There are a few types of motors that are use to build drones. But as the drone needs to be thrust in the air to float, we should use some powerful motors. The cheap, lightweight, small, and powerful motors used in drones are Brushless DC motors (BLDC). For small drones, we do not use BLDC motors, but instead use small DC gear motors.

You cannot control the speed of motors of your drone unless you use speed controllers. They enable you to control the voltage and current of the motors and hence control the speed, which is the first priority to move the drone one place to another, after floating in the air. You need to increase and decrease the speed of motor(s) to move the drone forward, backward, left, or right.

The connection between the controller board of the drone and ESC and the battery/power distribution board will be shown in Chapter 2, Assembling Your Drone:

Refer to the following circuit diagram:

This is one of the most important things to control the drone from the ground. There are a number of flight control boards on the market. Some of them are open source and some of them are not. The following list has the most famous and top-rated flight controllers:

• KK 2.0
• CC3D
• Naze32
• KISS
• ArduPilot
• Vector
• 3DR Pixhawk
• DJI Nava M
• LUX flight controller
• DJI A3

In this book, we will use ArduPilot, as it is cheap and it is best for copters. It also covers our book title. The following picture of some flight controllers.

The ArduPilot is one of the best flight controllers for drones because of the following reasons:

• It has a free, open source autopilot framework supporting different types of drones
• It supports hundreds of 3D waypoints
• It allows you to do the autonomous take-off, landing, and camera control
• It has 4 MB onboard data-logging memory
• It has a built-in hardware fail-safe processor
• It has full mission scripting
• It is really simple to set up

The following picture is an ArduPilot:

We will discuss more about the ArduPilot later.