Updates, and unstable flight

Spontaneous Projects is a chronicle of all of my projects, a reference for me, and a way to prevent others from making the same mistakes. 

I've ordered the programming cables for the KK2.1 and to program the transmitter, should be here in a week of three... in the mean time I've made the KK2.1 show the correct battery voltage, and I'm working on making it fly properly.

Battery Voltage

The KK board has a in built battery meter, that is meant to be fairly accurate, I haven't tested that yet as I need to replace my multimeter. Finding the information about how to wire it up is a little challenging, and apparently doing so backwards fries the board... 

The pins on the KK 2.1 are shown to the left. Note that the battery pins are inverted reletive to the buzzer, with the positive near the side of the board. 

It is not necessary to connect the negative, as the board is grounded through the ESC's and Reciever, so it is recommended that the negative pin is removed.

The positive battery wire can then be connected to the edge side pin, and you have a battery meter. By using the Battery alarm You will know when the battery is getting low, on my 3 cell (13.3v Batteries) I have the alarm set to Xv, and the motors cut out at X v

Unstable Flight

I still haven't fixed this, and now the LCD on the Board is dead, so there goes any hope of fixing it through the autolevel options.

The issue:

It gets up a little, and after a few seconds it just wobbles, and gets worse until it falls out of the sky.

Possible Causes:

• The wind the last few days might be causing some issues
• The board is not sending signals to the ESC's properly, or a motor is dropping out occasionally
• The physical configuration 0-150-210 might need to be changed to 120-120-120
• The motor mounts may be slipping around on the limbs a little, or the limbs may be shifting slightly
• The PID settings need to be varied a bit, and then it'll fly like a dream
• The board is getting too much vibration

What I've tried:

Waiting for a calm day is time consuming, so we'll skip past that till it happens, 

Signals to ESC's/motors, should be ok, and hard to test

The frame design shouldn't be an issue I think, it's similar to the last design, and the gyros should be able to stabilise it anyway. .

I've adjusted the auto level P gain values a little, but didn't get to stable, decreasing it certainly made it a little better, but not enough.

Further reading suggests that the PID settings elsewhere may help, this guide by FPVcentral in particular looks to be useful.

And now the LCD has died, no substantial crash or anything. The board still arms, so it looks like I just need to get a replacement screen and/or board, so I'll be doing that once I get some stable work. 


Next steps:
I'll try changing the foam and the board mounts to dampen the vibrations a little, and I might reconfigure the physical system to a 120 degree, and I'll definitely be locking the motors in place.
I have some programmers on order, so when they arrive I'll update the firmware. Other than that I think I'll be waiting until I can afford a spare board and a new LCD

It's interesting that I'm having so many issues with this, as other people rave about the stability of this board, I'll keep trying I guess, but I'm really looking forward to knowing enough about how the things work to build my own controllers, so I know what signals they are sending, where, why, and what is going on. I hate black boxes.