What makes a drone fly?

The drone you have is a very high tech piece of kit, even if you have a very cheap one!

Flight controller board

You have a controller and a drone, and the input from the sticks make the drone move. Easy right?
But inside the casing of your drone is a very intelligent flightboard (mainboard or “Flight Controller”)
This board makes it possible to fly your drone with just input from the 2 sticks.

There are sensors connected to this board, and the flight controller translates all the data from these sensors to give a smooth flying experience.

See it as your computer. keyboard and mouse are connected to it, and the computer translates the signals from them to a language that the computer understands, so you can control your computer and give it tasks.

The flight controller does exactly the same.
Inputs from GPS, Accelerometer and compass are translated, and are used to control the drone.

Flight Controllers even have processors. Most drones have either 8 bit or 32 bit processors. 8 bit technique is a bit outdated, but it is still used.

The flight controller is getting information from a lot of sensors, but what do theses sensors do?

The most important, and the ones you see in every drone are the accelerometer and gyroscope.
No matter what drone you have, it will not fly without!

Accelerometer:
The (3D) accelerometer measures acceleration (forward or sideways).

Gyroscope:
The gyroscope detects rotational movements.
gyroscopes instantly detect changes in the position, and compensate for it. It re-adjusts hundreds of times per second. that’s why a drone can hover in place.
A gyroscope measures:

Roll: rotation around the front-to-back axis
Pitch: rotation around the side-to-side axis
Yaw: rotation around the vertical axis

When these 2 sensors are combined the drone can “see” at what angle it flies, and make corrections if needed. that’s why you often read 6-axis gyro

If the drone is getting input to move forward the drone knows that, and will not correct that. but if you are hovering to take a picture, and the wind pushes the drone under an angle the drone will correct that to stay level, since there is no user input to put it under an angle.

Even a $12,- drone has a 6-axis gyro

You could even throw your drone in the air, and apply throttle,the 6-axis gyro will detect the position, even when it is upside down, and correct accordingly to get level.

Besides the gyro, you can have many other sensors as well.

Barometer:
If you have a drone with altitude hold, it will have a air pressure sensor, or barometer as well.
These sensors are getting more and more common on cheaper drones.

The barometer is a very sensitive sensor, and is able to measure your drones altitude by air pressure. when you have this sensor on your drone you can let go of the sticks, and the drone stays at it’s current altitude. this is very handy if you want to make pictures.


Compass:

Compass module

A compass is used so that the drone knows it’s heading. A compass can help fly the drone facing the same direction.
Since the drone knows where the front is pointing to you can fly it forward without losing this heading.
This information is displayed on the controller most of the times, and it can also help you “see” the front and back when the drone is at a higher altitude and you cannot see this from the navigation lights.

GPS:


More and more affordable drones are getting quipped with GPS.
GPS makes flying a drone easy, and is almost essential if you are using, or planning to use your drone for aerial footage recording.
GPS can keep the drone in a stable position since it knows it’s exact location.
The information for this location is provided by satellites, and is very accurate.
GPS can work on gps, glonass and beidou, or even a combination of these for very accurate positioning.

These are the most common sensors on drones, and depending on your make or model you can have a selection of these sensors, or all of them.

As said, the flight controller uses all this information to give you a smooth flying experience, and allows you to create the most stunning footage using GPS hold, or do crazy aerobatics depending you you gyro only.

A lot of drones also display all information from the sensors on your controller so you know exactly what is going on with your drone. You can see how high it is, how far it is from the point of take off, where the front is, how fast it is moving and so on.

Controller shows 12 satellites and 235m altitude

 

Controller showing maximum speed, travelled distance, highest altitude and current GPS location