Drones, also known as unmanned aerial vehicles, were originally developed for military purposes. These are aerial vehicles without a pilot, which are controlled either from ground using radio controllers or are programmed for autonomous flights. Now, besides military action, drones are being built for various kinds of applications that are usually boring, routine or too dangerous for human beings.
Just like aero modelling, flying drones can be a great fun. However, their use is restricted by law in most countries. So before buying a drone, do check the law pertaining to use of drones in your region.
Fortunately, many small-size drones are now available in the market to experiment with. But because of their large variety and variance in size, it can be confusing to select the one most appropriate for you. Hope the hints below will be of some help to you.
Types of drones
Most drones are designed for specific purposes. There are drones that do anything from home delivery, photography, videography, racing or surveillance. Based on their functionality and build these can be divided into three main types:
1. Ready-to-fly drones that come fully equipped but require a clear fly zone and enough battery power to fly.
2. Bind and fly drones that do not come with a receiver. The compatible transmitter is brought in by you.
3. Almost ready-to-fly drones for DIY enthusiasts.
Drones meant for DIY enthusiasts generally have four or six propellers with separate motor for each. The motors and the propellers have to be exactly identical for a proper lift-off and movement in the air.
Bigger drones use brushless motors while the smaller ones use brush motors. These differ in architecture as brushless motors have spinning magnets instead of spinning coils.
Brushless motors can deliver more torque and are longer lasting that the brushed ones. For a stable flight, everything including the motor and speed controller must work in unison.
What to look out for
Carbon fibre is one of the most desirable materials for the frame. It is lightweight and strong. Other materials are titanium, aluminium and steel. However, metals are heavy as compared to fibreglass and other polycarbonate materials. Apart from carbon fibre, Balsa wood frame is also light, tough and cost-effective.
Sensors. Almost all drones come with an accelerometer for measuring linear acceleration. It allows a radio-controlled drone to remain stable in the air with the help of a gyroscope that detects angular changes. There is also an inertia measurement unit, which is a small board that houses the gyroscope and accelerometer.
Higher-end drones also include a compass, barometer or GPS.
Battery life. Lithium-polymer rechargeable batteries power almost all drones. These are lightweight and pack a lot of power. These need to be charged regularly and also need to be handled cautiously.
Smartphone connectivity. Most commercial drones come with their proprietary remote controllers. Only some give you the freedom to connect to a smartphone in case you forget the controller at home. Make sure that your phone is compatible and syncs with the requirements for flying the drone in virtual mode. Some drones are also Wi-Fi-compatible and come with a setting to switch and select connectivity options within their respective mobile applications.
Camera. The need for a higher-resolution camera mounted on the drone gradually increases as you shift from being a beginner to a professional. At the entry level, a 2MP HD camera with 4K resolution is a good enough option. However, it is the gimbal and anti-shake features that determine stability of the footage. Gimbals come in 3- and 2-axis, and 3-axis does a better job of filmmaking and photography.
First-person vision. This is simply video plotting on a screen that is used to pilot drones. Some drones have a screen mounted on the remote control. Head-mounted first-person vision can give you a more immersive experience of piloting a drone, but it can be expensive.
Major drones in the market
Beginner-level drones. Blade Pico drones are equipped with a sensor called sensor-assisted flight envelope (SAFE), which helps it understand if the flight attained is stable, and if not, it stabilises itself. For beginners, this is a great buy as the drone does not spin off and crash. It works at 2.4GHz frequency, has a 6-axis gyro and weighs about 200 grams with a sustainable flight of seven minutes.
Drones from Hubsan have durable build and come with detachable propeller guards to protect the propellers from breaking in case of crash. These come with one-click flip in forward and backward directions; these level themselves in mid-flight, if these sense no human control. These weigh around 340 grams—a little heavier than Blade—while giving up to nine minutes of flight and a control distance of over 100 metres.
Intermediate-level drones. Drones from UDI are designed to be wind-resistant so that these can work in rough outdoor conditions. Falling under intermediate segment, a UDI drone houses an HD camera of up to 720-pixel resolution for better visual recordings and a microSD card slot. It comes with an LCD display that shows the vitals of the drone such as battery power for sustained flight, areas for safe landings and one-key return to bring the drone back to its original take-off site.
With cameras capable of delivering up to 1080-pixel video quality, Syma drone would be a winner in terms of cost and agility. Its frame is sturdy and light, giving 10 to 12 minutes of flight time for extended videography or photography. Capture videos in a 360-degree eversion (inside-out movement) and all you will see is key metrics on the LCD screen.
Professional-level drones. Drones from Parrot can be regarded as ariel gymnasts. Parrots are designed for speed, and almost all drones in the segment are fast enough to handle speeds up to 18 kilometres an hour. These link up easily to Android or IOS smartdevices. Pressure sensors and altimeters, in addition to ultrasound sensors and accelerometers, are integrated for evaluating safer zones to fly in their flight path. These have far greater flash memory storage. Applications to control the drones are immersive enough to ignore the remote control.
If you want a drone with vision sensors, a long range of about 4.3 kilometres, real-time first-person vision on the smartphone, virtual joystick, satellites connectivity for location locking and auto-return by itself, your search would end with a futuristically-designed drone from UTI. This drone, small enough to fit in your backpack or pocket, demonstrates intelligent flight modes once you unwrap it and switch it on.
Perfect for hi-definition videography, the UTI drone has flow-mode setting that automatically locks on the object it is looking at and follows it intelligently through an ascend or descend, while it captures vision in 2.7k resolution. With a control distance of one kilometre, this is one drone that packs the punch.
Shanosh Kumar is technology journalist at EFY. He is BCA from Bangalore University and MBA from Christ University, Bengaluru