Quadcopter with zero microprocessor :D

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Quadcopter with zero microprocessor :D

Postby ayadabd000 » Mon May 27, 2013 1:22 pm

Hello,

I'm new to the RC world and I have an interesting project I need to accomplish for my digital class in three weeks :D

I have to build a very very very basic quadcopter without the usage of any microprocessor at all. That means I won't be able to use the ESC for the brushless motors.

My main question is, can I use the brushless motor without ESC ( that is by 555 timers or else?). All I need is power the motors to full speed, I don't need speed control. Is that possible at all?

If not, what kind of good brushed motors I can use?
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Re: Quadcopter with zero microprocessor :D

Postby BillGriffiths100 » Mon May 27, 2013 5:40 pm

A brush-less motor requires sensing and timing best accomplished by a microprocessor, a hardware version would be very cumbersome and require a long time to develop (besides being almost useless).
Controlling a quad copter requires a lot of processing and in that it senses accelerometers and gyros, a hardware version of that would be very difficult to make and take a great deal longer than three weeks, developing software would probably took a great deal longer as well!
Brushed motors would be your only hope such as :
http://www.modelmaniacsonline.co.uk/pro ... de=5510370
Brushed motors don't have the torque of brush-less out-runners normally used and won't have the power you are hoping for so that will be a problem.
Speed controllers for brush-less are fairly simple and can be made with a few integrated circuits providing a pulse width modulation and some FET's, there used to be a fair number of circuits you could find
http://www.sentex.ca/~mec1995/circ/circuits.htm
Stabilisation would have to rely on just physically stabilising with a weight .
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Re: Quadcopter with zero microprocessor :D

Postby ayadabd000 » Mon May 27, 2013 6:39 pm

yeah I know what you mean, but I have no option..

I have an idea, but I don't know if it will work or not..I was thinking of building the quad with 8 motors: 4 brushless running with full power to help lifting the quad, and 4 brushed which I can use to control the quad, do you think that's realistic??

If so, which circuit could be used to run the brushless motor with full power ( no speed control)
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Re: Quadcopter with zero microprocessor :D

Postby BillGriffiths100 » Tue May 28, 2013 9:16 am

Good idea but I think a hardware brush-less is probably out of the question given your time scale even if it was fixed frequency, now is the time to ask "is this project being made deliberately impossible.. what is the mental capacity of the individual setting this task could they do this themselves in the time allotted?"
With three or four people skilled in the subject each working on a part of the task full time perhaps...?
Do they expect you to succeed in such a time scale or just produce a drive for brush-less that shows signs of working on the bench?
I don't have a circuit which doesn't use a microprocessor, and frankly no-one in their right mind would propose designing one from scratch.
It's rather like the boss of Ford deciding that the unchanged original design features of the model T should be put into mass production in the latest model, and introduced to the world in the creationist museum with Adam driving it with his pet Dinosaur, It doesn't make sense!
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Re: Quadcopter with zero microprocessor :D

Postby ayadabd000 » Tue May 28, 2013 9:57 am

Again I know the difficulties of the task, but no alternatives. I dont know the real intentions of my professor, so all I can do is to give it my best..we are group of 10 and deadline could be extended to four weeks if we really showed real progress.. Anyway, thanks a lot for your help and your time:)
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Re: Quadcopter with zero microprocessor :D

Postby cynr100 » Tue May 28, 2013 9:09 pm

Hmmmmmm..................4 brushed motors for flight with one on/off switch, 1 brushed motor spinning a weight wheel in the vertical plane and 1 brushed motor spinning a weight wheel in the horizontal plane.
Spin the gyro wheels up first, when stabilised (or max speed) turn on the lift motors and stand back. Is there a requirement for inflight control or flight duration. If not this should get you through, the biggest problem would be calculating optimum wheel speed, all up weight and lift required. Is that what he is after?
Just some quick input, only just caught this thread...............off to work, bummer.
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Re: Quadcopter with zero microprocessor :D

Postby BillGriffiths100 » Wed May 29, 2013 1:07 pm

1 brushed motor spinning a weight wheel in the vertical plane and 1 brushed motor spinning a weight wheel in the horizontal plane.

I think you could get weird procession effects with that but you reminded me that there are chips with analogue outputs that could be used for motor control such as:
https://www.google.co.uk/url?sa=t&rct=j ... R2lYDcmD4g
Download it when you get to it otherwise it takes forever to show the data.
Using analogue circuitry it should be possible to control the motors.
ayadabd000, your professor thinks in analogue that's what he's after.
Good old analogue!
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Re: Quadcopter with zero microprocessor :D

Postby ayadabd000 » Wed May 29, 2013 2:05 pm

Yeah I think that's what he's after! I am starting to have some hope that this is actually possible! :)
I am now searching for good brushed motors. Any advice of what to look for? How can I know that a motor will have a good thrust to lift the quad?
Thank you all for all the help!
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Re: Quadcopter with zero microprocessor :D

Postby BillGriffiths100 » Wed May 29, 2013 4:02 pm

No I'm sorry I can't recommend anything, these type of motors seem to have disappeared from the market but to drive the larger props you will require for lift you will almost certainly have to gear the motor down about 3 or 4 to 1 and run it at high rpm to get the power out of it.
Probably 450 type can motors will be OK if you can find them buy spares because you will probably burn them out if they use brass brushes try to get ones with carbon brushes if possible they will last longer.
All I can find these days are 550 types
http://www3.towerhobbies.com/cgi-bin/wt ... LXDWY0&P=7
http://www3.towerhobbies.com/cgi-bin/wt ... XWHX0&P=ML
But even those are out of stock
You will have to scale your craft according to the motors you can buy.
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Re: Quadcopter with zero microprocessor :D

Postby cynr100 » Thu May 30, 2013 1:05 am

This might have some useful info for you on analogue gyros

http://www.rchelicopterfun.com/rc-helicopter-gyro.html
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