How to Build a Drone – A Quick Guide
Drones are becoming very popular these days and its application in various industries like photography, surveillance, agriculture, delivery, defence and more are increasing day by day. Building a drone can be a very exiting project given that you know the building blocks of building a drone. In this article we will walk you through various things you need to understand before you can start your drone building journey. In this article we are taking an example of multi rotor quadcopter drone but the same can be applied to other types of drones as well. The majority of building process and components will remain same but if you are looking to build a fixed wing or a single rotor drone, I would suggest to look for a specific article on that.
How to Build a Drone – Core Components
Components required for building a drone depends upon what type of drone you want to build and its application but the core or essentials components remain same for all kind of drones. Only accessories like camera, gimbal, gps etc. varies from drone to drone. Also, depending upon the final purpose of drone you may upgrade some of the core components e.g. if you want auto-pilot you may upgrade the flight controller which supports auto-pilot. The core components required to build and fly a drone are –
- The Drone Frame
- Electronic Speed Control (ESC)
- Battery & Battery Charger
- Flight Controller
- Transmitter and Receiver
Now, let’s get into each and every core components in detail to understand their importance and usage in building a drone.
The Drone Frame
To build a drone the first and foremost component you will need is a drone frame or drone body. Drone frame holds all other components of the drone like motors, ESC, battery, flight controller and all other accessories. For this reason it is essential that a frame is as durable and rugged as possible, while still accommodating to the needs of the pilot without hindering the flying experience.
The drone frame consist of two major parts – first is the wings which holds the motor and second is the main body or mounting body where flight controller and other components are placed. Sometimes we also use a drone pod to protect main electronic components from direct exposure. The size of a frame is measured diagonally between the two extreme end where motors are placed. A frame measuring less than 150mm motor-to-motor is categorised as a micro. A frame larger than 150mm motor-to-motor is considered a mini. When measuring an unconventional multicopter frame, such as a hexacopter or tricopter, the size will always be given by the greatest motor-to-motor distance.
The another important consideration in drone frame is the material. As discussed earlier the drone frame should be durable and rugged but at the same time it should be light weight also. For this reason majority of drone frames are made using carbon fiber sheet. Carbon fiber is a composite material, being made up of many layers of interwoven carbon fibers that have been rigidly cemented within a binding matrix of epoxy. The popularity of carbon fiber as a frame material is due to its low weight and high strength. It is also important to note that carbon fiber is an electrically conductive material.
Apart from carbon fiber, drone frame are also made using HDPE (high density polyethylene). HDPE is low cost material and easily available but it is not as strong as carbon fiber, therefore designs that incorporate HDPE are typically heftier. There are many frames that use a combination of carbon fiber and another material such as aluminium or 3D printed TPU (a flexible polymer) in their construction. The use of these materials is a great way to improve the strength of a frame, better protect components or simply to add flair to a design.
Below is most popular Diatone Q450 Frame Kit. If you search for drone frame on google, you will most likely find the below one. It is built from high quality glass fiber and ultra durable polyamide nylon.
Motor is the second very crucial component of any drone. Motor has an enormous influence on the flight characteristics of the multicopter. Tiny variations in the construction of a motor result in significant impacts regarding the weight, responsiveness and total power of the multicopter. Motors used in muticopters are of the two types – brushed and brushless.
The principle behind brushless and brushed motors is very similar. When an electric current is passed through the windings of the motor, magnets distributed within the motor are attracted or repelled. The repetitive repulsion and attraction of the magnets translates into a revolution of the shaft. This allows the motor to spin an attached propeller at extremely high speeds, in turn, producing thrust.
Brushless motors are typically more efficient around 80-90% whereas brushed DC motors are around 75-80% efficient. This difference in efficiency means that more of the total power used by the motor is being turned into rotational force and less is being lost as heat. Another advantage of brushless motor is, it has a lower susceptibility to mechanical wear than their brushed counterparts. Brushless motors also provides: Higher torque to weight ratio. Increased torque per watt of power input (thus increased efficiency).
Thrust is one important factor to consider while selecting the right motor for your drone. Motor should generate enough thrust to overcome drag and pull of gravity to make your down fly upwards. The thrust output of a motor is usually measured in grams and varies depending on how fast the motor is spinning and the propeller that it is rotating.
We will discuss more on this in future articles on the principle behind flying and how drone flies. Now let’s move on to our next components in the list.
Electronic Speed Control (ESC)
Every (brushless) motor in your drone needs an ESC or electronic speed control circuit for its operations. ESC circuit controls the motor speed, its direction and also used for breaking. When we use RC remote to accelerate the drone, hover, move forward or backward, all the command from RC remote goes to the flight controller and then to the ESC. ESC takes the command from flight controller and power from battery and makes the motor spin accordingly.
ESC also converts the DC current from battery to the a 3 phase AC current needed from brushless motors to work. Quadcopters and other drones depend entirely on the variable speed of the motors driving the propellers. This wide variation and RPM thrust and control in motor/ propeller speed gives the quadcopter all of the necessary control to fly. For every motor in your drone you will require an ESC circuit.
When it comes to propellers, many drone makers pay less attention to it but believe me this is another very crucial component of your drone. Propellers converts the motor rotation into thrust which takes your drone fly and move in the air. A good analogy would be the tires on your car and tires are the one which makes your car move on the road and breaks when needed. The size, design (efficiency), pitch (angle of blade), blade and material (durability) of propeller need to be considered while buying propellers for your multirotor.
They are also going to be the component that is damaged and replaced the most often. Taking time to choose the right propeller for your multirotor, and how you want to fly, will allow you to get the best out of your machine. Propellers are commonly described by its size, pitch, and blade configuration written on the its specifications. For instance, you may see a propeller being described as a 5×4.3×3, the first number corresponds to the size, 5 inches in this case. The second to the pitch, 4.3 inches in this case. And the third to the number of blades, which in this case would be a 3 bladed propeller.
Size (in inches) X pitch (in inches) X number of blades
Battery & Battery Charger
Drones are power hungry machine. In quadcopter, 4 high speed motors requires constant power to drive propellers at tens of thousands of revolutions per minute (RPM) and generate enough thrust to fly against gravity. Drones can operate at various voltage level depending upon its size e.g. from 4.5V for micro-drone to 25V high power quadcopter. But drones requires heavy amperage to generate high power. In a decent size FPV quadcopter drone, each motor draws nearly 25 amps of power, multiply that by 4 motors, you will need 100 amps power supply from battery to feed the hunger of your drone.
Such power comes from a special battery built specifically for this purpose. Currently, the battery of choice is the lithium polymer battery, called a “LiPo.” These batteries can deliver a hefty current to match the demands of the motors, are small enough to fit on the drone, and are energy-dense enough to give us minutes of flight time. These are also re-chargeable batteries so it can be re-used multiple times. And, also needs a special fast chargers to charge them quickly for the next flight.
When it comes to battery charger, you will need a smart charger for your various needs. The charger should be able to not only fast charge your main drone battery but it should also have option to charge other batteries you will be using like transmitter and receiver batteries, google batteries and other such upgrades you might be using.
Most battery chargers available for drone market uses microprocessor controlled circuitry, it monitor the conditions of the battery to vary voltage and current throughout the charge to optimize charging and prevent damage to the LiPo battery. Most modern drone battery chargers are capable of charging at a variety of different voltage. Goggle batteries for example may require 8.4v while drone batteries may require 16.8 v and above. Drone battery chargers should very easily be able to charge at a variety of user-selectable voltages. That way a single charger would be sufficient for all the needs.
Flight controller is the most interesting component in your drone. It is the brain of your machine analogous to the motherboard of your computer. It connects all the electrical and electro-mechanical components of your drone and makes it intelligent and adds super powers to it. Flight controller takes information from IMU (Inertial Measurement Unit), Gyroscope, GPS modules, obstacle detection sensors etc. if on the quadcopter. It makes computation calculations using programmed flight parameters and algorithms, then sends this data to the electronic speed controllers.
Flight controller can be as basic as only IMU and takes command from your RC remote or it can be as advance as having gyroscope, GPS module, obstacle sensor, rain sensor, camera and gimbal controller etc on it and can make your drone completely auto-pilot. Depending upon your requirement, you can decide which flight controller suits best for your need. You can either build your own flight controller or take any controller readily built and available in the market. For a quick prototype it is always recommended that you start with an already available flight controller and upgrade based on how your requirements changes over time.
Flight controller is programmed with a firmware that configures the board with the program and settings required to manage and control the quadcopter. There are proprietary as well as open source firmwares available for your flight controller e.g. DJI Naza flight controller has its own proprietary and closed source hardware and firmware but other flight controller like pixhack uses a ArduPilot firmware which is open source.
We will discuss more on flight controller in future articles covering basic to advance flight controllers and auto-pilot softwares. It is important for you to understand that flight controllers are very powerful components of your drone. In your drone building journey, you will keep upgrading your flight controller to bring more and more power to your flying machine.
Transmitter and Receiver
The final component you will need to fly and control your drone is a transmitter / receiver pair. You would have seen drone pilots using a remote to fly drone. The RC remote contains a transmitter / receiver pair to pass commands from your remote to drone flight controller and receives status back from drone. Your drone also has a transmitter / receiver pair to receive signals from your remote and sends the status back.
A basic manual RC remote helps you send and receive commands and status of drone vs in an auto-pilot system, your drone will have GPS and compass and you can define the way point for navigation. In advance control systems you will also have a on-screen display to see your drone status or you can also connect it to your mobile phone via USB and can control the drones from your phone.
If you are using a camera on your drone to take live video feed or picture, you will use an additional transmitter for sending video stream to your ground controller. Your ground controller can be a simple receiver and display to show you the video feed or it can more advance like FPV goggles which you can wear on your head to see in realtime your drone video feed.
Above listed components are the basic need for any drone. Now depending upon your requirement you can build a basic manual drone for flying or more advance drone which has auto-pilot and can fly on way point to do land survey or generate NDVI map for agriculture land. Your imagination will be the end of what all you can do with your drone and thus you will learn and use various components intelligently.
Stay tuned for more guides on Drone!
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