counter-rotating) - works fine.
 

thatoneguy

Joined Feb 19, 2009
6,359
What Markd77 stated. 3 motor only work if one of them is 90 degrees from the other two, and the first two are counter rotating (ala toy helicopters).

For a flat plane without wings or tail, you'll need 4 ducted fans, two of them spinning opposite, but still producing downward thrust.
 

Thread Starter

moderns

Joined Mar 28, 2011
41
Thanks all for your kind comments :) I really appreciate.

As Markd77 stated, initially, I need to build a simple helicopter with two rotors to go up and down only. Then the next stage is to add two extra motors and achieve the control of directions (right, left, stability) and to add more functions.

It is better to start with a simple work as I never did such work.

What do you think? I am very keen to start this project and get it live!

Thank you!
 

Markd77

Joined Sep 7, 2009
2,806
Something like this?


I'd recommend the pole to stabilise it, but allow it to rotate and move up and down a small amount.
You can add a compass, some way of detecting height, and an accelerometer.
 

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Thread Starter

moderns

Joined Mar 28, 2011
41
Something like this?


I'd recommend the pole to stabilise it, but allow it to rotate and move up and down a small amount.
You can add a compass, some way of detecting height, and an accelerometer.
Very helpful Markd77! Thank you so much!

Please could you explain about the pole?

I do not have compass and accelerometer, is it necessary at first stage work? I need to make something very simple at the beginning.
 

Markd77

Joined Sep 7, 2009
2,806
It would just be a vertical pole, fixed to your bench, going through a tube in the centre of the helicopter body. The helicopter can then spin and rise and fall, but not move sideways or tip over.
With two counter-rotating rotors as shown, to keep the body pointing in the same direction, the torque of the two motors would have to be the same. To turn to one side while keeping the same lift you need to reduce power to one rotor and increase it to the other. With this two rotor system that has the side effect of making one rotor rise, but the pole and tube will limit that. In a four rotor system the tilting can be avoided so it's not something you need to worry about yet.
For any kind of autonomous operation, the helicopter needs to know how fast and in which direction it is spinning (a compass would be ideal for this but there could be other ways for the test system).
Also some way of measuring altitude would be needed so it can know how to adjust the overall power.
<ed>Not much point for accelerometers yet, they are used to measure the tilt and that doesn't really matter for this test. </ed>
 
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Thread Starter

moderns

Joined Mar 28, 2011
41
It would just be a vertical pole, fixed to your bench, going through a tube in the centre of the helicopter body. The helicopter can then spin and rise and fall, but not move sideways or tip over.
With two counter-rotating rotors as shown, to keep the body pointing in the same direction, the torque of the two motors would have to be the same. To turn to one side while keeping the same lift you need to reduce power to one rotor and increase it to the other. With this two rotor system that has the side effect of making one rotor rise, but the pole and tube will limit that. In a four rotor system the tilting can be avoided so it's not something you need to worry about yet.
For any kind of autonomous operation, the helicopter needs to know how fast and in which direction it is spinning (a compass would be ideal for this but there could be other ways for the test system).
Also some way of measuring altitude would be needed so it can know how to adjust the overall power.
<ed>Not much point for accelerometers yet, they are used to measure the tilt and that doesn't really matter for this test. </ed>
I am greatly thankful for this detailed clarification! Still keen to know if we can go forward and backward with the two rotors model? How?
 

Markd77

Joined Sep 7, 2009
2,806
Not really, this is like one side of a quadracopter and not really useful as a flying machine.
You may have seen military helicopters that look like this, but they can adjust the angles of the blades as they spin round so they can manoeuvre.
To move forward you want the body to tilt forward so the thrust points slightly backwards. To do that you have to make one rotor spin faster which will also make the body turn. If you wanted to move backwards it would turn the other way, so there is no real way of controlling it's horizontal position.
It's still a useful learning model as controlling rotation and overall lift are things that you will need for the four rotor model and it lets you do it in a simple environment.
 

Thread Starter

moderns

Joined Mar 28, 2011
41
Not really, this is like one side of a quadracopter and not really useful as a flying machine.
You may have seen military helicopters that look like this, but they can adjust the angles of the blades as they spin round so they can manoeuvre.
To move forward you want the body to tilt forward so the thrust points slightly backwards. To do that you have to make one rotor spin faster which will also make the body turn. If you wanted to move backwards it would turn the other way, so there is no real way of controlling it's horizontal position.
It's still a useful learning model as controlling rotation and overall lift are things that you will need for the four rotor model and it lets you do it in a simple environment.
I have understood you 100% Thanks a lot.

So as start with the two rotors helicopter, what shall I do?

I have:
1. Arduino 1256 Mega Chip
2. One Gyroscope
3. Two motors
4. Two ESCs
5. One Servo Motor

Do I need extra equipments?
 

Markd77

Joined Sep 7, 2009
2,806
That should do for starters. You can use wires to control it for now until you start using wireless control. Without an accelerometer or any way of sensing height you can just use a potentiometer to control overall power so up and down would be under manual control, but with the compass you can get it to control it's own direction.
I guess it's time to start building and coding.
 

Thread Starter

moderns

Joined Mar 28, 2011
41
That should do for starters. You can use wires to control it for now until you start using wireless control. Without an accelerometer or any way of sensing height you can just use a potentiometer to control overall power so up and down would be under manual control, but with the compass you can get it to control it's own direction.
I guess it's time to start building and coding.
Thank you Mark. So the ESC's cannot control up and down or power?

I will check the compass online.

I will start very soon and if I am allowed I will be posting my progress here with photos, so beginner can learn. Also, will be getting your advice on same thread. Shall I start a thread for my project including the whole work progress / issues, what do you think?
 

Markd77

Joined Sep 7, 2009
2,806
I've just reread the thread. For some reason I thought you wanted to build something that flies itself, but you are trying to make a remote controlled quadracopter.
Sorry that some of my posts have been a bit confusing.
This explains pretty well what all the different types of sensors are for:
http://diydrones.com/forum/topics/quadcopter-control-function-layers
For remote control you still need a three axis gyroscope because they can react quickly to to changes in tilt and heading and prevent a crash. Human reactions aren't quick enough to do that. An accelerometer would also be nice to have (but not essential) because it can react to changes in altitude and correct them, and also mean that the quadcopter can know which way is up. The compass isn't really needed for a manually controlled quadracopter, but it's nice to have to stop the inevitable slow spinning due to inaccuracies in the gyroscope.
For now you can use the compass instead of a gyroscope for corrections to the direction it is pointing in.
It's up to the microcontroller to tell the ESCs how fast to spin the motors, and the total amount of power to the rotors will be under your control, possibly with some help from the accelerometer.
 

Thread Starter

moderns

Joined Mar 28, 2011
41
I've just reread the thread. For some reason I thought you wanted to build something that flies itself, but you are trying to make a remote controlled quadracopter.
Sorry that some of my posts have been a bit confusing.
This explains pretty well what all the different types of sensors are for:
http://diydrones.com/forum/topics/quadcopter-control-function-layers
For remote control you still need a three axis gyroscope because they can react quickly to to changes in tilt and heading and prevent a crash. Human reactions aren't quick enough to do that. An accelerometer would also be nice to have (but not essential) because it can react to changes in altitude and correct them, and also mean that the quadcopter can know which way is up. The compass isn't really needed for a manually controlled quadracopter, but it's nice to have to stop the inevitable slow spinning due to inaccuracies in the gyroscope.
For now you can use the compass instead of a gyroscope for corrections to the direction it is pointing in.
It's up to the microcontroller to tell the ESCs how fast to spin the motors, and the total amount of power to the rotors will be under your control, possibly with some help from the accelerometer.
Thanks Mark for the rich details :) No worries. Actually I was planning to do an advance one (quad with GPS, etc.), but because I am new to this field, I prefer to start with the simplest model and then to upgrade (step by step).

So I will be starting with the two rotors model and I hope to finish it in 1 or 2 month. I will be using wired control instead of the GPS.

I need to start the work but confused from where? Can I start a thread and add my progress there with photos and explanation to all members? I will be in need for your inputs as I am newbie :)

I saw the video, it is brilliant and hopefully to build such aircraft after finishing the simple one. Thank you.
 

Markd77

Joined Sep 7, 2009
2,806
You could start a new thread or continue this one.
If you start a new one, please scan through this thread and include all important details in the first post (including links to motors, ESCs, sensors, microcontroller) and what you are trying to achieve.
It saves people from scanning through both threads. Also put a link to this thread just in case.

This picture is for no real reason, I'm just trying to learn how to use Blender:
 

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Thread Starter

moderns

Joined Mar 28, 2011
41
You could start a new thread or continue this one.
If you start a new one, please scan through this thread and include all important details in the first post (including links to motors, ESCs, sensors, microcontroller) and what you are trying to achieve.
It saves people from scanning through both threads. Also put a link to this thread just in case.

This picture is for no real reason, I'm just trying to learn how to use Blender:
Thank you very much Mark for this. I believe starting new thread with full details would be better as people can spot the correct subject. Under which section it should be?
 
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