Update 5/28/2014 – I built this quadcopter back in 2012. Since then a lot has changed. Quadcopter kits with more capabilities are now available for a similar cost. For example, the Quanum Nova FPV GPS Waypoint QuadCopter is $269 with free shipping. It has full GPS waypoint capability and has a GoPro mount. I haven’t tried the Quanum Nova quad, but it is based on the proven APM controller.
In Part 1 of this post I selected parts needed for an inexpensive quadcopter that was easy to build, tune and fly. This post, Part 2, covers the details of putting it all together. In Part 3, I will set up the transmitter, ESCs and KK2.0 board so I can make a maiden flight. In part 4, I will show how I tuned the quad’s PI settings to optimize its flying capabilities. Finally, in Part 5 I will cover how I attached a GoPro camera to the quad to get some video from the air.
Continue reading to see the build details…
Assembling the Frame
The quadcopter frame I chose came with a diagram showing how all the individual parts fit together. It took a little bit of time to fit everything together, but for the most part I just followed the diagram. I should have assembled the landing gear and attached it to the bottom center plate of the frame first, then assembled the arms and center plates. Unfortunately, I did the arms and plates first and had to take them apart to get the landing gear attached. Also, I wanted my quad to fly in and X configuration, so I had to make sure I screwed the landing gear to the center plates correctly for that setup.
One thing I didn’t do was use the 3mm set screws to secure the arms of the landing gear as shown in the diagram. They just seemed too big. I considered using some cyanoacrylate glue to hold the landing gear together, but at this point I have just left it secured by the plastic fittings that hold the carbon rod legs together. The landing gear could be a bit beefier. I will probably get some pipe insulation to wrap around the skids to give it some cushion against hard landings.
Finally, I attached the motor mounts upside down from how they are shown in the diagram. It made more sense for the countersunk holes to be on the bottom so the motor screws would be flush against the mount.
Securing the Power HarnessI threaded the power harness between the two center plates. I left the 4mm HXT protruding through the bottom center plate where my battery can easily connect to it when attached. I ran the 3.5mm bullet connectors through the top center plate to enable connecting my ESCs and secured them with zip ties.
Attaching the MotorsAs I mentioned above, I reversed the motor mounts so the countersunk screw holes would be on the underside of the arms. I aligned the 16mm and 19mm holes in the Turnigy D2830-11 motors with the appropriate holes in the motor mount and secured them with the screws that came with the motor. I used a small amount of blue removable loctite on the screws for a more secure hold.
Securing the Props
I attached the props to the motors using the collet 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 collet adapter. The plastic ring fits inside the center of the prop. After placing the prop onto the collet adapter, I tighened it down with the bullet shaped nut.
Before doing any setup or tuning (Part 3), I removed all of the props.
The props sit a bit high on the motor shaft. I was tempted to cut the shafts down, but didn’t. I may do that as a modification at some point.
Attaching the Flight Control Board
I attached the KK2.0 flight controller to the frame using the nylon risers that came with the frame. The programming buttons are on the same side as my battery connection which is the rear of my configuration X quad.
Connecting the ESCs
I attached my ESCs directly to the frame arms using two zip ties with the power wires and BECs running towards the center plates and the motor phase wires towards the motors. 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. I placed the labeled side of the ESC down facing arm. The labelled side has a heatsink cooling and protecting the electronics. The electronics on the other side are less protected and might be damaged if tied tightly to the arm.
I connected my ESCs in three different places.
Motor Phase Wires
The order these wires are connected determines the rotation direction of the motor and prop. Depending on the ESC being used the colors may vary. I initially connected the three motor wires from each ESC to the 3 motor wires in any order. Later, I can switch any two of the three motor wires to reverse the direction of a motor and prop if necessary.
Battery Elimination Circuit(BEC) & Signal Connector
Finally, I connected the BEC power and signal wires to the flight control board. Most flight control board manuals suggest only connecting the 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 and place heatshrink around all but one ESC power and ground wires.
The KK2.0 is unique in that only the first motor connection supplies power to the board. So, it is not a problem if all of the ESCs power and ground wires are connected and I didn’t remove any of the BEC power and ground wires. For each motor, I connected the ESC BEC/Signal connector to its matching flight control board connector.
You can see from the picture above that my ESC BEC/Signal wires are brown, red and orange. Brown is the ground, red is power, and orange is the signal wire. Many other ESC BEC/Signal wires are black, red, and white where black is the ground, red is power and white is the signal wire.
Attaching & Connecting the Receiver
I attached the reciever to the front of top center plate using some double sided foam tape.
- CH1 = Aileron
- CH2 = Elevator
- CH3 = Throttle
- CH4 = Rudder
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 with one servo lead to provide power to the receiver. Since the other channels only need to carry a signal, I used another servo connector to connect the signal pins of the elevator, throttle, and rudder.
Finally, I placed the cover over arms and center plates. It fits nicely, protecting the flight control board and receiver. I secured it with the included knobs and cotter pins. I also made an easy DIY mount to attach my GoPro housing to this frame that I will cover in Part 4.
Note: I wanted to use the Multistar ESCs since they already have bullet connectors and fit my plan for a super easy build, but could only get one ESC before they sold out. Until I can get my hands on 3 more Multistars, I used another brand of 25amp ESCs that are very similar to the Turnigy 30amp Plush ESCs that I listed as an alternative in the parts list. They use the same programming card. Even though the motor listing says to use 30 amp ESCs it also says the max current for the motor is 21 amps. Also, you can see on this listing for the Turnigy 25amp Plush ESC that they can handle a burst current of 35 amps. The Multistars come with 3.5mm bullet connectors already soldered on. All the other ESCs I have mentioned come without bullet connectors which have to be ordered separately and soldered on.