Mikrokopter Fresh build, need help please

[llamatrails]

I am converting a working quad to use a MK FC v2.1ME with an AbuseMark i2c to PWM converter. No Navi-Ctrl, GPS, or MK3Mag boards.

The quad has been flying fine with a HoverflyPro FC.

KDA 20-22L motors
Turnigy Plush 30A ESC
Precision I2C to PWM Converter for Standard ESC [ST] w/ 2011/04/21 firmware installed yesterday, no problems with the procedure
3S 4000mAh LiPo

The MK is running freshly loaded 0.84a firmware, configured for a Quad-X Beginner. All settings are default, other than disabling the GPS and enabling the Altitude Control. The i2c board is wired with the molex connector on the FC, I cut the molex cable and crimped in a 3pin servo connector to connect to the i2c board.

The problem is that the motors do not all spin at the same speed at idle, when I enable/start the motors. I can see #3 is spinning slower, and #2 may not even start. If I increase the throttle, they will all spin up, but #2 will stop before I reach liftoff. Obviously, I have not actually tried to lift off.

I originally had the ESC timing at low, and changed it to medium to match what I have found in the announcement/support thread for the i2c board. The problem still exists. There is also some chirping of the ESCs.

On the MK when in MKTools, I can run the motor tests and all 4 will run. I can advance the throttle on each individually, none cut out as the throttle is increased.

I did notice that the LCD in MKTools only shows 1 BL-Ctrl instead of 4. Is this correct?

Anyone have any insight as to why the motors aren't spinning up at the same time/speed and staying on?

 

[RTRyder]

Go into the flight control board 'Settings' in MKtool and open the Misc tab, set the Min Gas setting to 12 or 14 if 12 isn't quite enough and that will solve your problem.

Oh, and make sure to do the ESC throttle calibration on the I2C converter too, the combination of that and the min gas setting got it all working right for me.

With the converter you will only see 1 attached BL controller in Mk tool, there are some stats it reports back to the flight controller that are bogus as well, done just because the board expects to see a response coming back.

Ken

 

[llamatrails]

Thanks Ken, that got me over that hump. All the motors now start and stop as expected. I did the ESC throttle calibration after I updated the firmware.

Next problem - I am in Beginner mode, #3, and the throttle is out of whack.

It will take off, shoot up to about 20-30 feet, and as I drop the throttle, it will then come straight down, slam into the ground, and bounce back into the air to repeat until I can get it to stay down.

Actually, I am way impressed with the fact that it stays perfectly level the entire time with no drift! If this was the HF, it would have drifted, flipped, and trashed itself on the first drop.

It is acting like there is a huge amount of expo on the throttle. I have to run up to almost mid stick to get liftoff, then it shoots up and I have to pull the stick all the way down to get it to stop climbing, then use full throttle to get it to go back up when trying to prevent it from grounding. I did get it to hover at about 30' but when I drop the stick a fraction it pancakes into the ground and bounces back up.

My throttle endpoints are +100/-100 on a JR10X Heli, no expo is configured. Throttle curve is linear from 0-100, pitch curve is flat on 0. All of this works fine for the HF, I don't use channel 6.

I am using a Spektrum satellite wired directly onto the FC, no diversity board at this time. Channel 5 is my POTI1. I have MinGas at 17 and MaxGas at 230 (default).

Any ideas? What to look at/change?

Edit:
I just noticed that my Gas value in MKTools in the left panel is 120-489 while connected. Is this normal?

 

[llamatrails]

While waiting on dinner, I realized that while I had set the subtrims for K2-4, I hadn't done anything for K1 or the other K numbers. Googled and found a video on setting the transmitter, and all is well now. I believe my vertical zooming was because my gear channel also needed to be reversed, the altitude hold was enabled when it shouldn't have been.

Had a good flight, and now just need to get more used to the MK way.

This forum is better than paying a shrink to talk things out.

 

[Crash]

This forum is better than paying a shrink to talk things out.

How long have you felt that way?

//Shrink Joke.

Spend some time reading the MK wiki pages. (Yes we know it's a huge PITA especially when you use a translator on the German pages.)

They do tend to fly well. And they can also fly away well if not setup properly.

 

[llamatrails]

I have perused the wiki, the 'other' forum zillion pages, and am more confused than enlightened.

The confusion is now the transmitter, K1-5 values, and ACC calibration.

Got the transmitter to show -125/+125 for K1-5 when trims and subtrims are at 0 in the transmitter. Now, since K1-5 don't show zero for center, I use the subtrim to zero K1-5, then level the arms/motors and calibrate the ACC. Good to here.

The confusion is that when I adjust the subtrims to show 0, the K endpoints are now shifted from -125/+125. Is this a problem or normal?

If I try to mess with the endpoints the center moves. I understand why we need the center to be at 0 for a level baseline. Fine, so should I ignore the shift of the endpoints since we got the ACC calibrated?

 

[Mactadpole]

I have perused the wiki, the 'other' forum zillion pages, and am more confused than enlightened.

The confusion is now the transmitter, K1-5 values, and ACC calibration.

Got the transmitter to show -125/+125 for K1-5 when trims and subtrims are at 0 in the transmitter. Now, since K1-5 don't show zero for center, I use the subtrim to zero K1-5, then level the arms/motors and calibrate the ACC. Good to here.

The confusion is that when I adjust the subtrims to show 0, the K endpoints are now shifted from -125/+125. Is this a problem or normal?

If I try to mess with the endpoints the center moves. I understand why we need the center to be at 0 for a level baseline. Fine, so should I ignore the shift of the endpoints since we got the ACC calibrated?

Rick or anyone,

Can someone provide an answer to this please? I am at the same point. For things like my 3-way switch that will be used for GPS does it matter if it isn't perfectly at zero in the center position? On this same switch, for example, I can get the end-points (k-values) set to -125/+125 but then the center = 7. Is that close enough?

Thanks,

Shawn

 

[RTRyder]

Rick or anyone,

Can someone provide an answer to this please? I am at the same point. For things like my 3-way switch that will be used for GPS does it matter if it isn't perfectly at zero in the center position? On this same switch, for example, I can get the end-points (k-values) set to -125/+125 but then the center = 7. Is that close enough?

Thanks,

Shawn

I doubt that it will make any difference at all to the GPS functions. You can easily verify that the various GPS modes are working correctly by connecting your computer to the Navi board with the MKUSB and then bringing up the OSD screen in MKtool while watching the status in the upper right hand corner as you flip through the switch positions. You should see off, position hold, and come home. If you get all three modes, you're done, don't worry about the centering being off a bit.

Ken