One thing I've been interested in for a long time has been building my own quadcopter. Everything about them is extremely interesting to me, but there's a lot of research that goes into this. Most people recommend building your own first, saying that you'll understand them better, it'll cost less than the higher end, off the shelf models, and when you crash it (and you will crash it I'm told), you won't feel as bad because of the price.
So I set off on a mission, build a quadcopter and document EVERYTHING. After reaching out to some very awesome companies, I found sponsorships to make a project like this possible, and I wanted to take a moment now to give a special thanks to all of them for their contributions!
There are a lot of components to get you flight ready, and there are even more to extend the capability of your copter.
Getting Flight Ready
The Frame: This is where everything is built around. It will determine how many motors you can mount and can make a real difference in what components you can mount. Larger frames weigh more, but they allow you to mount larger components or more of them, while smaller frames let you keep things light and simple. Depending on what you're looking to do with your multicopter should determine what size frame you're looking for.
Most people recommend you start small, and if you dig around enough, you'll even find a lot of DIY frames that people put together themselves, keeping things more affordable. Additionally, you can also buy frame kits, or complete builds.
The Flight Controller: This is the brain of the copter. Everything comes through here, this is where your motors are ultimately controlled, if you have a GPS module, it all passes through the flight controllers.
These vary between different suppliers, and some of them are pretty strongly DIY focused, but flight controllers will manage all four motors at a time, keeping them sync'd to give you the movement you want. A lot of flight controllers will have ways to measure altitude as well as GPS for advanced features to keep you from drifting, holding position, or even plotting out courses.
Electronic Speed Controllers: Branching out from the flight controller, you'll have the Electronic Speed Controllers (ESCs). You need one of these for each motor. These are a translator between your flight controller and your motors. They control the power and make sure they're spinning just like they should be so that your copter can move the way it should be.
For multicopters, these become especially important because you need very high response times on the controls for them since you have more than one motor.
Who is SimonK and why do so many people care about his ESC firmware? First we need a quick look at ESCs, which aren't made solely for multicopters. So we need a very simplified and highly responsive controller for our motors, because having all four motors working seemlessly in sync with each other is very important. Most ESCs will hit these speed marks, but SimonK ESCs have earned a nice reputation for their firmware improving refresh rates, which improves response times.
Motors: You'll need four of these for your quadcopter. Motors in general should be self-explanatory, they spin your props. Where things can get complicated is decoding what kv is, what's right, and how many amps you'll want.
Kv can be misunderstood for a power level, but it is actually the number of times the motor can make a revolution in one minute per volt.
Propellers: These are exactly what you think they are. These will push the air to give you lift. They're typically measured in overall width and pitch. A 10x45 propeller has a total length of 10 inches and pitch of 4.5.
Radio Transmitter and receiver: These are the main pieces that you'll have to live with for a long time, and the ones you can't upgrade, so you'll want to really plan this one right. Your radio will control everything, your motors, and if you plan to have additional features such as a camera on a gimbal, or any GPS features. Most people will recommend starting out with nothing less than a 6 channel radio setup. From the radio you'll have a transmitter with an antenna on the back. Then on your quadcopter you'll have a receiver, which will connect directly to your flight controller, and each channel will be configured from here.
Batteries: There's a lot of confusion for such a simple component. The short and simple answer, the battery supplies electricity to everything. That being said, there is a lot of different information on performance and ratings. So here we go...
LiPo - Stands for Lithium Polymer and is a rechargeable battery. They've been able to fall into the RC world because they are light weight, can be made to nearly any shape or size, can have high capacities for small units, and have high discharge rates, making them ideal for electric motors.
2S, 3S, 4S, etc - S stands for the number of cells in a Series. All cells are rated for 3.7volts, but by connecting them in series, they can obtain a higher voltage.
- 3.7 volt battery = 1 cell x 3.7 volts (1S)
- 7.4 volt battery = 2 cells x 3.7 volts (2S)
- 11.1 volt battery = 3 cells x 3.7 volts (3S)
- 14.8 volt battery = 4 cells x 3.7 volts (4S)
- 18.5 volt battery = 5 cells x 3.7 volts (5S)
- 22.2 volt battery = 6 cells x 3.7 volts (6S)
mAh - milliamp hours, is the amount of power a batter can give before it is drained for an hour. If a battery was rated for 1000 mAh, and had a 1000 milliamp load placed on it, it would take one hour to drain the battery. If a 15 amp load was placed on it (15,000 milliamp), and you had a 4200 mAh battery, you would get just under 17 minutes minutes.
Going Beyond Flight Ready
Battery Monitor: This is one very affordable component that is highly recommended. These typically connect directly to the battery, alerting you when the battery is at various low levels, helping you avoid crashing due to a drained battery.
Gimbal: Used to mount cameras, basic gimbals just mount a camera in a fixed direction. You can also fin Brushless Gimbals that typically have two or three motors, to let another person move a camera around, giving them a first person perspective or focus in on something specific. These vary in size and builds for smaller cameras such as a GoPro, to larger builds for DSLRs.
Video Transmitter: This is just as it sounds, it transmits video. There are many needs and uses for multi-copters, transmitting video to let people on the ground view a video feed or record an aerial session is another extremely useful ability. You will need a transmitter and a receiver for something like this, and transmitters will vary in strength.
FPV Camera: First Person View Cameras, are small cameras, with typically lower quality than you'd want for recording purposes, but are ideal candidates for allowing someone to see close up what the multi-copter sees, allowing as they're called, a first person view.
Video Goggles: These give the true first person experience, as you can see exactly everything your multi-copter can see. More elaborate setups can track your head movements and control a gimbal holding a camera, have video receivers built into them, and have additional video out ports.
If you have any other questions on components I may have left out or didn't explain thoroughly enough, please don't hesitate to let me know and I can make sure everything is covered.
I'd also like to take a moment to thank our sponsors again, as well as some brave volunteers who wanted to help contribute to this project with photos of their own builds.