Multi Rotor Part 2 - Quadcopter Construction - Step 4

PI Turning and Flight Testing.
"PI Turning is done with propellers fitted, please be careful during this proecess"


KK2.1.5 Flight Controller PI Tuning

  • Tuning is the most important part of getting any quad copter to fly right. Without tuning, the quad copter is very hard to control.
  • I chose to use the KK2.1.5 flight control board for my easy quad copter build because PI tuning is accomplished on this board by setting gain variables used by the firmware loaded on the board with the help of LCD screen, there is no need to connect a computer.
  • The gain variables are set through the lcd menu system on the board. Correctly setting these variables helps the quad fly much better.
  • The creator of the the KK2.0 board and its firmware is Rolf Bakke aka KapteinKUK.
  • The RCGroups forum thread is a great place to download the latest firmware for the board and communicate with others about the board.
  • In KapteinKUK’s forum post he gives very specific directions on setting the gain variables to do PI tuning. 
  • I followed all these directions to tune my quad.
  • I am not a very good pilot and always fly in self-level, however, the tuning process was done with self-leveling off.
  • I went into the first menu item called “PI Editor” and changed all of the variables.
  • I did not change any of the limit values during the tuning process.

Here is what Kaptein KUK has to say about PI tuning :
Roll and Pitch Tuning

  • The right and left roll angle of the quadcopter is controlled by the radio’s aileron stick movement.
  • This is done by moving the right stick on my Mode 2 radio right and left.
  • The forward and back angle of the quadcopter is controlled by the radio’s elevator stick movement.
  • This is done by moving the right stick up and down.
  • By default the KK2.1.5 links the tuning for roll and pitch together and I left it that way for my quad.

Roll/Pitch P Gain Tuning

  • Increase Roll/Pitch P-gain by 10 (5 or less for a small aircraft) at a time, and test your aircraft response by hovering and move the left stick in short and fast movements.
  • I believe when he says “left stick” above, he is using a Mode 1 radio, where the roll and pitch are set up on the left stick. I use a Mode 2 radio where the pitch and roll are on the right side.
  • As I moved the P gain value up by 10 it became more responsive. When I got my P value up to 80 the quad was much more responsive to my stick movements so I left it there.
  • Some folks recommend raising the P value until the quad oscillates and then backing it off a bit, but I just stopped when it felt it stable in after raising it to 80.

Roll/Pitch I Gain Tuning

  • Here, I started with an I gain of 40 which was 50% of the 80 I chose for the P gain. When I got to 60, I noticed it would hold the angle I set by moving the right stick from side to side or forward and back.

Yaw Tuning

  • The rotation of quad copter is controlled by the radio’s rudder stick movement.
  • The rudder is controlled by moving the left stick on my Mode 2 radio right and left.

Yaw P Gain Tuning

  • Here are KapteinKUK’s suggestion on tuning the P gain value for the yaw:
  • Increase Yaw P-gain by 10 (5 or less for a small aircraft) at a time, and test your aircraft response by hovering and move the Yaw control stick until it have yawed about a quarter of a circle, and then center it.
  • I set the P gain to 60. This is where it stayed the most level while yawing.
Yaw I Gain Tuning

  • Finally, here is what KapteinKUK has to say about tuning the P gain value for the yaw:
  • It is generally good to keep the gain values in the low range.
  • Excessive gain may introduce vibration and control issues.
  • I also set the yaw I gain to to 60 to match the P gain.

Self-Level P Gain

  • Under the self-level settings menu there is another P Gain value that is specific to self-level mode.
  • It defaulted to 40 with the version 1.2 firmware that shipped with my board.
  • Version 1.5 and higher versions of the firmware has an improved self-leveling algorithm.
  • Since I prefer to fly in self-level mode, I upgraded my firmware.( I am now using V1.18S1 Pro Firmware by Steveis, so this values and settings have little changes, I will also give the procedure followed by Steveis.)
  • Though it is a little more advanced and may not required, a USBasp AVR can be used to easily load newer versions of the KK2.1 firmware using the LazyZero KKMulticopter Flashtool.
  • The later versions of the firmware have much better self-levelling capability, so I always upgrade my firmware.
  • The self-level P Gain was set to 100 after I changed the firmware to version 1.5.
  • At 100 the quad leveled too quickly and became a little jerky. 
  • When I lowered it to 60 it behaved much better.
  • Example of my final tuned PI gain settings were:

          Roll/Pitch P-gain: 80
          Roll/Pitch I-gain: 60
          Yaw P-gain: 60
          Yaw I-gain: 60
          Self-level P-gain: 60
Note : This is an example, it may not match for your quad copter, you have to obtain the correct gains by trial and error.

Flying - First Flight

  • After doing all of the above stuff, I was ready to take the copter outside to an open space away from people to do an initial flight.
  • Once the copter was in a safe open area with the battery was disconnected, I put the props on the quad .
  • Placed the quad on level ground.
  • Switched on my Tx and confirmed the model selection.
  • Connected the battery to the power harness and immediately stepped away form the quad.
  • Stood at a safe distance from the quad copter and moved my throttle/yaw stick down and right to arm the board in gyro only “rate” mode.
  • Checked to make sure the propellers were rotating correctly by applying a little bit of throttle, but not enough to lift the quad off the ground.
  • I checked that the correct motors were responding to my stick commands by applying a small amount of throttle while testing the aileron, elevator and rudder stick movements. With props on, the quad leaned and turned appropriately.
  • When all props and motors were spinning and responding correctly, I gave the quad enough throttle to lift off and it flew ok with no tuning, but it needed tuning.
  • If I had any problems, I would have immediately lowered the throttle to idle and landed the copter.
  • I also flew it in self-level mode by selecting self level mode with my Tx.
  • It leveled fairly well, but more tuning is required to fly much better.
  • The above steps got the quad copter in the air, but the controls are very loose. Also, the throttle is hard to control and the quad loses altitude when yawing.
  • Tuning will improve these issues greatly.
  • I am not a talented pilot and can’t fly a quad copter that hasn’t been tuned.
  • So beginners should not forget to tune their quads before you demonstrate it in front of people,  which can lead to disaster.
  • General Points - Error messages can only be reset by cycling the power, except for the "sensors not calibrated" message, which is reset after a successful sensor calibration.
  • Error messages include lost RX connection.
  • The KK2.1.5 has an auto-disarm function and will disarm itself after 20 sec if throttle is at idle, for extra safety. it can be turned on/off in "Mode Settings" menu.
  • Lost Model Alarm - The KK2.1 has a lost aircraft alarm and starts to beep (1 sec on and 4 sec off) after 30min of no activity (arm/disarm).

Now we will see the settings for KK2.1.5 , V1.18S1Pro firmware by Steveis.
PI Editor.
  • Enables you to adjust the control loop feedback parameters for Roll, Pitch and Yaw.
  • The proportional term (P) produces an output value that is proportional to the current error value.
  • A high proportional gain results in a large change in the output for a given change in the error.
  • If the proportional gain is too high, the multi copter will overshoot and start to oscillate. 
  • Since the control loop compensates for errors 400 times a second too high a P gain will result in a high frequency oscillation. 
  • If the proportional gain is too low, the control action will be too slow to react on the multicopter and it will be difficult to control.
  • The contribution from the integral term (I) is proportional to both the magnitude of the error and the duration of the error. The integral in a PI controller is the sum of the instantaneous error over time and gives the accumulated offset that should have been corrected previously.
  • If the integral term is too high, the multicopter will start to oscillate.
  • Since the I term is related to the duration of the error over time, too high an I gain will result in a low frequency oscillation.
  • Too low an I gain will result in a less “locked in” feeling.
PI gain adjustment process
  • Go to the "Receiver Test" menu and use the transmitter trims to set the Roll, Pitch and Yaw values to zero.
  • Switch off Self Level.
  • Set the I gain to zero for Roll, Pitch and Yaw.
  • Hover the multicopter and move in one axis (Roll, Pitch or Yaw) and quickly centre the TX control stick.
  • Increase the P gain until the multicopter starts to oscillate when the stick is quickly centred.
  • Decrease the P gain slightly to remove the oscillation.
  • Repeat for all three axis (note, if you have “Link Roll Pitch” set to “Yes” in the Mode Settings menu then adjusting the PI gains and limits for Roll will also adjust the Pitch settings).
  • Increase the Roll and Pitch I gain until it flies straight forward/sideways without pitching up or down. It should feel more “locked in”.
  • Increase the Yaw I gain until Yaw feels “locked in”. You will see most impact on a tricopter. Leave as default for quadcopter.
  • Note, if you have I gains set and you operate your multicopter on the ground, you will find that motors will start to increase in speed while others decrease. 
  • This is the I term working to compensate for long term errors, but on the ground, or in your hand (without props on of course) it doesn’t allow the I term to move the multicopter to compensate for the error.
  • A tuning video can be found here: http://www.youtube.com/watch?v=YNzqTGEl2xQ
PI limits
  • The PI limits are the percentage of motor power that can be used to apply the correction.
  • These should be left at default. For example, a limit of 20 (20% motor power to apply the correction) will allow 80% of motor power to be used for commanding a change in direction from the receiver.
SAFE Screen Information - Pre-flight

  • If the SAFE screen says ERROR, you must fix that error before you can arm it.
  • You will see the actual error on the display.
  • You may have to power cycle the KK2.1.5 to clear an error after fixing it.
  • Top right displays the profile being used (P1 or P2) or tells you which stick scaling and PI profile you are using (PI1 or PI2).
  • It will tell you if Self Level is on or off.
  • The Battery (Batt) voltage will be displayed if you have connected the flight battery +ve to the KK2.1..5 battery monitor pin (pin closest to the edge of the board).
  • Temp is the MPU6050 internal temperature.
  • Roll and Pitch Angle will appear after arming and disarming. They display the angle of the KK2.1.5 after arming and disarming.
  • If you have the Alternative SAFE screen layout selected in Misc Settings 2, it displays the last Motor Layout selected (this is just a guide as you may have changed the settings in the Mixer Editor).
  • Pressing button 4 takes you into the MENU.

Post-flight

  • If the SAFE screen says ERROR, you must pay attention.
  • You will see the actual ERROR on the display. It will most likely be “Error: no yaw input” which means you had a receiver failure during flight.
  • The top left corner will display a number if the KK2.1.5 code took longer than expected to execute during flight, the number of times this happened will be displayed.
  • This shouldn’t happen. If it does, it could indicate a fault with the board.
  • The Roll and Pitch Angle will appear.
  • Pressing button 4 takes you into the MENU.
Problems with Self Level

  • The following will cause accuracy issues with Self Level.
  • Vibrations are the most common cause – balance your propellers, including the hubs.
  • Balance your motor bells.
  • Ensure you don’t have bent motor shafts.
  • Ensure the engineering quality of your prop adapters is acceptable.
  • Finally, dynamically balance your motor with prop and prop adapter.
  • Arming outside the 20deg limit – arm the multicopter when it is level.
  • Exceeding gyro rate while flying – ensure the gyro rate is higher than your expected manoeuvres. 
  • This will cause catastrophic issues if self level is switch on as the KK2.1.5 will have no idea which way is up.
  • Temperature changes – let your multicopter acclimatise to the temperature you are going to fly in before arming.
  • Drifting gyro – gyros drift over a short period of time (minutes). During long flights, you may need to land and rearm to recalibrate the gyros.

Pre-flight checks and setup
Initial Setup of the KK2.1.5 disconnected from Multicopter
  • Remove the KK2.1.5. from the Multicopter.
  • Power up the KK2.1.5 using a 4 cell battery pack or BEC.
  • Select the required Motor Layout.
  • Select the Receiver Type in Mode Settings.
  • If necessary, change Channel Mapping.
  • Power down the KK2.1.5.
  • Set up your transmitter as a simple aircraft with no mixing.
  • If necessary, bind your transmitter to the receiver.
  • Power up your transmitter.
  • Connect the receiver to the KK2.1.5.
  • Power up the KK2.1.5 and receiver.
  • Refer to the Receiver Test section and set up correctly.
  • Power down the KK2.1.5 and receiver.
  • Power down your transmitter.
Setup of the KK2.1.5 mounted in the Multicopter
  • Remove all propellers.
  • Mount the KK2.1.5 on the frame with the LCD facing front and the buttons facing back.
  • Connect the receiver to the pins on the left side. The negative (black or brown) lead towards the edge of the KK2.1.5.
  • Connect the ESCs and servos to the pins on the right side. The negative (black or brown) lead towards the edge of the Kk2.1.5.
  • Connect buzzer and battery voltage monitor if required.
  • Turn on your transmitter.
  • First we must set the throttle limits on the ESCs
  • Set your transmitter throttle stick to maximum
  • Press and hold down buttons 1 & 4 on the KK2.1.5
  • Turn on the power to the Multicopter
  • Wait for the ESC to beep its full throttle calibrated signal. Takes a few seconds, depends on the ESC
  • Lower the throttle to idle
  • Wait for the idle throttle calibrated signal
  • Release buttons 1 & 4.
  • Place the Multicopter on a level surface.
  • Calibrate the accelerometers using the ACC Calibration menu option.
  • There shouldn’t be any errors on the SAFE screen but if there are, they need correcting.
  • All propellers should still be removed.
  • Arm the KK2.1.5 by moving the throttle to minimum and yaw to the right for a few seconds and apply a little throttle.
  • Ensure all motors spin in the direction as indicated by the Motor Layout. 
  • If a motor needs reversing, you need to remove two of the three motor wires from the ESC and swap them over.
  • The KK2.1.5 cannot be used to reverse the direction of a motor.
  • With the motors running, if you push the roll/pitch stick towards a motor, it should slow down and the opposite motor should speed up. If not, check the stick directions in Receiver Test.
  • With the motors running and the sticks central, dip one of the motors and it should speed up. If not, check the stick directions in Receiver Test.
  • Disarm the KK2.1.5 by moving the throttle to minimum and yaw to the left for a few seconds.
  • Turn off the Multicopter.
  • Turn off your transmitter.
First Flight
  • You are now ready to fly.
  • Ensure the propellers are placed on the right motors for the direction that they are turning.
  • Remember to turn your transmitter on first and turn it off last.
  • Turn your transmitter on.
  • Turn on the Multicopter.
  • Step away at least 5 meters.
  • Arm the KK2.1.5 by moving the throttle to minimum and yaw to the right for a few seconds.
  • The buzzer will sound and the KK2.1.5 LED will light.
  • Turn self level off.
  • Gently lift the throttle.
  • If it wants to tip over right away, check your motor connections and your custom made mixer table if you have one.
  • If it’s a tricopter and it starts to pirouette on take off, go to the Mixer Editor and select the channel that the servo is connected to (usually output 4 or 7) and change the Rudder value from +100 to -100.
  • If it shakes and maybe climbs after it’s airborne, adjust the Roll and Pitch P Gain down.
  • If it easily tips over after it's airborne, adjust Roll and Pitch P Gain up.
  • Increase the Roll and Pitch I gain (note the difference from P gain) until it flies straight forward without pitching up or down.
  • Once you have adjusted your PI Gains to your satisfaction, turn self level on and adjust the Self Level P gain.
  • More detailed PI gain setting instructions can be found in the PI Editor section of manual.
  • Adjust Stick Scaling to your liking.
  • After flying, turn off the Multicopter.
  • Then turn off your transmitter.
  • Stick Scaling and overflying the gyro rate:
  • Gimbal setup:
  • Calibrating the ESCs:

Information of firmwares:-
HW Version 2.1.X, SW Version by Steveis
V1.18S1Pro for KK2.1.X
V1.17S1Pro for KK2.1.X
V1.16S1Pro for KK2.1.X
V1.15S1Pro for KK2.1.X
V1.14S1Pro
HK V1.6 for KK2.1.X

Happy Flying!!!!!!!!!
Coming up Next :- Basic Trainer Airplane Construction using Coroplast Sheet (Sun board)

Multi Rotor Part 2 - Quadcopter Construction - Step 3

Setting up KK2.1.5 FC for Quad Copter.
Multi-Rotor Safety - Before doing any setup Please remove all the propellers.
KK 2.1.5 flight control board.
  • A host of multi-rotor craft types are Pre-installed, simply select your craft type, check motor layout/propeller direction, calibrate your ESCs and radio and you’re ready to go.
  • All of which is done with easy to follow on screen prompts.

If you want to upgrade the board with a new firmware.
Warning - Use the firmware at your own risk.

  1. Choose the programmer - USBasp, http://www.fischl.de/usbasp/(usbasp)
  2. Choose port - usb.
  3. Choose your controller: HobbyKing KK2.1 and 2.1.5 (64 kB flash)
  4. Select Flashing firmware tab.
  5. Flashing - Repository tab selected - You will get 3 options - all firmware type - Openaero ( This is for fixed wing plane) - KK2.1
  6. Select KK2.1
  7. In firmware window you can see all avialiable versions. Select the one you want to flash or on right side of this window you can see a blue icon, if you click on this you can select any other version firmware you have stored in your pc.
  8. Next to the blue icon you can see a green icon , if you click on this the selected firmware from repository will be flashed to your board.
  9. Once you click green or blue icon you can see the process and completion report in the bottom window.

  • I hope this information will help you for flashing the HK KK2.1.5 board with new firmware.
Warning - Never do any type of testing with propeller on.
Always remove propellers before doing any type of adjustment or setting change. If not handled properly Quad copters are extremely dangerous.
Initial Set Up.
Always turn the transmitter 'ON' before the receiver and turn the receiver 'OFF' before the transmitter.
1. Programming the ESCs

  • Almost all the ESCs around are similar to the one I used and that can be programmed with a programming card or with your Tx-Rx.
  • I programmed my ESCs using my Tx-Rx (with Propellers Off!).
  1. Dissconnect all of the ESC BEC/signal connector from the KK2.1.5 flight controller.
  2. Connect the battery to the power harness.
  3. Connect one of the ESC BEC/signal connectors with power wire (Red) to the Rx Throttle Channel (Ch 3).
  4. Follow the instructions given in the ESC manual to set the required values.
  
Here is my settings of ESCs for Quad copter.
  • Brake – OFF
  • Battery Type – Li-ion/Li-poly
  • Cut Off Mode – Soft-Cut
  • Cut off Threshold - Medium
  • Start Mode – Normal
  • Timing - High
If you are using any other make ESC, follow the set up instructions given in its manual.
5. Repeate these steps for the remaining ESCs.
6. Reconnect all of the ESC BEC/Signal connectors to the KK2.0 flight controller in according to the picture from Part 2. ( Connect power wire (Red) of Motor 1 ESC only to KK2.1.5 board)
2. Binding the Radio
  • The Avionic 6 channel radio transmitter and 6 channel receiver , or any other Tx-Rx set, have to be bound together to be able to talk to each other.
  • To bind them follow the steps given by the manufacturer, or read my post about Radio Control for detailed information.
3. Setting Up KK 2.1.5 Flight Controller Board
  • The KK2.1.5 board I received was loaded with the version 1.6 of the firmware.
  • I flashed the board with the most current version V19S1 Pro by Stevesis, this firmware version has better self leveling.
  • The pre-installed firmware can be upgraded as I described in this post.
  • But to keep it simple you can use what is already on the board.
  • Ckeck the following,
  • Mounted the FC on the frame with the LCD facing front and the buttons facing back. 
  • Connected the receiver outputs to the corresponding left-hand side of the controller board. The pins are defined as: Ground, +, Signal. Ensure the negative (black or brown) is orientated so that it is on the pin that is nearest to the edge of the Flight Controller Board, so looking at the board the color sequence will be Black, Red and Orange. The channels are connected as follows from the front of the board towards the push buttons.
  • Connected the ESC’s to the right side of the Flight Controller Board. M1 is towards the front of the board and M8 is nearest to the push buttons. The negative (black or brown) lead towards the edge of the FC.
  • DO NOT MOUNT THE PROPELLERS AT THIS STAGE – FOR SAFETY REASONS.
  • The Flight Controller Board must always have a source of +5v from an ESC, either one of the motors ESC or from a separate unit feeding the Receiver.
  • Set up a new model on your transmitter and use a normal airplane profile and check the binding of Receiver to the Transmitter.
  • Here is an overview of the specific steps I followed to set-up this quad:
  • Sensor Test – I performed this test first to confirm that all the sensors on my board were working correctly.
  • Powered up my KK 2.1.5 board by plugging in the battery (with Propellers Off!). The KK 2.1.5 board displayed SAFE.
  • Brought up the main menu by pressing the MENU button from the SAFE display.
  • From the main menu, I pressed the DOWN button until I got to Sensor Test.
  • Pressed the ENTER button to do the Sensor Test.
  • All of my sensors showed “OK”, so I knew I had a good board.
  • Sensor Test displays the raw gyroscope and accelerometer sensor values.
  • Must show "OK" when stationary.
  • If it says “Not OK” when stationary, the sensor chip is faulty.
  • Move the KK2.1.5 around to see that the numbers change. In this case, it is fine if the sensors start reading “Not OK”.
  • Pressed BACK button until I returned to the SAFE display.


  • Load Motor Layout
  • Displays a graphical representation of the motors and servos.
  • Can be used to check the Motor direction and which outputs to connect the ESCs and Servos.
  • Enables you to load a pre-configured multi copter setup.
  • Select from a list of pre-configured multi copter types.
  • I configured the KK2.1.5 board to be a quad copter in the X motor configuration.
  • Brought up the main menu by pressing the MENU button from the SAFE display.
  • From the main menu, I pressed the DOWN button until I got to Load Motor Layout.
  • Pressed the ENTER button to see the different motor layouts available.
  • From the main menu, I pressed the DOWN button until I got Quadro copter X mode.
  • Pressed the ENTER button to set the KK2.1.5 configuration to Quad copter X mode.
  • The LCD asked me “Are you sure?” and I pressed the ENTER button to say that I am sure.
  • Then selected show motor layout and checked all the motor connection and its direction of rotation for a qaud copter X.
  • Pressed BACK button until I returned to the SAFE display.
  • Note that this does not set the motor direction.
  • That is set by the wires connected between your motor and ESC.
  • If you need to reverse your motor, reverse two of the three motor wires.
  • Show Motor Layout
  • Enables you to see which Motor Layout you have selected and any changes you make in the Mixer Editor.


  • Receiver Test 
  • Displays the receiver signal inputs.
  • If “No signal” is displayed, check connection to the receiver. Also ensure your receiver is working with your transmitter by connecting a servo to a spare receiver output.
  • Use the transmitter trims to set the Roll, Pitch and Yaw values to zero.
  • Ensure the Throttle is 0 and says “Idle” at low throttle and at full throttle, it is greater than 90 and says “Full”. 
  • Adjust transmitter throttle trim for low throttle and end point for high throttle.
  • Roll, Pitch and Yaw should all read between -100 to -90 and 90 to 100 at maximum stick travel.
  • Adjust transmitter end points to achieve this. Do not exceed +/-110.
  • Ensure Roll, Pitch and Yaw stick commands are correctly shown as Left, Right, Forward, Back.
  • If not, reverse the throws in your transmitter.
  • Arm Test will normally show “Safe Zone”. At minimum throttle (throttle 0) and full right yaw, it should display “Arm”. 
  • At minimum throttle (throttle 0) and full left yaw, it should display “Disarm”.
  • Providing there are no ERRORS on the SAFE screen, your multi copter should arm and disarm.
  • Check the Auxiliary channel input and reverse the channel in your transmitter if necessary.
  • Do not use dual rates on your transmitter. Use Stick Scaling instead. This is very important on the Yaw channel as a low rate on the Yaw will prevent Arming and Disarming.
  • If the receiver values appear random, check the following:
  • Receiver connection(s).
  • Mode Settings, Receiver is correct.
  • If Mode Settings Channel Map is “Yes”, check Receiver Channel Map.








  • Sensor Calibration – I performed this calibration to correctly calibrate the accelerometers and gyros on my quadcopter.
  • ACC Calibration
  • Calibrates the accelerometers
  • Set the multicopter level by placing the quadcopter on a level surface.
  • From the main menu, I pressed the DOWN button until I found the Sensor Calibration menu item.
  • Pressed the ENTER button to do Sensor calibration.
  • Do not move the multicopter during calibration.
  • The LCD will tell you the sequence.
  • Pressed the CONTINUE button to continue.
  • The LCD displayed various information about the calibration it is doing.
  •  Finally, the gyros and accelerometers have some values and OK displayed next them.
  • Pressed the CONTINUE button a couple of times to confirm and take me back to the main menu.
  • Pressed BACK button until I returned to the SAFE display.
  • You will not be able to Arm the KK2.1.5 until the calibration routing has been successful.
  • If the calibration failed and you did not move the multicopter during calibration then you have a faulty sensor chip.
  • Gyro Bubble
  • Displays a graphical display of the gyroscope.
  • This could be used to check for vibrations but you would need to connect the motor ESCs direct to a receiver.
  • This is very dangerous and needs to be done with caution.
  • The bubble should be in the centre of the crosshair. If it is not, arm and disarm the KK2.1.5 to calibrate the gyro again.
  •  Moving the board will demonstrate the sensitivity of the gyro at different settings.
  • The gyro bubble may drift over time or if the temperature changes.
  • Acc Bubble
  • Displays a graphical display of the accelerometer.
  • When level, the bubble should be in the middle of the crosshair. If not, the ACC Calibration routine should be performed.
  • Moving the board will demonstrate the sensitivity of the accelerometer at different settings.
  • The accelerometer bubble may drift if the temperature changes.

  • ESC Calibration – Props Off! – My props had been off the whole time.
  • In this step you can calibrate all the four ESCs together. ( If you have previously calibrated your ESC individually, it is better to calibrate all of them together)
  • But it is critical that they were off now, because ESC calibration can easily go wrong and I did not want to lose a finger!.
  • ESC calibration gives all of my ESCs a consistent calibration that matches the throttle range of my transmitter.
  • It is done with the throttle fully up. 
  • If something goes wrong and my throttle is fully up with the props on, I cannot predict what type of accident may happen.
  • Again, make sure props are OFF! Ah yes, they were, and had been the whole time! 
  • Unplugged the battery on the quad from the power harness.
  • Turned on the power to my transmitter
  • Moved the throttle lever all the way up on my transmitter
  • Plugged the battery on my quad into the power harness keeping pressed buttons 1 and 4  together on the KK2.1.5 board.
  • Continued to hold down buttons 1 and 4. The LCD displayed “Calibrating ESCs” and the ESCs made two short beeps signalling they were ready to be calibrated.
  • While holding down buttons 1 and 4, I steadily moved the throttle stick on my radio from full throttle all the way down to cut off.
  • The ESCs made one long beep signalling that they had been calibrated.
  • Released buttons 1 and 4 on the KK2.1.5 board and returned to the SAFE display.
  • Armed the board with the props off by holding the left stick down and to the right.
  • The LCD displayed “ARMED”
  • Moved the throttle up a bit to see that all four motors started together and properly calibrated.
  • With the throttle partially up, I also moved the other sticks to see if I heard a proper response from the motors.
  • Checked the ailerons by moving the right stick left which sped up the two motors on the right side, and then right which sped up the two left motors.
  • Checked the elevators by moving the right stick up which sped up the two rear motors, and then down which sped up the two front motors.
  • Decided to check the yaw on my first flight.
  • Disarmed my quadcopter back into “Safe” mode by moving the left stick down and to the left.
  • The board went back in to safe mode and I disconnected the power.
Mode Settings - Various settings – First option listed is the default
  • Self-Level
  • Aux – AUX channel controls the self-levelling function.
  • Stick – Turn on Self-levelling by holding the aileron to the right when arming or disarming. Turn it off with left aileron. 
  • Note, if you only connect a 4 channel receiver to the KK2.1.5 with Roll, Pitch, Throttle and Yaw then set Self-Level to Stick.
  • Always – Self level is always on.
  • Link Roll Pitch
  • Yes – Changes to the PI Settings for both Roll and Pitch when you make changes.
  • No – You need to update the Roll and Pitch PI Settings separately.
  • Auto Disarm
  • Yes – will automatically disarm after 20 seconds when armed and throttle is set to zero. (If Lost Model Alarm is set to “Yes” then you can’t switch Auto Disarm Off).
  • No – No Auto Disarm and no Lost Model Alarm.
  • Receiver (if you change the receiver, you need to power cycle the KK2.1.5)
  • Std – Standard PPM receiver with 4 or 5 (inc Aux) connections to the KK2.1.5 inputs.
  • CPPM – Combined PPM receiver connection. This is all receiver channels combined/multiplexed onto one cable that should be connected to input 1 (top input).
  • DSM2 – A DSM2 satellite receiver (not a main DSM2 receiver) connected to input 3 (middle input) via a level changing cable. Note that the receiver needs to be bound to the KK2.1.5, not a normal receiver. To bind the DSM2 satellite, hold buttons 2&3 down on power up. The satellite will flash rapidly and you should follow your transmitter/receiver binding process. Beware that some receivers bind and set the channels to a failsafe position. You may need to rebind after you set the correct directions using the Receiver Test menu.
  • DSMX – A DSMX satellite receiver (not a main DSMX receiver) connected to input 3 (middle input) via a level changing cable. Note that the receiver needs to be bound to the KK2.1.5, not a normal receiver. To bind the DSMX satellite, hold button 3 down on power up. The satellite will flash rapidly and you should follow your transmitter/receiver binding process. Beware that some receivers bind and set the channels to a failsafe position. You may need to rebind after you set the correct directions using the Receiver Test menu.
  • SBus – An SBus receiver connected to input 3 (middle input) via an inverter cable.
  • Channel Map
  • No – With a standard receiver, it is generally assumed that you will not map any channels.
  • Yes – Swap channel order using Receiver Channel Map.
  • Lost Model Alarm
  • Yes – When the KK2.1.5 Auto Disarms, it will sound the buzzer. Note that Auto Disarm is forced on when “Yes” is selected.
  • No – Lost Model Alarm disabled. Set to “No” to allow you to set Auto Disarm to “No”.
  • Stick Scaling
  • These settings enable you to adjust the sensitivity of the transmitter stick. A higher number gives a more sensitive response. It is used in preference to increasing the rates in your transmitter. The default values are low for beginners that may not appreciate how sensitive the transmitter sticks can be in controlling a multicopter.
  • If you want to flip and roll, you will need to increase the Roll and Pitch values.
  • Increase the Yaw value to yaw to your liking.
  • Throttle is best left at 90. If you increase it too much, full throttle on the transmitter will run the motors at maximum and leave no headroom for the PI control loop to adjust the motors to keep it steady. If you set the value to a negative value, it will reverse the transmitter channel. This is to enable the use of transmitters that don’t allow you to change the direction for a channel. It only works for roll, pitch and yaw
  • Misc. Settings 1- Various settings
  • Minimum throttle – ensures all motors start at the same rate. If some motors do not start when you arm, increase this value. This value also allows you to change the motor speed if you have Spin on Arm enabled.
  • Height Dampening – Compensates for the drop in height when the multicopter is banked in a turn. Normally, the pilot will compensate for this dropping effect by increasing the throttle slightly. The default is 0 (disabled).
  • Height D. Limit – The percentage of motor power that can be used to apply the correction.
  • Alarm 1/10 volts – When the flight battery +ve terminal is connected to the KK2.1.5 battery monitor pin, this sets the voltage alarm threshold when the buzzer sounds. If you want the buzzer to sound at 10.2 volts or less, set this value to 102. The default is 0 (disabled).
  • Servo Filter – Software filter that smooths out the control signal to servos. Set this value as low as possible.
  • Acc SW filter – Software filter in the KK2.1.5 code that smooths out the accelerometer reading. This value can be increased to mask vibrations. The default is 8 which results in a low pass filter coefficient of 0.03 (8/256). It is best to leave it at this value.
  • Misc. Settings 2 - Various settings – First option listed is the default • Board Offset (see Appendix H)
  • 0 – Zero degrees offset. KK2.1.5 board faces forward.
  • +45 or -45 – KK2.1.5 board is mounted at 45 degrees.
  • +90 or -90 – KK2.1.5 board is mounted at 90 degrees.
  • 180 – 180 degrees offset. KK2.1.5 board faces backwards.

  • Spin on Arm
  • No – When armed, with throttle at zero, motors are stopped.
  • Yes – When armed and throttle is at zero, motors run at the speed set by Minimum Throttle. This is useful if you want to fly and never want your motors to stop in flips and rolls for example.
  • SS Gimbal
  • No – A normal camera gimbal is being used with one servo for Pitch and one for Roll.
  • Yes – Super Simple Gimbal is used where both servos work together to move Pitch and Roll in a differential configuration.
  • Gimbal Control
  • No – Gimbal offset is fixed as set in Camera Stab Settings.
  • Aux – Gimbal Pitch offset can be changed using the Aux channel (see Appendix B). This enables you to change the Pitch offset with a Standard PPM receiver.
  • 6&7 – Gimbal Pitch and Roll offset can be changed using the receiver Channel 6 and 7 outputs. Note that you will need to use this feature with a CPPM receiver, satellite receiver or SBus receiver.
  • Alt Safe Screen
  • No – Standard SAFE screen layout
  • Yes – Alternative SAFE screen layout which displays the last Motor Layout selected (this is just a guide as you may have changed the settings in the Mixer Editor).
  • Batt Volt Trim - Enables you to adjust the battery voltage reading by 0.1 volt increments if you are not satisfied with the value shown with the default trim value of 0. The range is +/- 0.6 volts. The value shown is 1/10th of a volt so a value of 6 is 0.6V.
  • Misc. Settings 3 - Various settings – First option listed is the default
  • Servos on Arm
  • No – When armed, with throttle at zero, servos are centred. Tricopter users will probably want to leave it at this setting so that the yaw servo doesn’t move when arming and disarming.
  • Yes – When armed and throttle is at zero, servos move. This is useful if you want to fly and never want your servos to automatically centre.
  • Profiles
  • Enables the use of two user profiles to store settings
  • Current Profile
  • P1 – Profile 1 selected (will be forced to P1 if you select “Yes” for Switch SS & PI).
  • P2 – Profile 2 selected.
  • Each Profile has all of its own settings, including Receiver type, Motor Layout and ACC Calibration which will need to be set up and calibrated before you can arm the board when the profile is selected.
  • You will need to power cycle the KK2.1.X if you change to a profile with a different type of Receiver.
  • The SAFE screen will display P1 or P2 in the top left of the display to indicate which profile is being used.
  • Switch SS & PI
  • No – Enables you to select either Profile 1 or Profile 2.
  • Yes – Forces you to use Profile 1 as the main profile. However, when you switch the Aux switch, it will use the Stick Scaling and PI settings from Profile 2. If you don’t want to use Self Level when switching to the Stick Scaling and PI settings from P2 you can set Self Level P Gain to zero in P2 or you can set Self Level to “Stick” in P1.
  • To set up the Stick Scaling and PI Gains and Limits in P2, you first have to set Switch SS & PI to “No” so that you can set the Current Profile to “P2”. It is not necessary to select a motor layout or ACC calibrate P2 if using this feature. If you leave the PI settings the same in both profiles but change the Stick Scaling, switching will act like dual rates on your transmitter.
  • The SAFE screen will display PI1 or PI2 in the top left of the display to indicate which set of Stick Scaling and PI settings are being used, depending on the setting of the Aux channel/switch. You will also see if self level switches On or Off when switching between PI1 and PI2.
  • Debug - Various values used for debugging purposes.
  • Version - Displays current firmware version information.
  • Factory ResetPerform a complete factory reset on all profiles.
Note : The above mentioned settings may have little variations as per the firmware version you flash into your KK2.1.5 FC Board.
We will summarise the Initial Setup of the KK2.1.5
  • Disconnected from Multicopter
  • Remove the KK2.1.5. from the Multicopter.
  • Power up the KK2.1.5 using a 4 cell battery pack or BEC.
  • Select the required Motor Layout.
  • Select the Receiver Type in Mode Settings.
  • If necessary, change Channel Mapping.
  • Power down the KK2.1.5.
  • Set up your transmitter as a simple aircraft with no mixing.
  • If necessary, bind your transmitter to the receiver .
  • Power up your transmitter.
  • Connect the receiver to the KK2.1.5.
  • Power up the KK2.1.5 and receiver.
  • Refer to the Receiver Test section and set up correctly.
  • Power down the KK2.1.5 and receiver.
  • Power down your transmitter.
Setup of the KK2.1.5 mounted in the Multicopter
  • Remove all propellers.
  • Mount the KK2.1.5 on the frame with the LCD facing front and the buttons facing back.
  • Connect the receiver to the pins on the left side. The negative (black or brown) lead towards the edge of the KK2.1.5.
  • Connect the ESCs and servos to the pins on the right side. The negative (black or brown) lead towards the edge of the KK2.1.5.
  • Connect buzzer and battery voltage monitor if required.
  • Turn on your transmitter.
  • First we must set the throttle limits on the ESCs
  • Set your transmitter throttle stick to maximum
  • Press and hold down buttons 1 & 4 on the KK2.1.5
  • Turn on the power to the Multicopter
  • Wait for the ESC to beep its full throttle calibrated signal. Takes a few seconds, depends on the ESC
  • Lower the throttle to idle
  • Wait for the idle throttle calibrated signal
  • Release buttons 1 & 4.
  • Place the Multi copter on a level surface.
  • Calibrate the accelerometers using the ACC Calibration menu option.
  • There shouldn’t be any errors on the SAFE screen but if there are, they need correcting.
  • All propellers should still be removed.
  • Arm the KK2.1.5 by moving the throttle to minimum and yaw to the right for a few seconds. and apply a little throttle. Ensure all motors spin in the direction as indicated by the Motor Layout. 
  • If a motor needs reversing, you need to remove two of the three motor wires from the ESC and swap them over.
  • The KK2.1.5 cannot be used to reverse the direction of a motor.
  • With the motors running, if you push the roll/pitch stick towards a motor, it should slow down and the opposite motor should speed up. If not, check the stick directions in Receiver Test.
  • With the motors running and the sticks central, dip one of the motors and it should speed up. If not, check the stick directions in Receiver Test.
  • Disarm the KK2.1.5 by moving the throttle to minimum and yaw to the left for a few seconds.
  • Turn off the Multi copter
  • Turn off your transmitter.
  • Now you are ready for initial PI turning and flight testing.
Next - PI Turning and Flight Testing.

Multi Rotor Part 2 - Quadcopter Construction - Step 2

Building a 550 mm Quad Copter using PVC pipes.
Materials required.
  1. Arrange or by round PVC pipe of 3/4" dia,  8 pcs T-joint 3/4",  4 pcs L joint 3/4" and one 4 way split joint 3/4".
  2. Get solvent cement used by plumbers for sealing and joining PVC pipes.
  3. Buy glues, Flex Quick (cyno based instant adhesive), Araldite ( standard epoxy adhesive), Fevicol (synthetic resin adhesive).
  4. Get 2 pcs of aluminium sheet of 1.5 to 2 mm thickness or 2 pcs of 5 mm poly carbonate sheet ( size 6*16 cm and 8*11 cm).
  5. Sufficient number of Cable ties.
  6. Nut and bolts as per the pipe diameter, small screws.
  7. Bullet connectors for joining ESC, Motor and battery.(minimum 22 pairs of 3.5 or 4 mm bullet connectors).
  8. 12 to 16 AWG Electric cable for making ESC connection harness (RED and BLACK).
  9. Colored tapes for marking and decorating frame.
  10. Velcro for attaching battery.
  11. A round or square transparent plastic container to make the dome.
  12. Spacers as required, made out of empty sketch pen shell.
  13. Cycle tube to make rubber pads for vibration dampening.
Electronics Required - (You can change the configuration as per your requirement)
1. BLDC outrunner motors - 04 nos.
  • I used motors with the following specifications, 
  • MOTOR TOP STAR - KV: 1000
  • Dimensions (mm):Φ22×10 - Weight (g): 47
  • Shaft Diameter (mm):Ф3 - Battery: 3×Li-Poly
  • No load current (11.1V): 0.6 A - No load RPM:11500
  • Load current (11.1V):11.6 A - Max Power(W):130
  • load RPM: 7196 - Test Thrust (g):620
  • Test prop:9 x 50", 10 x 4.5" 10 x 4.7"
2. ESCs - 04 nos.
  • I used ESCs with the following specifications,
  • IPEAKA 30 Amp
  • 2-4 LiPo - 5-12NiMh
  • BEC 5V 2 amp.
3. Propellers (2 clockwise-2 anticlockwise)- 04 nos.
  • I used 10 x 4.7 Slow Fly propellers.
4. LiPo Battery - 01
  • I used Zippy Flightmax 3000 mAh 30C 3S LiPo.
5. Flight Controller -01
  • I used KK 2.1.5 LCD Flight Controller.

  • The KK2.1.5 packing is new with updated sensors, memory and header pins.
  • The KK2.1.5 is next big evolution of the first generation KK flight control boards.
  • The KK2.1.5 was engineered from the ground up to bring multi-rotor flight to everyone, not just the experts.
  • The LCD screen and built in software makes install and setup easier than ever.
  • A host of multi-rotor craft types are pre-installed, simply select your craft type, check motor layout/propeller direction, calibrate your ESCs and radio and you’re ready to go!
  • All of which is done with easy to follow on screen prompts!
  • The original KK gyro system has been updated to an incredibly sensitive 6050 MPU system making this the most stable KK board ever and allowing for the addition of an auto-level function.
  • At the heart of the KK2.1.5 is an Atmel Mega644PA 8-bit AVR RISC-based microcontroller with 64k of memory.
  • An additional polarity protected header has been added for voltage detection, so no need for on-board soldering.
  • A handy piezo buzzer is also included for audio warning when activating and deactivating the board.
  • The KK2.1.5 added polarity protection to the voltage sense header and a fuse protected buzzer outputs, in case something is accidentally plugged in incorrectly.
  • The voltage sense line has been updated for better accuracy.
  • The board is clearly labeled and the voltage sense line color has been changed to red for easy identification, making installation and connections a snap.
  • If you’re new to multi-rotor flight or have been unsure about how to setup a KK board then the KK2.1.5 was built for you.
  • The 6 Pin USBasp AVR programming interface ensures future software updates will be quick and easy.
  • Specs:  Size: 50.5mm x 50.5mm x 12mm     Weight: 21 gram (Inc Piezo buzzer),          IC: Atmega644 PA     Gyro/Acc: 6050MPU InvenSense Inc.,  Auto-level: Yes        Input Voltage: 4.8-6.0V     AVR interface: standard 6 pin.      Signal from Receiver: 1520us (5 channels)      Signal to ESC: 1520us         Firmware Version: 1.6:             Pre-installed firmware. - Dualcopter,  Tricopter,  Y6,  Quadcopter +,  Quadcopter X,  Hexcopter +,  Hexcopter X,  Octocopter +,  Octocopter X,  X8 +,  X8 X,   H8,   H6,   V8,  V6,   Singlecopter 2M 2S,   Singlecopter 1M 4S,  (Custom Mix via the "Mixer Editor" option)
6. Tx-Rx -01
  • Avionic 6Ch Computer Tx-Rx.
Tools Required.
  • Hand drill or Power drill with drill bits.
  • Handsaw blade.
  • Screw driver set.
  • Knife.
  • A good quality plastic/wood/steel rule.
  • Soldering iron, solder wire and soldering paste.
  • Cutting pliers.
  • Ellen key set.
  • Nose pliers.
  • Marker pen.

550 mm PVC Quad Copter Design.
 

Frame -
  • For frame I chose round PVC pipes used for electrical wiring.
  • Sometime you can find waste pieces of this in a junk yard, make us
  • e of that.
  • If you can't manage then you can buy it from any local hardware shop.
  • Use a handsaw blade to cut the PVC pipes as per the dimensions given above.
  • To decide the arm length add the propeller size from the middle of the quad copter and that's where the motor will go.
  • Cut aluminium plate or poly carbonate sheet for Top and Bottom plates as per the dimensions given in the drawing.
  • That's all the cutting work you have to do.
Frame Assembly.
  • Dry fit all the PVC parts together as given below.
  • Do a measurement of the frame after dry fitting to match with your drawing.
  • Some adjustments will be required because when you insert the pvc pipe into T and L joints all may not go inside the same length.
 
  • Now do all required markings with a permanent marker pen.
  • Such as arm number, motor rotation direction, center of all outer T joints, center line from one end to other end, motor mount, etc..
  • Draw a line tip to tip through center on both arms, make sure that it meets exactly in center of round PVC union (if not do necessary adjustments).
  • Once again measure all four arm lengths from center and between arms, make sure that all measurements are same (less than +/- 5 mm tolerance can be given).
  • Equal length and spacing between the arms are most important because it directly affect the flight performance of your Quad.
  • Mar the center of outer T, motor mount center should go through this point.
  • Take the motor mount and mark out where you need to put the screws. This is one of the major things to do because even if one of the screws is a little off it can rattle the motor out completely.
  • Before drilling holes for mounting the motors, once again measure motor center to motor center and one arm to other arm and make sure that all measurements are equal.
  • Now you can drill holes.
  • Take the Top and bottom plates, place them on the frame and do the markings on the plates and pvc frame for drilling holes for fitment.
  • Now before taking the parts apart,  mark all the parts and their position for identification when you do the final assembly.
  • Any coding system which you can understand afterwards can be used.
  • We can do the covering the arms with color tapes after gluing the joints and drilling holes, otherwise all the markings will get covered.
  • The purpose of coloring the arms is to find out the orientation of your Quad Copter during flying and to give an attractive look.
  • If you are satisfied with the frame preparation, now you can start gluing it.
  • Gluing the joint can be done in two ways, you dismantle the entire frame and start gluing each joint from step one, or glue one by one joint without dismantling fully.
  • Method one will be more easy and accurate way to do it (provided you done proper markings on all parts).
  • In every step of gluing keep measuring the arm length and spacing. 
  • Maintain the direction and flatness of all T joints.
  • Opening of the 4 way union will face downwards.
  • You should do the gluing by keeping the frame on a flat surface.
  • Any adjustments required is to be done before the glue dries.
  • When you complete gluing of all joints your frame is ready.
Preparation of Electronic Parts.
  • We have to solder the bullet connectors to the motor and ESC wires.
  • Always connect female end to the supply side.( This is a safety precaution, naked male ends will cause shorting).
  • In this step you have to solder 20 pairs (05 pair for one set of motor and ESC).
  • For doing this, take a small wooden plank and drill two or three holes on it so that the connector sits in this hole freely.
  • Heat the connector with soldering iron tip and fill solder in the connector cavity, insert the wire into solder filled cavity and remove the soldering iron, cool it by blowing air.
  • Check the soldering by pulling it apart. If the wire comes out due to dry soldering repeat the process.
  • Next level is making the PDB/ harness. Now make 4 way harness using 12 to 18 AWG wire (select the wire gauge as per the ESC rating) to connect all 4 ESCs to battery. (you can use ready made Power Distribution Board if you want) 

  • On the ESCs side of the harness use female connector and battery side male connector.
  • For converting 4 wires to single one, solder the joint firmly by applying sufficient solder and insulate the joint using heat shrink tube or insulation tape.
  • The white and red thin wires soldered to the joint is for battery monitoring connection of LCD Flight Controller.
  • If your LiPo battery came with HT60 or any other type of connector then you should connect the same type of connector to single lead end of harness.
  • Check the prepared connections for correct polarity and color coding.
  • Important - All the joints and bullet connector should be properly insulated using heat shrink tubes or good quality insulation tape.
  • Shorting of wire may cause fire, melting of wires, explosion of LiPo battery and can permanently damage your electronics.
  • Before starting actual assembly connect the prepared electronic parts together and do a testing to make sure that  all are working properly and along with this testing you can also do the ESC calibration and programming.
  • Now you can start fitting the motors and ESCs to the assembled frame.
  • Connecting the ESCs
  • I attached my ESCs directly to the frame arms using zip ties with the power wires and signal wires running towards the center plates and the motor phase wires towards the motors. 
  • I connected the red and black power wires from each ESC to red and black power wire from my power harness.
  • I connected red to red and black to black to avoid shorting and ruining the ESC.
  • I used one zip tie on each side and placed the ESC on top of the frame arm so it can be cooled by the wash of the prop.
  • Motor Phase Wires - The order in which these wires are connected determines the rotation direction of the motor and prop.
  • Depending on the motor and ESC being used the wire colors may vary.
  • Initially you can connect the three motor wires with each ESC in any order. Later, you can switch any two of the three motor wires to reverse the direction of a motor to have correct direction of rotation.

  • While attaching the Motors you should pay proper attention to reduce vibration which is the number one enemy for flight control board.
  • I used soft rubber pads made out of cycle tubes as vibration dampener under the motor mounting.
  • Motor and propeller adapter should be well balanced, never use motors which are damaged or having bend shaft.



  • I arranged the power harness between the two center plates and inside the round cavity of four way spliter.
  • Connection wires for battery coming through the bottom center plate where my battery can easily connect to it when attached.
  • ESC wires are routed to bottom side through the holes made on top center plate , ESCs and secured to the arm with zip ties.

  • Next I attached the flight control board on the top plate.
  • I attached the KK2.1.5 flight controller to the top plate using the soft casing that came with the board. This will act as a vibration damper.
  • And then a cover for the protection of Flt Control board ( This protection case can be made out of any light weight food pack or plastic box).


  • Some of the things in the center can range from the ESC or ESc wires, RC reciever, control board, and the battery.
  • The center plate size and design all depends on how you want to space out and arrange your aircraft.
  • For my design I used Velcro on the bottom plate to hold the battery attached to the frame.
  • Be sure to have some gap between frame and plates when you attach the top and bottom center plate of the quad to the arms to accommodate all the wires..
  • You can use spacers made out of any thin plastic tube (I used empty sketch pen shells to make spacers).
  • After proper arranging of all the wires, attach the top and bottom plates to the frame, use spacers to maintain required gap.

  • Battery Elimination Circuit(BEC) & Signal Connector.
  • Connect the BEC power and signal wires to the flight control board as per the sequence mentioned for X or + configuration.
  • I selected the X configuration.
  • For each motor, I connected the ESC BEC/Signal connector to its matching flight control board connector.
  • You can see from the picture below  that my ESC BEC/Signal wires are Black , Red and White. 
  • Black is the ground, red is power, and white is the signal wire.
  • Many other ESC BEC/Signal wires are broen, red, and orange where brown is the ground, red is power and orange is the signal wire.
  • Most flight control board manuals suggest only connecting one BEC power wires from one ESC to the flight control board.
  • A board only needs one power source and multiple power and ground wires can cause problems.
  • The easy fix for this is to just remove the power wire of 3 other ESC at the connector end and insulate it.
  • The KK2.1.5 is unique in that only the first motor connection supplies power to the board. So, it should not be a problem if all of the ESCs power and ground wires are connected.


  • Attaching & Connecting the Receiver
  • I attached the receiver to the front of top center plate using some double sided foam tape.
  • I used receiver connection leads to connect the receiver to the flight controller.
  • The Avionic 6 channel TX/RX connector labels mean the following:
             CH1 = Aileron
             CH2 = Elevator
             CH3 = Throttle
             CH4 = Rudder
             CH5 = Aux 1
             CH6 = Aux2
  • Each connector has three pins. One for the signal, one for power and one for a ground.
  • The pins on the inside are the signals, the middle pins are for power and the outer pins are the grounds.
  • The receiver gets its power from the flight control board and only needs one power and ground wire connected.
  • You can see I connected all three pins on the aileron channel to provide power to the receiver. Since the other channels only need to carry a signal, I used single connector to connect the signal pins of the elevator, throttle, and rudder.
  • Finally, I placed the cover over top center plate. It fits nicely, protecting the flight control board.

  • Securing the Props
  • This X configuration quad copter requires two clockwise(CW) rotating props and two counter-clockwise(CCW) rotating props.
  • I attached the props to the motors using the collect type prop adapters that came with the motors as pictured above.
  • I used one of the plastic adapter rings that came with the props to match the size of the collect adapter.
  • The plastic ring fits inside the center of the prop. After placing the prop onto the collect adapter, I tightened it down with the bullet shaped nut.
  • Now you completed the build part of your Quad Copter.
  • This is not so heavy and easy to fly, low cost and rigid.
  • Also, it has a nice landing gear and protective cover for the electronics.
  • It is very stable and fun to fly around, but it is not a super lightweight frame designed to do acrobatic flying.
  • To do more serious heavy lifting would involve spending more money on bigger low kv motors, bigger stronger props, more sophisticated flight controllers and radios and a more stronger frame, Of course, it could be upgraded.
  • Additional Facilities.
  • Now that you have finished your quad build you can feel free to add whatever you want to it. 
  • Maybe, a camera, LEDs, speakers, anything that you can carry and want to fly!
  • Add-on weight should not be too much so that your flight time reduces or will become difficult to maneuver.
Next : Step 3
  1. Setting up and Turning The KK 2.1.5 LCD Flight Controller.
  2. Flight Testing.