Indoor fun with a tiny ArduCopter quadcopter

Do you have an Ardupilot Mega and shield and want some fun for little money? check this tiny quad... my last drone in family...

Some specs:
- Size : 26.5cm (10.4 inches) from motor to motor
- Motors : 18-11 200kv 10 gram motors
- Props : 4x2.5 (standard CCW props)
- ESCs : Turnigy 6A
- Battery : 3S610 (or 3S800)
- Sonar : Maxbotics LV-EZ0 [optional]

The nice part about this frame is that it use standard kite parts, so it´s very easy to construct and it´s perfect for some radical tests.
Itried to find a bit different design that also make the quad less simmetrical (it´s very easy to loss the orientation with a quad) and I wanted to do as small as posible to flight indoors...
At this size and weight it´s very safe and robust also. The props use prop savers and this help a lot in crashes...
I am not very good writing... so I took a lot of photos during the build phase and I created a build log:

This code supports a sonar for altitude hold and also has a battery alarm (2 alarms).
Thisquad works with ArduCopter code, but because how main board is mounted, actual code doesn´t work. This is the code that I used with this quad :
(as zip format: )
note that this will be integrated on main Arducopter code. Now is temporarily in a branch.
ThePID gains are different than in standard ArduCopter, so you need to Initialize EEPROM on Configurator or put this ones manually:
-Stable mode: P : 4.8 ; I : 0.12 ; P_rate (D in configurator) : 0.4 ; Yaw : (4.5 ,0.15 ,2.8 )
-Acrobatic mode : P : 0.75 ; I : 0.1 ; D : 0 ; Yaw : (2.4 ,0.2 ,0 )

OK, but was all so perfect like in the video? I don´t believe that...
Yes, you are right, but fortunately this design is very crash resistance... and this part is also fun...

After all this battles I only needed a few drops of ciano in the crash with the lamppost :-)

What´s the real size?

On center, standard arducopter frame, on left, old ArduIMU quadcopter part III, on right-top this project.

And what about the automatic aerobatics on video?
I am starting to test a new function to do automatic aerobatics (Automatic Aerobatic Procedure). The idea is that you enable this function with a switch in the Tx to make an automatic predefined aerobatic and then automatically recover to a stable mode.
Thisis actually a proof of concept but works very nice. One limit here is the maximun rate of the gyros, in our case 500deg/s. If we exceed this, the IMU get confused...
An interesting point to note is that the IMU doesn´t loose the orientation in this hard movements...
Thestory is that I have never feel too much confidence doing flips manually with quads. Then I start thinking that with an automatic code we can get a precise timing and controled movement so maybe this could help to do better aerobatics. I started testing this function outdoor, on an open field but I was improving the code and got more tightly maneuvers, so tight, that I ended up doing flips with a quad inside my room!!!

Here is the code I was testing : (AAP function:
AAP.txt )
I implemented this functionality as a state machine where there are three kind of states:
- fixed commands for a limited period of time. (example : Apply a throttle command)
- fixed commands until we reach some IMU state (example : roll until we reach a certain angle)
- And a mix between this categories and a control (example : Throttle command + stable mode on roll, pitch, yaw)
There are many things to test and improve here but the basic concept works very nice...

If I can get a bit of help from a friend, I will probably made a carbon fuselage for this prototype...

Enjoy this “Science & Fun” mix...

Jose Julio.
Arducopter Team
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  • Jose, do we have to make any change in the SJ1 solder jumper (or anyother) in order to feed the Ardupilot with a 3S lipo?
  • Developer

    @Michael, nice work....

    Yes, it can carry a small payload... I´d prefer to use the 4" prop becuase motors run cooler but if you want to carry a cam you probably need the 5"...


  • Developer

    @Tero, it seems that you lost one motor on the landing... anyway it starts to fly...

    @Oscar, I have not used connectors for the motors, they are directly soldered to the ESCs and I used the wires that comes from the ESCs (no more wires). Connector from ESC to battery are mini deans.

    The ESC´s are not 3S rated because the 5v regulator is very "soft" but we are using the regulator on the APM board so is not a problem for us... Motors are OK also in 3S with this prop (no broken motor yet...) they finish only a bit warm...


  • Thanks to Jose I had the confidence to move forward on my own tiny quad. This one is flying a KKMulticopter Brain. Same ESCs, motors and props as Jose's. It runs beautifully on a 3S battery and can payload a GoPro HD pretty easily (that's with the 5" props, I haven't tried the GoPro with the 4" props, but the quad flies great with either set) So far it's proven (pretty) easy to fly and just about indestructible.


    I agree with Kenta on the bullet connectors, I had several infuriating, expensive crashes due to bullet connectors coming loose. Motors turning off mid flight with cameras on board. Since I stopped using them, I haven't had any such failures.


    I'm planning on further refining my variation of the tiny quad design later on, I'll let you guys know. Here are some pics!



  • T3
    What about the motors though? I would be just as concerned about that as with the ESC's. The specs suggest 2S but it doesn't ever say 3S is okay. I suppose Jose has been using it on 3S so it's not a big deal but I would be curious to hear if it has been an issue.
    As to the bullet connectors, I would solder the ESC straight to the motor. I've read a lot of posts about people having issues with motors blipping and causing problems with the bullets but all the issues went away when they direct soldered everything together.
  • Those Esc are not guaranted to work with 3S, but you can put any esc that does. I´m going with 12A Esc Mistery BluSeries.


  • T3
    How long do those motors last? I noticed you use a 3S LiPo but the motors and ESC's are really only rated for 2S. This quad has really gotten me interested in putting one together instead of a tricopter.
  • Hi Jose,

    What size of bullet connector have you used on those motors? 3.5mm?? and the wire? 18awg?? i´m finishing my order and i want to be sure.



  • After couple of days hard trial and error tuning:


  • Developer

    Hi Ralph, pizcolq,

    You can use NG code if you change the IMU orientation (as Jani explains) you need to put the IMU aligned from Front to Back arms, but in actual NG code, the ultrasonic sensor is not yet fully implemented, so I´d recommend that for this project start with the post code and then change to NG if you like.

    Also the original code has the PID gains adjusted to this platform...

    Merry Christmas to all!!


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