First build: mini quad

[alaala73]

Hi

I'd like to build a small quadcopter without any (or, better said, as little as possible) pre-build parts: I'd like to program by myself one/some microcontroller/s to control the motors and the sensors I'm going to use and I should be able to do it, but I actually don't now how to make all that fly.
The quadcopter doesn't need to carry any load other than some sensors (I estimate them to weigh 5-15 g all togheter), but it should be quite stable and also a bit "agile" (that is, it doesn't need to do any acrobatics, but it can't be a flying hippopotamus), and to be able to fly as long as possible whitout recharging the battery.

I already have 4 little brushed motors like these ones (I don't konw if they can do the job, I bought them for a non-flying project): http://www.hobbyking.com/hobbyking/store/__86504__Mini_Quad_Brushed_Motor_8_5x20mm_4_Pack_.html whit these propellers: http://www.hobbyking.com/hobbyking/store/__86505__60mm_Propeller_Quad_Set_4_pcs_.html and no idea about how powerful they are, how much voltage and current should I apply to them and so on. I also have no idea about what kind of battery I should use.

Can anyone give me some piece of advice about motors, propellers, batteries and so on?

Thanks
ala

 

[RENOV8R]

Hi

I'd like to build a small quadcopter without any (or, better said, as little as possible) pre-build parts: I'd like to program by myself one/some microcontroller/s to control the motors and the sensors I'm going to use and I should be able to do it, but I actually don't now how to make all that fly.
The quadcopter doesn't need to carry any load other than some sensors (I estimate them to weigh 5-15 g all togheter), but it should be quite stable and also a bit "agile" (that is, it doesn't need to do any acrobatics, but it can't be a flying hippopotamus), and to be able to fly as long as possible whitout recharging the battery.

I already have 4 little brushed motors like these ones (I don't konw if they can do the job, I bought them for a non-flying project): http://www.hobbyking.com/hobbyking/store/__86504__Mini_Quad_Brushed_Motor_8_5x20mm_4_Pack_.html whit these propellers: http://www.hobbyking.com/hobbyking/store/__86505__60mm_Propeller_Quad_Set_4_pcs_.html and no idea about how powerful they are, how much voltage and current should I apply to them and so on. I also have no idea about what kind of battery I should use.

Can anyone give me some piece of advice about motors, propellers, batteries and so on?

Thanks
ala

Those motors and props are well matched and would work well on a quad frame in the 100mm-150mm range with a 1 cell lipo (lithium polymer) battery in the 650 mah range. There are gazillions of frames out there to choose from, but in this size, you'll get a whole lot of agility and not a lot of stability. Quads of this type have a flight time of about 7 or 8 minutes.

 

[alaala73]

Thank you, but I still have some questions:
1) what is a 1 cell lipo? is it 3.7v?
2) I just looked for such a battery around the web, and I found some specifications om thrm that I don't understand: what means 10C or 20C? and is the mAh value the total charge the battery can store or something like the current it can safely output?
3) how much current do my motors with my propellers (see links in the first message) need to work at their maximum speed (I don't need a precise value, only some vague idea)
4) how much can such a quadcopter whit those motors and propellers weigh in total? how does weight affects agility and stability?

 

[alaala73]

other question: has an itg3205 triple axis gyroscope enough resolution to control the flight of a small quadcopter?

 

[RENOV8R]

Thank you, but I still have some questions:
1) what is a 1 cell lipo? is it 3.7v?
2) I just looked for such a battery around the web, and I found some specifications om thrm that I don't understand: what means 10C or 20C? and is the mAh value the total charge the battery can store or something like the current it can safely output?
3) how much current do my motors with my propellers (see links in the first message) need to work at their maximum speed (I don't need a precise value, only some vague idea)
4) how much can such a quadcopter whit those motors and propellers weigh in total? how does weight affects agility and stability?

1) Yes, a 1 cell lipo = 3.7 volts
2) C in C rating stands for Capacity. 10C = 10X the maximum discharge rate of the capacity. So if you have 10C 2000 mah (2 amps) C rating X amps = maximum discharge rate. So it would have a discharge rate of 20 amps.
In a nutshell, a higher C rating will give you more power, and a higher mah rating will give you longer flight times.
3) In general, your motors and props would work very well in a quad with a fame size of around 130mm
4) I have a 130mm frame ordered made by Micro Motor Warehouse that you may be interested in called the Reggae Shark. Made of plastic instead of carbon fiber so it may be a good starter for you as it is more durable, and believe me you will crash. A lot. We all do hahaha. Here's a video Michael Grabner posted a while ago on the Shark, it should answer some of your questions

 

[alaala73]

So, basically, if I put my 4 motors in a frame like the one in the video and I connect them in parallel to a 3.7 V battery they will fly? (and I suppose immediately crash, that will be my next problem to solve)
And, by the way, another question: has an itg3205 triple axis gyroscope enough resolution to control the flight of such a quadcopter with an acceptable stability?

 

[RENOV8R]

So, basically, if I put my 4 motors in a frame like the one in the video and I connect them in parallel to a 3.7 V battery they will fly? (and I suppose immediately crash, that will be my next problem to solve)
And, by the way, another question: has an itg3205 triple axis gyroscope enough resolution to control the flight of such a quadcopter with an acceptable stability?

No it won't and no it won't

 

[alaala73]

No it won't and no it won't

What have I to do, then? Better explained my idea was to connect each - wire of the motors to GND and each + to VCC (obviously, if it works, I will add a controller to regulate each motor's speed), if it's not true, what have I to make with a 3.7v battery and 4 motors?
And what sensor can I use? (I thought that the itg3205 wasn't an adequate sensor, but I bought it some time ago and don't use it any more, so I asked...)