Additional information and tutorials
During this build, I have learned a ton of stuff that is not limited to just quadcopters. In this section, I will be sharing helpful video tutorials and my personal comments on soldering and building the quadcopter.
Propeller Tips
Tip #1
Tip #2
I think Terry said it perfectly. If the motor spins in a clock wise direction, you need to throw on a clock wise propeller and secure it with a cap that screws in the counterclockwise direction. The direction that the propeller spins should always be the opposite to the direction that the cap screws on.
http://www.droneybee.com/balancing-propellers/
The link above is a great tutorial on how to balance props if you use the prop balancer on the material list. Remember though, you could also balancer the propeller with the software.
Soldering Tutorials
Tip #3
Tip #4
Tip #5
Tip #6
Below is a couple of great soldering videos that are very useful for some of the harder connections you might have to make.
If you have never soldered before, I think this video is a great place to start.
If you buy the power distribution board, soldering on the through holes will be tricky and difficult. If you are going to solder the connector directly on, refer to this video. If you choose to solder on the XT60 connector via a wire, there are several important tricks to consider. Be patient while doing this solder because it will take a long time and if solder gets in-between the negative and positive connections, then the PDB will short circuit and catch on fire. In order to solder on the through holes, you need to add solder to the end of the wires first in order to make them thicker in diameter. The issue that I add when doing this is that when I was adding solder it just dripped town to the underside of the wire and formed a hanging bubble there. And that doesn't really help us because all of the solder is in a lump in one place. What I recommend is to add solder (which role down to the underside of the wire) and don't put too much where it forms a gigantic bubble of solder. Let that cool. Then place solder wire on top of the wire and QUICKLY drop solder onto the top of the wire so it is nice and rotund; it has to be quick because if the rest of the solder heats up, it will just drip to the bottom of the wire again. Here is the link to soldering cables into the through holes.
If you use a PDB, this video right here is a great visual on how to do so. Make sure to check it out! Also, make sure your connections are secure by tugging hard at the wires. If they detach from the solder, then you had a bad connection.
Interfacing
Here are a few links to some tutorials on interfacing components with the Arduino. If you are not interested in the code behind everything, skip this section. The final code that I uploaded included all of this. If you want to write your own code, these links could be useful.
Interfacing the Gyroscope + Accelerometer:
https://maker.pro/arduino/tutorial/how-to-interface-arduino-and-the-mpu-6050-sensor
http://www.instructables.com/id/Accelerometer-Gyro-Tutorial/
Interfacing the Transmitter:
http://ryanboland.com/blog/reading-rc-receiver-values/
Although this person was doing this a RC car, listening to explain how the system works and going through the code was very helpful for me. I recommend checking these out:
https://www.youtube.com/watch?v=u0Ft8SB3pkw
https://www.youtube.com/watch?v=Bx0y1qyLHQ4
Another great setup similar to a drone with explanation of code:
https://www.youtube.com/watch?v=TD2IGwq-WaQ
Tip #7
Power Systems
Great tutorial for understanding how you need to wire the power system on the drone. This can be done with a power distribution board or without one.