Thread Tools
Nov 09, 2010, 04:11 AM
That tree again!!!!
thanhTran's Avatar
Thread OP
Build Log

Building a palm size quad-copter & Introducing a new simple flight controller

Hello all,

After some time flying with a 12"-arm quad-copters, I want to build a small one to fly in the office, and I also want to see how it feels to see a small quad fly.

1. 10" motor to motor configuration:

Video here

2. 6.5" motor to motor (same as the 10" but with cut down arm length. It uses 4 brushless ESCs, 4 brushless motors, external receiver - currently flying with built-in receiver):

Video here

3. 4" motor to motor (brushed motors, counter rotating props, built-in receiver, Wii MP gyro board, no ESC):

Video here

4. 3" motor to motor (same set up as the 4" above)

Video here

5. 3.6" motor to motor (brushless version) intended to have longer arm for real-estate reason.


6. iphone as the TX setup:

Part list:

6" or bigger quad:
* 4 x Hextronix 5g brushless motors
* 4 x 6A Turnigy Plush ESC's
* 4 GWS EP 4025 props. These props are just regular CCW props, I will have to tilt 2 motors front and back for counter rotating purpose.
* Rhino 460mAh 2-cell Lipo battery
* Update: HobbyKing now carry 40x25 counter rotating props:

4" or smaller quad:
* Walkera UFO#8 motor set: or here:, or:
* Counter rotating props: (about 4cm long)
EDIT: Mike gave us another source for the props:

* 350mAh 1-cell LIPO battery:
* Simple flight controller: TI wireless dev kit

The software:

* Gyros: Using a Wii Motion Plus gyro board (original Nitendo version - the clone version is now a digital gyro and won't work)

Or a home made ST gyro board using (LPY550AL and LPR550AL):

* Frame: made of thin & light aluminum tubes I bought at a local hobby store. Its size is 3/16 x 3/16" and is 12" long. The 4" quad version is using some small 1/16" CF rods.

* Receiver: There are two options:
1. Any external RX that match your TX would work, or
2. Using the built-in radio chip (CC2500) of the TI Wireless dev kit, and use make an RF module to work with your TX. See build thread for more info.

* Wii Motion plus board: $11
* Main controller: $25 (since we are using only one target board of the wireless dev kit)
* 4 motors: $28
* 4 ESC's: $32
* battery: $5

* RX & TX are not counted as everyone of us should have a set, but any TX & RX should work. I've tested my controller code with Spektrum DSM1, FrSky.

* An option of using no external receiver (thanks to the TI's MSP430-2500RF kit) is also utilized. In that case, the cost and weight of the quad is even reduced more.


1. Using your own receiver and brushless ESC:

2. Using built-in RF radio of the TI's EZ2500RF kit for receiving controls from another TI EZ2500RF kit (save weights) and brushed motors:

3. Using built-in RF radio of the TI wireless dev kit, and brushless ESC: schematic is similar to the brushed motors above, but just remove 4 FETs and connects the MCU's pins to the brushless speed controller.

If built-in radio of the MCU board (MSP430 EZ2500RF board) is used, then an adapter to the RC radio using PPM stream from the buddy port or from the PPM pin of the RF module (like HiTec Eclipse or Futaba module) is needed. The schematic for such device is this:

Last edited by thanhTran; Oct 03, 2012 at 05:33 AM.
Sign up now
to remove ads between posts
Nov 09, 2010, 04:14 AM
That tree again!!!!
thanhTran's Avatar
Thread OP
Build the frame:
I cut the aluminum tubes down to 10" long. I guess I can cut it shorter, but let's see how this go. One arm is now cut by half. The two half's are joined together with the other uncut arm to form a cross. They are then hot glued and screwed to 2 pieces of hobby ply wood (1/16" thick)

And the finished frame:

Drill holes that fit the motor mount & cut the two arms that would be the front and the back of the quads. I cut it at about 2" from the end of the arm.

The cut is necessary so that I can tilt the front and back motors.

Tilting mechanism
I found some aluminum tubes (also at local hobby shop). The stock number is: #3060. It has its outer diameter being 3/16" which is almost a snug fit to the aluminum tubes. So I cut 2 pieces of this round tube; Each is about 1" long.

I use a heat gun to heat both the tubes and then I put some hot glue into the tubes, and then the round tubes are pressed inside. After that the 2" square tubes are also pressed in.

I tilt both of them about 8 degrees. The front arm tilts to the left (look from the back motor). The back arm tilts to the right.

The hot glue can be then melt with a heat gun so that I can twist to adjust the tilting angle.

Install motors & ESC's

4 ESCs

Power distribution
I cut two pieces of copper clad PCB. CA glued them to the wood. And then solder the ESC's battery wires onto these coppers:

schematic of the controller, RX, and motors (actually it just a schematic of how to connect the EZ2500RF board to the motors, gyros, and receiver)

Connect all electronic parts together
Here are the pads of the connections that we need on the back of the controller board:

Solder 3 soft wires to those pads. I use soft 28awg wires for these

Install the gyro board
Stick two pieces of 4mm foam tapes on to the top of the frame plate:

Stick the gyro board on those foams:

Two power wires (5v) for this gyro board is taken from the BEC of one of the ESC's (the red & black wires on top of the photo). All ESC's wires are cut and just leave the white wires (signal wires).
The gyro board has a 3v regulator which provides 3v for the gyros and for the RF2500T target board (the red board). This wire is one of the white wire on top of the left gyro chip. Solders 3 wires to the outputs of 3 gyros: roll (orange), pitch (brown) & yaw (red). These wires will connect to the red board.

install RX
Add two spacers (which were part of the frame tubes which were cut earlier), and stick the RX on top of them.

Stick the controller board on top and connect all wires to it:
Last edited by thanhTran; Dec 29, 2010 at 03:18 PM.
Nov 09, 2010, 04:15 AM
That tree again!!!!
thanhTran's Avatar
Thread OP

Load the software to the controller and program the settings

Plug the programmer (which comes with the RF development kit as well) to the PC and to the target board (the red board)

Click the button to program the code and to load to the code to the board from Code Composure Studio (a development tool from TI that comes with the kit. It allows to write code, debug & run the code, and also write the code to the flash memory of the controller).

The console (which is connected to the controller board (the red board) via the programming dongle is now showing that the copter is alive!

This console is the main interface to change the settings of the quad-copters. The main settings we need for the flight are the those that set the direction of the gyro so that the software knows which way to correct the copter depends on the reading it sees from the gyros. It also shows readings of all the plugged channels (aileron, elevator, throttle, rudder, gyro gain) the gyro status, the min/max reading of gyros, as well as the min and max signals sent to the motors.

Last edited by thanhTran; Nov 10, 2010 at 03:26 AM.
Nov 09, 2010, 02:10 PM
Registered User
that just the stuff dude !!!
Nov 09, 2010, 02:45 PM
Registered User
I have a question about the tilting of your motors.

I have heard You can achieve the same Yaw authority by using normal props tilted at 5degrees to 10 degrees to the right as you look at the rotor but you will lose overall efficiency.

I do not see this done very offen.

How much overall efficiency is lost?

I find that finding the small counter props is not easy.

What about motor direction ? still the same?
Last edited by witespy; Nov 09, 2010 at 03:59 PM.
Nov 09, 2010, 04:55 PM
That tree again!!!!
thanhTran's Avatar
Thread OP
Hi Witespy

I agree that it's so hard or too expensive to get small CW props.

Yes, all 4 motors running same direction (CCW). For sure we loose some lift with tilting props, but that tilting is done the same way in tri-copter too. I've not done any comparison of the same quad with and without CW props to see how much flight time we loose. Maybe someone already has some numbers.

Nov 10, 2010, 03:27 AM
That tree again!!!!
thanhTran's Avatar
Thread OP
The whole quad without battery weights: 88g. Battery (460mAh) weights another 30g. So RTF weight is about 118g.

Newer edition (as of 11/18/2010)
Last edited by thanhTran; Nov 21, 2010 at 08:48 AM. Reason: update photo
Nov 10, 2010, 04:02 AM
Registered User
Video please!
Nov 10, 2010, 04:44 AM
That tree again!!!!
thanhTran's Avatar
Thread OP
Video added

Palmsize quad copter indoor (MSP430 based quadcopter) (1 min 46 sec)

I was trying to do a small circle flight in the living room, but it was too fast for me, and thus it almost hit the couch. It hovers pretty stable though. I think to fly in a living room, I need to build a smaller one so that it flies slower.
Nov 10, 2010, 05:43 AM
Registered User
knuckles904's Avatar
Great build and great video. Interesting choice for microC. Are you using the wireless capability for anything? Do you know if the target boards are compatible with the chronos programmable wireless watch dev kits? Might make for an interesting mashup

edit: wow, whats even more impressive is that you actually commented your code well
Last edited by knuckles904; Nov 10, 2010 at 05:49 AM. Reason: more to add
Nov 10, 2010, 03:54 PM
That tree again!!!!
thanhTran's Avatar
Thread OP
Originally Posted by knuckles904
... Are you using the wireless capability for anything? Do you know if the target boards are compatible with the chronos programmable wireless watch dev kits? ...
Hi Knuckles

Thanks for looking at the project and codes

I'm really glad to see someone knowing the chip and the development platform.

No I'm not using the wireless portion at this time. But I reserve the wireless potion for several possibilities in mind:

1. Using it as a receiver so that I can eliminate the 8g receiver (the weight of the 2500T board is only around 3g). This should be beneficial for smaller & lighter quad/tricopter.

2. Using it for some remote loggings and settings. Currently I can plug a bluetooth dongle and can do some live monitoring and settings from a near by laptop while the quad is flying.

Yes, the Chronos watch programming dongle works with this set up. The programming dongle in this photo is the one from the Chronos kit. If you already have the Chronos, you just need to buy the ez430-2500T board alone for $20.

I've thought about using the accelerometer and the air pressure sensor in the Chronos watch for a full blown quad so that it can auto level and keep its altitude. I've also thought about using the Chronos as a TX (in which case I have to change the controller board to a 915Mhz instead of 2.4Ghz one) and controlling the quad by tilting the watch and its button. Yeah more works needed.


Nov 10, 2010, 05:33 PM
Registered User
PeteSchug's Avatar

The video looks fantastic.

I just found this thread and browsed it very fast. Time to go back for a nice slow look!

Nov 10, 2010, 07:25 PM
That tree again!!!!
thanhTran's Avatar
Thread OP
Thanks Pete!
I just realized some pictures are missing here. They showed up when I viewed from the PC I posted the thread but not on a different PC. Will update them again.

I'm thinking about shrinking the size of the quad even more. Maybe I need to use brushed ESC. Any suggestion, anyone?


Nov 10, 2010, 08:11 PM
Z06 Tony's Avatar
Originally Posted by thanhTran
Thanks Pete!
I just realized some pictures are missing here. They showed up when I viewed from the PC I posted the thread but not on a different PC. Will update them again.

I'm thinking about shrinking the size of the quad even more. Maybe I need to use brushed ESC. Any suggestion, anyone?


Nice quad and looks very stable.
Here is an 11" across I built->

Here is an 8 motor same electronics etc..->
I also just did one that is only 9" across and very stable but did not do a build log for that one.
Nov 10, 2010, 08:45 PM
That tree again!!!!
thanhTran's Avatar
Thread OP
That's cool Tony! Thanks for sharing. I like the octo one. I wasn't so clear about its set up. How did you connect 8 motors to the Gaui controller? Were you just Y connecting the input of 2 ESCs together?

I think I can easily cut away 1.5" on each of the arms, and that will make a 6" across quad or 3" for each arm (motor to motor distant will be 5"). The prop currently is 4x2.5. Maybe I can use a smaller prop for slower flying (I want to do real flying in the living room, not just hover from place to place)

Quick Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Parts for tri-copter or quad-copter BloomingtonFPV Aircraft - Electric - Power Systems (FS/W) 4 Aug 20, 2010 08:20 AM
Discussion Tri-Copter and Quad-copter Rotations CaptainRedmuff Multirotor Drone Talk 6 Jul 01, 2010 10:52 AM
Build Log STM8s Quad-copter "Quad-radic" Edftakeoff Multirotor Drone Talk 4 May 17, 2010 03:09 AM
For Sale tri-copter or quad-copter blades HyperHelis Aircraft - Electric - Helis (FS/W) 0 Sep 17, 2009 04:22 PM
Question Tri/hexa-copter or Quad/Octa-copter and Spartan AP2000i or Helicommand Arthur P. VTOLs 2 May 20, 2007 03:02 PM