Hey!
There is a problem that I'm facing with my quadrotor. It just refuses to lift-off!! Tried a lot of things and suggestions, but no success till now!

Im using..
Hextronic DT700 motors
Turnigy Plush 30A ESC
Turnigy 2200mah 25C LiPo
Sparkfun 9 dof IMU

Someone please help!?

Sorry forgot to mention! Im using 10x4.5 counter-rotating propellers from RCDhamaka...
12x4.5 ordered today, would be arriving here soon!

And the total weight inclusive of the battery is around 1250-1300 gms!

If you received a FTDI basic breakout (A programmer for the 9dof FC), then, plug it into your Flight controller, buy a mini-USB cable and connect it to your PC. Download and install the FTDI drivers. Download and install the arduino software onto your PC. (v1.0 is the latest, but I like v0.23)

You should see several files that are pre-flashed on the board (like a firmware). I expect to see some .pde files. Open them. (Simply double-click and windows asks you to select a program and select "arduino" from the list) In any ONE file, you see something like MAXTHROTTLE (or an equivalent verbatim) defined. (For eg, in MultiWii, it's MAXTHROTTLE). Set it to the MAXIMUM possible value. (I guess it's 2000). This "MAXTHROTTLE" value is the throttle input given to the ESCs when Maximum throttle is received by the Flight controller from the Rx.
This increases the throttle given to ESCs and the thrust goes up!

BTW, your quad's weight is on the higher side. Sure, it falls in the acceptable range, but reduce it. My MultiWii quad also uses dt700s and it weighs 1190g. After lots of trouble, it's now hovering! I am now switching to a smaller LiPo and simplifying the frame so as to reach my target of 1000g.

Also, download a GUI to modify settings of your FC. I searched and found them here. (download the 1st file on the list) http://code.google.com/p/sf9domahrs/downloads/list

Also check the sensor-axis orientations. They might be reversed. You'll have more trouble then! Read more on programming the Flight controller.

Reduce the weight and I guess all the hardware setup is fine! (let seniors comment on that) It has to fly for sure. (again, I am a beginner, too)
PS: Some points might be specific to MultiWii, sorry for that, but I am sure there's an equivalent version for your FC too!

Vineet

Jaspreet, may i ask how have you connected your ESCs to the controller board ?? because the output the AHRS code provides is just the euler angles (Roll, Pitch, Yaw) on the serial port.

You require a secondary micro-controller that understands the Radio inputs (PWM from Receiver) and then using the AHRS data from 9 DoF on Serial port and implementing a PI or PID control feedback loop and finally send instructions(PWM) to the ESC.

Hope you were able to follow all the mumbo jumbo 

Hey Fellas,

Right now I am struck with a problem building my quadrotor..
My Quadrotor configurations are Arduino UNO+ZigBee+9DOF IMU
The problem is such that,
Arduino UNO has got only single Serial UART and I have two ZigBee and 9DOF both are giving me outputs in serial. So, how to overcome this problem..? Is there anything logically I have to resolve or are there hardwares available that allows two UARTs connections with single microcontroller..??

Guyz, please do reply.!!

Regards,
 Bhaumik

Bhaumik, what you can do is connect your 9DOF IMU to the hardware serial pins (Pin 0 and Pin 1).

And then for the Zigbee you can use a software serial port. There's an included library for this in most of the recent ARDUINO versions.

There's plenty of material available for the software serial library. I'll still give you a basic example for your understanding.


Another thing that you need to informed about is that software serial library is memory intensive and also slows down your loop rate. This means that the frequency at which a loop of your code gets executed would be reduced. Again, this is not something that you should be overly concerned about at this stage.

You would also need to disconnect your IMU from pins 0 and 1 when you upload a code or communicate serially with the computer.

Thanx Jaspreet,
Software Serial is a good alternative.
Recently I tried that library and successfully communicated between two ZigBee. The read operation on receiver side went very well. But, not happy with the write operation from receiver arduino. Coz it is getting some delay in writing the data back from the arduino.

And another thing is that I am not able to specify baud rate of ZigBee less than 9600. So, I am still using baudrate 9600 on Softwarely declared serial pins...

Regards,
Bhaumik Khamar