The flying drone industry is taking off. The hobby is growing into an industry. Building a hobby drone is this post but building Mission Planner Ardupilot commanded ships is our Business
Why are you interested in Drone Technology and what will be your level of involvement? As you will see there are multiple avenues you can take and cost will be a big factor.
If learning Technology is your objective then building your own unit is the route and indeed you will learn many aspects of design as well as many scientific disciplines.
If flying is your objective because of a interest in video or aerial photos then there are many options to purchase RTF (ready to fly) systems tailored to your specific needs.
If racing is your interest then there are additional requirements also , just as the other specialty builds. Building your own in this category is almost a requirement to be competitive. Yet the intensity of this is extreme. Especially the small class drones, building with small parts, wiring and soldering super small components and the selection and compatibility of all the components.
Building a drone gives you the flexibility to choose the parts, you get better information understanding and when you fly you realize the changes to flight characteristics based on the new component
Choosing a RTF drone is easier to budget and the costs are more apparent. Just look at the entry model and then the maxed out one to get an idea of where you are heading.
Our objective is to separate the two builds as classes so entry level can be achieved rather cheep and still be a competitive sport.
CHOOSING A FRAME FOR YOUR DRONE
Drone frame types we are building
QuadCopter – 4 Motors Multicopter
This type of quadcopter design is easily the most common among builders. As its name suggests it has four motors attached to four arms in a symmetrical configuration however the forward direction varies, the most typical direction put it between two arms resulting in what’s called an X configuration. Another option is to have the forward direction along on of the axis’s making it a + configuration.
For a beginner this is the configuration to choose. It is easy to control and very stable mid flight and almost all controllers are built with this configuration in mind because of its versatility and ability to adapt to any drones usage you might think of as demonstrated by all the popular designs from the likes of DJI and Parrot.
Eight motors connected to eight arms, this makes for a very powerful drone capable of lifting quite a big payload. But as you would imagine this all means more parts, more weight, more batteries and more costs.
X8– 8 Motors Multicopter
Hybrid design, based on the typical quadcopter but with eight motors mounted on 4 arms. This is similar to concept to the Y6 configuration discussed above but with the added arm and motors.
Bad: expensive option to build and fly
MOTORS, PROPELLERS, AND PROPULSION
Now that you have decided what your end goal would be in regards to the drone you are building and have chosen a frame accordingly, the next step in building your own drone is to think about how we will get it to fly!
This part is called the propulsion system, and is composed of motors, propellers, ESCs, and battery.
This is the part that moves the propellers to generate thrust and lifting power to get the drone airborne and control its altitude and direction. First thing to consider is that you need identical motors to be mounted on your drone for stability. But despite this even identical motors’ speed might vary a bit, this is where the flight controller comes in to balance stuff.
We are not going to get into the details of electrical motors and engineering because we don’t need to build a motor, only know how to choose the right one. And in this regard there are two options to choose from, either a brushed motor or a brushless motor.
Another important factor you need to consider when choosing a motor for your drone build is thrust. This is usually supplied by the manufacturers in a table indicating the amount of thrust (indicated in Kg, Lbs., or N) per propeller size. How can you use this data?
Let’s say a motor spec is 0.5KG with a 10” propeller. This means if you are building a quadcopter with 4 of this motor and using 10” props on it then the total weight of the must not exceed 2 KGs ( 4 x 0.5 Kg = 2.0 Kgs ). In this case, if your drone weighs exactly 2 Kgs then it might not even take off, so you will either need to lower its weight or get stronger motors. Always have more lifting power than the total weight of your drone.
The size of the props is indicated in either cm or inches and is measured from the furthest two points of the blades. What you need to know about this is that in general smaller blades are best for racing drones where fast reactions and required and larger blades are best suited for more stable flights like aerial photography.
Blades rotate either CW “Clock Wise” or CCW “Counter Click Wise”. You need to know which side of the propeller is meant to face upwards (the top surface is curved outward) and which is meant to face downwards. If you have chosen a configuration where there are two motors on each arm, this means that you will need to have a rotor that is on the bottom of your drone. You need to pay special attention to the way it mounts because the way that is supposed to face upward still needs to face upwards, even if it is mounted below. The documentation that came with the flight controller should show you which way each propeller is intended to turn for each multi-rotor it supports
MATERIALS USED TO MAKE PROPELLERS:
Because of its low cost and respectable durability, plastic is by far the most popular choice for propellers in the multi-rotor industry but plastic propellers do have their downsides, they are not very reliable. Incase you crash, especially if you do not have prop guards on, you are very likely to break the plastic propellers. Even with the guards on a serious crash can still break your props. They shouldn’t be a huge problem because of their low price you can easily replace them. Most commercial quads even come with several spare propellers included.
While not very common, wood is still used as a propeller in some situations because it is more sturdy than plastic but because of the way it is manufactured wood is not very common.
And finally the top of the line material to choose from propellers is carbon fiber. Carbon fiber is much stronger and more stiffer than plastic meaning it is less likely to break during a crash but it is much more expensive than plastic.
The “prop guard” is is exactly what its name suggests…a protection for your props. This will help you a lot when you crash the drone because the guards will prevent the fast rotating propellers from coming in contact with any hard surface preventing them from braking. Prop guards add weight to your drone making your flight time that much shorter but they are important to have until you really know how to fly.
THE ELECTRONIC SPEED CONTROLLER (ESC)
This electronic component links the flight controller with the motor. What it does is control the voltage and power that the motor receives and thus setting the speed that the motor spins and how much lift is generated. This is essential to be controlled for each of the drones motors which is why you will need an ESC for each motor you have on the drone.
Things to note when choosing an ESC is that it is able to handle more than the maximum current that the motor needs so that it does not burn out, also that is has the right voltage.
POWER DISTRIBUTION BOARD
Most drones have only a single battery and several motors, so the power coming from the battery needs to be split into several parts to power each ESC, this is done through the Power Distribution Board. The thing to note here is the type of connector used by the PDB and the ESC, most manufacturers use a standard connector but cheap boards don’t use connectors at all and just assume that you will solder the wires. In such case be prepared for some soldering fun.
The widely used and best performance battery for drones is Lithium Polymer (LiPo for short). Other technologies based on Lithium combinations do exist but are not very common. Although this is starting to change because of advances in the other technologies
Currently NiMh and NiCd are not widely used, but their capacity and voltages are getting better, the overall safty of these technologies is greater than LiPo so expect to see them more and more
The primary concern with LiPo batteries is handling, and this is primarily because of fire. Storage and improper charging can reduce a batteries life but burning down your house becayse one catches fire aint no laughing matter.
Batteries might be the most important component to be concerned about , this requires further study
THE FLIGHT CONTROLLER
Now that you have chosen the drones’ main parts, the frame, motors, batteries and the ESCs and other small parts it is now time to get something to join all these parts and teach them how to properly behave so you can build your own drone that actually flies. This thing is called the Flight controller.
The microprocessor is the brains of the flight controller and takes all the inputs which are usually analog in nature and translates them into digital signals to make it possible for it to tell the ESCs what they need to do to accomplish what the pilot wants to do. Basically you need to get the fastest processor that you can afford simply because of all the things that need to be calculated and controlled at a single time.
The different sensors tell the flight controller what it needs to know in order to be able to tell the ESCs what to do. These are the eyes and ears of a drone. There are several different things which can be monitored by a flight controller at a time, at a bare minimum every controller has a three axis gyroscope, other sensors discussed below are not necessarily included in all flight controllers, but of course the more the better,
Measures linear acceleration on up to three axes (X, Y, and Z). Since it measures earth’s gravity this is what tells the drone which way is up and which way is down and as such allows an RC drone to remain stable in the air.
Detects angular changes on up to three angular axes (alpha, beta, and gamma) meaning it measures how fast the drone is rotating in any axis.
Compass / Magnetometer
This measures the Earth’s magnetic field to determine the drone’s magnetic North and is needed with a GPS to determine the way the drone is facing at any point in time.
Inertia Measurement Unit (IMU)
An electronic board that combines the above sensors mostly.
A sensor that measures the atmospheric pressure around the drone. This, combined with a GPS, can give a prey accurate reading of how high above the sea level the drone actually is.
A Global Positing System that uses several satellites orbiting around the Earth to triangulate the exact 3D position of a drone. Some GPS chipsets also use GLONASS which is an equivalent system developed by Russia.
Protocols exist to transmit the signal from your controller to the drone. Mavlink the primary one
The most common method of controlling a UAV is by using Radio Control communication. This involves a handheld RC transmitter, which you hold, and a RC receiver that needs to be installed on the drone. These differ in the number of channels it uses. An absolute minimum is four channels used to control Pitch, Elevation, Yaw, and roll. Other channels can be used to control things like, on/off, gimbal controls, change of flight mode, buzzer, etc.
This is the same protocol used on your smartphone. Not very common protocol but used in some controllers nonetheless.
Some drones have a WiFi access point that allows your controller to pair with it using Adhoc mode.
This is the technology used by your TV remote control. It is not very common because it has many drawbacks, mainly of interference and more importantly because it needs line of sight to work.
BASIC ACRONYMS :
Synonymous with the term “quadcopter” or “UAV” or “UAS”. The term “drone” is usually related to military use of unmanned aerial vehicles.
UAV : unmanned aerial vehicle
UAS : Unmanned Aircraft System.
Drone Size and class:
This determines the drone’s class (mini, micro, etc.) and is given in millimeters. This is measured by the greatest distance between the two motors on the quadcopter.
CG : “Center of Gravity”, which is the point on the drone where weight is equally distributed on all. You need to know this to be able to properly balance your build.
This is the main chassis of the drone, upon which all other parts are installed and mounted.
LED : Light Emitting Diodes used for Navagation and appearance
Prop Guards :
Guards protect both the drone’s propellers from being damaged when crashing as well as to protect others incase they get hit by a drone.
SENSORS : Electronic upgrades for all types of information
Accelerometer : used to measure liner acceleration.
Barometer : sensor used to measure air pressure. This tells the drone how high above sea level it is to determine altitude.
Gyroscope : Measures angular acceleration enabling the drone to balance itself midair.
GPS : Global Positioning System receiver this receives signal from global GPS satellites to tell the drone where exactly it is located.
ESC “Electronic Speed Controller”, controls power and timing to the motor the motor
Li-Po “Lithium Polymer”, Technology used in the battery for your drone. The current standard now for making drone batteries because they store lots of power compared to their size and weight. However they can be a fire hazard so you need to handle the batteries with care.
Motor You know the motor
PCB “Printed Circuit Board”. Electronic component that has all kinds of circuits, and controllers installed or “printed” on it. These connect all your electronic parts together.
FPV “First Person View”. Goggles pay attention to this Analog and Digital
Gimbal connects the camera with the body of your drone to stabilize the camera and make sure it stays level in relation to the ground even if the drone tilts and to reduce the shaking resulting for the movement of the drone.