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.