Multiwii PRO with GPS having a gitch, Need help

[docbrian]

Hello all, a real newbie here, but learning. My son (the Arduino wiz) and I have build our first Quad X copter. All parts were purchased from HK on line. We have the Mulitwii PRO board with GPS, the SK450 frame, F-30a HK ESC's Flashed with SimonK, Turnigy 2830-11 1000Kv motors with 10x4.7 props. Running off a 2S 4000mAh Turnigy battery. The TX/RX is the Turnigy 9x.

After a few nerve racking attempts for liftoff, Dad (me) took controls and was a bit more aggressive with the throttle. Had it in the air for like 2-3 seconds at about 1 meter then lost control and down it went, bending 1 prop, but nothing broke. Then after reading some more online, realized that we hadn't calibrated the ESC's. So we calibrated each one individually. Still a problem. Then we calibrated all together using the Multiwii board. We have Multiwii 2.2 uploaded and uncommented the ESC Cannot Fly, then uploaded, had beeps and flashes, but the motors did not spin up (I thought they were supposed to). Recommented that same command line.

So what we are finding is that the Left rear motor (D6) is not spinning up as fast as the other. When we connect the Multiwii Config program with the Quad powered up and motors armed. We see the throttle respond from 1050 to 1880. We also see all other inputs respond with similar values. The Multiwii output to the motors are not the same. 3 out of the 4 motors, at full throttle will be around 1800. The 4th (D6) will only go as high as 1400 or so. We think we have calibrated the ACC and Gyro from the config program and saved. When I pick up the quad the motor speeds adjust correctly and I can feel the adjustments too when I have the props on and holding it over my head. All seems to respond correctly, except that one motor is slow. We have only 1 ESC red wire connected to the multiwii. We have even added a 3600uf 6.3v capacitor to the multiwii to help with any possible brownouts.

The reason we think it is something to do with the configuration, and programming is that when we swap the motor and esc with a different one on the quad, the motor and esc behaves as the one it replaced. Still having the D6 motor and esc being slow compared to the others, not matter which motor and esc is connected to D6.

[scrat]

Hello.

First of all. Adjust stick travel from 1000 to 2000 if you can with original TGY9X Tx. If you can't then flash Tx with er9x or openTx firmware. Set in config.h Minthrottle to 1064, Maxthrottle to 1950 and Mincommand to 1000. Then uncomment ESC CALIB CANNOT FLY and calibrate esc's. Then comment it out and load FW on FC and try.

[tovrin]

BTW, the spinup during the ESC calib is only if you are using li-po while uploading the code and dont power it completely off before resetting the arduino. done correctly it should not spin up.


now, to address your problem, definitely follow Scrat's advice, but also make sure you have all accessories disabled in GUI before first flight, calibrate your ACC using the GUI (not using it yet anyway but it doesn't hurt to calibrate it)

and then try to gently get it in the air above some grass, the motor speeds when its being held or on the ground are not as accurate or useful to you until its in the air adjusting its flight. look through the forum and you will see post after post from people who haven't gotten their copter off the ground because they see one motor not spinning as fast and stop trying, but once its in the air you will truly know if you have a problem, so keep it close to ground and above something soft.