How to build a quadcopter – Part II
In the first part of this tutorial I described which are the needed parts to build a quadcopter. Here I will try to explain the building process as simple as possible.
Start with assembling your frame. Usually an assembly manual is included or you can download it. When you are ready with this step, then you should mount all four motors on the frame. Most of the motors for the 250mm and 350mm class quadcopters use M3 screws.
On the next step, you will need to connect the four ESCs with the motors. Every ESC has on the one side three cables (usually red, black and yellow) and on the other side two cables (red and black). There is also a tiny cable which ends with a servo plug. Please note that there are ESC, that don’t have any gold connectors on its cables. In this case you will need to solder the ESCs cables directly to the motors.
Note: On two of the ESCs (either Nr.1 and Nr.3, or Nr. 2 and Nr. 4) you should reverse the red and yellow cables. This is because two of the motors should spin counter clockwise. Same is valid for the propellers. I had the problem as a beginner that, I haven’t mounted the right propeller to the right motor and so my quadcopter either not take off or flipped. So take you time, check my illustration below and mount them right.
Next you should connect the tiny servo cable from each ESC to your flight controller. The order of connecting is different for every controller. For example: On the KK2.1 the cable from the front left ESC connects to PIN1, front right ESC connects to PIN2, bottom right ESC connects to PIN3 and bottom left ESC connects to PIN4. The tiny cables on each servo wire must have this order from left to right: yellow, red, brown.
Then you should connect the power cables of each ESC to the battery. Connect all four ESC red cables to the battery red cable and all four black cables black one. There are basically two ways to accomplish this: Either you use a power distribution board and solder the cables to that one or you use a power breakout cable for connecting all the cables.
Once you have done this, you need to connect the receiver (RX) to the flight controller. The receiver pins on the flight controller differ for every model. For example on the KK2.1 controller the receiver pins are on the left side. Connect the cables from the right to the left as follow: yellow (signal), red (5V), brown (ground). To test if all cables are connected right, go to the “Receiver Screen” on your KK2.1 board. Move the transmitter sticks and check if your movements are indicated properly.
In order to make your first fly you need to “ARM” the quadcopter. Move the Throttle-Stick to the down right side, hold it for a few seconds and then release it. The KK2.1 controller should indicate “Armed”. To start the motors move your throttle stick up very slowly. If you have any problems like not taking off or flipping, “Disarm” your copter by moving the throttle stick to the down left side for a few seconds and check everything is right connected. KK2.1 will show the “Safe” screen. If you can’t solve the problem leave me a comment.