While most quadcopters come with their own controller there may be a reason why you need to look into a new or better flight controller. Maybe you desire to do more complex things with your quadcopter that the stock controller cannot handle. Maybe the stock controller simply quit working and you need to replace it. Understanding what these controllers do, how they work and how they will “talk” to your quadcopter is important so that you can select the right one.
The flight controller – abbreviated as FC – is pretty much the brains of your quadcopter and works everything you do with it. Basically, it’s just a circuit board that takes your commands and sensor date it received and tells the quadcopter motors what to do in order to stay in the air at certain altitudes, when to come back to you, and more. There are so many of these flight controllers on the market that wading through them all is time-consuming so we are going to give you a run-down of some of the most popular brands on the market today.
Your quadcopter probably has a lot of great features and the flight controller handles them all. Some of the basic sensors in it include the gyroscopes and accelerometer that keeps your quadcopter level while flying and lets it speed up and slow down. You might have a quadcopter that also has barometric pressure sensors and a compass. Plus, the flight controller is what will also control any peripherals you may add to your copter, such as LED lights, sonar sensors and GPS.
Why you need a flight controller
Quadcopters, unlike fixed winged aircrafts, are typically harder to fly and are inherently unstable. They are unstable because they rely on the pilot to control it and keep it in the air flying level and straight based on the controls in your hand. Quadcopters do not have a fixed wing like airplanes.
The fixed wing on an airplane is what helps keep it level in the air. Your quadcopter could be stable in midair while hovering but as soon as you touch the controls and release it, the stability goes away. All it takes is one propeller to speed up or slow down for the quadcopter to title and crash unless you can bring it level quick enough. You do that by using a flight controller that can keep the propellers spinning at the same speed based on the directions you give it.
If you have ever flown a radio-controlled helicopter and then a quadcopter, you can see the difference in how they fly and why the quadcopter is more unstable. Quadcopters also waste more energy than a helicopter with the same payload because of it is using four smaller propellers to a helicopter's single large one. The quadcopter propellers are moving at a faster speed than a helicopter. The large propeller on a helicopter makes is more gyroscopically stable.
The flight controller is what keeps your quadcopter in the air. It is continuously reading sensor data and crunching numbers in order to make split second, minute adjustments to the motors of your quadcopter. They use gyroscopes for stability, accelerometers to measure and adjust the speed the quadcopter is moving, a magnetometer or compass to keep it moving in the right direction, a barometer to measure altitude and a GPS for the autonomous flying feature. All of these things work together to fly your quadcopter with just a simple push or pull of the controls.
Let’s talk firmware
Every flight controller runs using specialized firmware that works the quadcopter and all the built-in features. Most of the time, the firmware can be configured using your special software that runs on your computer, tablet or smartphone. Be aware of what the firmware runs on when you buy it as some firmware may not work with an iPhone or Mac while others may not work with an Android.
If you see the word “tuning” in conjunction with the firmware in your flight controller, it means you’re configuring your quadcopter. It’s sort of like turning your car. Every time you make changes to the PID, rates other settings, it changes how your quadcopter will respond and flies. Don’t expect to configure your quadcopter perfectly the first time you get a new flight controller. The GUI interface and parameters could be different from what you’re used to so there will be a bit of a learning curve.
So, you are familiar with the different firmware for your flight controller currently on the market, here is breakdown of the most popular applications:
Mini Quad and Racing Drones
- Betaflight - Betaflight is based off of Cleanflight and it is designed specifically to provide you with cutting-edge technology and performance, especially where acrobatic flying of your quadcopter is concerned
- Raceflight – another firmware based off of Cleanflight, Raceflight was manufactured for F4 boards and acrobatic flying
- KISS – this firmware is based on the open source Multiwii and was developed by Flyduino
GPS and Autopilot Systems
Firmware for GPS and Autopilot Systems usually control features such as way-point, loiter, return to home and more.
- iNav – this is based off of Cleanflight but focuses on GPS and Autopilot functions
Other Open Source Projects
- LibrePilot – this was previously known as OpenPilot
- Taulabs – this firmware is based off of OpenPilot
If you don’t want to fuss with firmware that you need to update and configure all the time, you can find flight controllers that don’t use it. Instead, the flight controller will have a built-in LCD screen that gives you the ability to change your settings on the go, if it lets you change the settings at all. You need to pay attention to this when you purchase the new controller in case you do want to be able to adjust how your quadcopter responds.
Additionally, some flight controllers can run multiple firmware. Just make sure that the controller you want works with the firmware that will make your quadcopter fly the way you desire.
Choosing the flight controller
So, what type of flying do you want to do with your quadcopter? There are really three categories quadcopter flying falls into: racing and freestyle flying; aerial photography and videography; and autonomous missions. One you are able to determine the type of flying you want to do most of the time, you can then research the firmware and the flight controller that is compatible with the firmware and purchase it.
Before you go as far as purchasing your new flight controller, there are a few other things you need to consider, namely the features that are available on your quadcopter and if the flight controller can handle them. Let’s run down them.
- Processor – Currently you can only choose from an F1, F3 and F4 processor. What does that mean? Basically, F3 processes faster than F1, and F4 processes faster than the others.
- Sensor: Gyro Model and Bus – You want to look into a Gyro BUS that is not vulnerable to electrical or mechanical noise, how well it samples and how fast your looptime can run. Basically, you want a Gyro BUS that is an SPI with an 8KHz+ refresh rate.
- Flash Memory for Blackbox – CleanFlight uses something called Blackbox to help configure your quadcopter. If you’re not using that firmware, then built-in data flash memory or an SD card will be enough for storing commands.
- Connector Types – This gets into the nitty gritty circuit board of your flight controller. Try to avoid plastic connectors as they are easy to disconnect and could melt if the board overhears. Same with solder pads. Try to find a board with through holes so you can use header pins or direct solder when you need to work on it.
- Integrated Voltage Regulator – This lets you power the board of the flight controller straight from the LiPo battery. Usually it will also measure your battery level for you and keep you informed of how much battery time is left.
- Integrated PDB – This lets you power the entire flight controller from the LiPo battery and eliminates wire harnesses and extra PDBs.
- Other extra features:
o Bootloader button
o Support for IR Transponder (for recording lap time in races)
o Integrated OSD
o Integrated VTX
o Baro/Mag (these are less important in racers)
Let’s get into the different flight controllers on the market now that you know what you want it to do.
KK2 CONTROLLER BOARD
If you are a beginner but ready to try your hand at building the board for your new flight controller, the KK2 controller board is a great place to start. It’s a popular board and it is inexpensive. It has an onboard display, which allows you to tune your quadcopter’s parameters without hooking it up to a computer. The menu makes it really easy to see what you are changing. While it doesn’t offer features like GPS, altitude hold, go home or autonomous waypoint navigation, it’s perfect for the beginner to learn on. It can also support a quadcopter with 4 to 8 rotors.
- No advanced features
- Self-leveling is slow and unimpressive
- The firmware usually needs updated as soon as you take it out of the box
TORNADO FC STM32F3
This flight controller has been specifically designed for anyone interested in FPV racing with their quadcopter. It is inexpensive but pretty powerful with an accelerometer that is able to keep up with your racing demands. It has 256K of flash memory as well as a math coprocessor that can handle the floating-point math required of a racing drone.
- Not what you want if you are interested in aerial photography
Crazepony Afro NAZE32
The Naze32 is a great flight controller for beginner and intermediate level pilots who are looking for a very well designed and built product. It’s a 32-bit controller that comes in two versions. The Acro Naze32 is designed for users who are looking at racing and other types of sports flying.
The Full Naze32 is straightforward flight controller that has all the standard features plus a compass and barometer sensor. Its claim to fame is the stability control it gives your quadcopter and it has performed better than some of its competitors. It’s also been praised for its fast control response. Small and lightweight, the Naze32 really is ideal for sport quads.
- Unreliable GPS
- No onboard display requiring a computer for tuning
- Cannot handle advanced features like waypoint navigation and autonomous flying
Photographers and videographers will appreciate this flight controller as it is designed just for them with every feature they want to take stunning videos and photos. DJI is known for their user-friendly products and their flight controller is no exception.
It is stable, offers the pilot Go Home and hold altitude, and can fly autonomously. It’s all plug and play, providing accurate and reliable use. You don’t have to do a lot of fine tuning with this flight controller. It’s really minimal input from you to get smooth, high quality video and crystal clear photos.
- This flight controller will run you about $150 on Amazon.com when they have it in stock
Check out the best DJI Phantom Alternatives on the market
Fans of autonomous flying who will use a lot of telemetry will really like this flight controller. It is feature rich and has an excellent onboard GPS. This is the same controller board that you find in a wide array of popular radio-controlled airplanes and cars. It’s very to tune with its 3-axis gyroscope, 5Hz GPS, 3-axis accelerometer, barometer and magnetometer. It’s a great board for videography and telemetry with extremely accurate sensors throughout.
- Expensive for what you get
- Considered outdated by many in the quadcopter industry
BUMBLEBEE FLIGHT CONTROLLER
The Bumblebee is very similar in its features to the DJI Naza except it only works with quadcopters. If you need it for some other type of radio controlled flying vehicle, you need to look elsewhere. It’s relatively easy to set up and tune.
- Works with only a select few ESCs
- Hard to find on websites such as Amazon
The CC3D is a 32-bit flight controllers and considered one of the first on the market. While you might think that the technology is old, believe it or not it still works really well. It supports LibrePilot and CleanFlight/BetaFlight without an issue thanks to an SPI Gyro Bus and the processor is only an F1.
- Has problems sinking the flight controller to the computer and to the quadcopter
- F1 processor is too slow for some of the functions
Multiwii is an open source project that actually got its start as the firmware inside the Nintendo Wii Nun chuck. It controlled the gyro and accelerometer sensor and that’s how this flight controller got its name.
Quadcopters got their start about the same time and since the open code worked so well – and Multiwii was one of the few at the time – it was easy to port the code into other applications and develop the firmware for other platforms and projects.
While there are many version available of the Multiwii board, the MultiWii Pro is one of the most popular. It is based on the Arduino and has the ATmega2560 processor inside. This flight controller features a gyro, accelerometer, barometer and magnetometer. This particular controller also can support such functions as GPS and sonar sensor. It can work a quadcopter as easily as it can control a radio-controlled plane. Plus, the price is right for one of these flight boards.
- Software interface is not as cosmetically good looking as other flight controllers
This flight controller is a high-quality PDB that consists of a 6-layer PCB, which helps keep electrical interference from the gyro. All of the power rail traces and other components are run separately from the sensor circuits. It is a really sweet flight controller and when put together right, you can avoid a lot of interference from things like video. High-quality PDBs like this one don’t require filtering thanks to the mini power board and a built in current sensor.
Earlier versions of this flight controller only supports dRonin software but later editions supports both dRonin and Betaflight. It’s very easy to setup thanks to setup wizards that walk you through the whole process and gets you flying in no time.
- Older versions only support the dRonin software
- Terminology and features are different than most other flight controllers
- dRonin’s Autotune does not work with every quadcopter
Developed by FuriousFPV, the Radiance flight controller is one of the new stand-alone flight controllers on the market. FuriousFPV is well known for their innovative products and how fast they turn them out.
The Radiance flight controller is similar to the company’s Kombini FC without a PDB. It’s great for pilots who want to get a stand along flight controller for a reasonable price and the ability to run the PDB separate. Since the flight controller came out in October 2016, you’d think there would be more information on it, but there is still very little out there. We expect there to be changes when the final version is released.
What we do know about it is this. It has an F3 processor and MPU6000 ACC/Gyro Sensor that connects with a SPI. It has a LiPo battery input, an onboard 5V (2A)/12V voltage regulator with LC filter, 6 ESC output that supports hexacopters and ILAP transponder. You’re able to power the flight controller straight from the battery without worrying about additional cables you need to clean up. We think it’s going to use the same firmware as the Kombini.
- There is still very little information available on this flight controller
KOMBINI FLIGHT CONTROLLER
Like the Radiance, the Kombini flight controller is manufactured by Furious FPV and is considered a step-up from the Piko flight controller, its sister product. The Kombini is an F3, PDB integrated flight controller that allows a higher current than the Piko. It supports up to a 5S LiPo battery with a built in 5V 2A BEC.
It supports a transponder, SBus, SumH, SumD, Spektrum 1024/2048, XBus, and PPM with a built in Spektrum satellite port. It has a built-in LC filter and push button for bootloader. The layout of the flight controller is very similar to the Piko BLX, so if you are already familiar with the Piko, you’ll have no problems getting the Kombini up and running.
- Prototype board has problems with the 5V failing when it tries to power up with the LiPo battery and the USB is unplugged
SERIOUSLY PRO RACING F3
This flight controller was designed by the same people that developed the Cleanflight firmware. If you are familiar with the Sparky v1 (STM32F3), then you’ll know the F3 processor that powers this flight controller. Many in the industry consider this board the successor to the NAZE32 full board. It is a 32-bit flight controller.
- There is very little information available about this flight controller
- Firmware needs to be updates as soon as you take it out of the box
This controller offers you an inexpensive alternative to many of the other flight controllers on the market. It has the newest 32-bit chip technology integrated into the sensor technology. This solves problems with having an 8-bit CPU and the CPU occupancy being too high. It has an external LED, high-performance processor and can operate the NuttX RTOX real time operating system.
With an integrated back up power, you get redundant input and failover on the power supply. It comes with an automatic and manual mode and has a multi sound buzzer interface. It comes with a Micro SD card to record the data when you have your quadcopter in the air.
- Wire connection is not good and causes the flight controller to short out during use
KISS flight controller
Designed by Flyduino for mini quadcopters, the KISS flight controller has an F3 processor and uses a firmware that has been written from scratch. The PID controller is a completely float point based. To configure the flight controller, you use an app in Chrome on your computer. Currently there are only two tabs in the app – configuration and data output – and no CLI commands. Additionally, the GUI has a filter on it to help keep your quadcopter from shaking so badly and reducing the noise.
- Choosing air frame in the GUI when tuning may not be useful based on your quadcopter
- Custom firmware may not work with all quadcopters
- No support for the OSD menu
- Board layout is not convenient
- Solder pads are used instead of header pin holes
- USB port heats up and causes connectors to pop off
- Manual could be improved
Any time you purchase hardware – whether it’s from an electronic store or from Amazon.com – you need to be prepared for it to not work properly or not work at all. There is no piece of hardware on this planet that is built or designed perfectly. A flight controller board is a piece of computer hardware and it is prone to faults, just like anything else.
When you first sync the controller to your quadcopter, make sure you are in an environment where you can test it out safely. The quadcopter could easily lose control if there is something wrong with the flight controller or one of the circuits on the board. Anything could go wrong, from your quad crashing to the flight controller catching on fire if the wires aren’t connected properly.
You don’t want any malfunctions to harm other people or damage property. Always follow the directions that come with your flight controller to make sure you set it up properly and read any release notes that might be available on line prior to the first flight.
Read up on the quadcopter you are interested in buying before committing to it and a flight controller for it. Learn everything you can about it so that you know what additional equipment you may need, if you need to purchase a camera for your quad and what type of batteries it takes.
Also, be aware of what type of setup your drone may require. Not all of them are ready to use as soon as you open the box. There may be some setup required especially if you are syncing a new flight controller to your quad. Make sure the firmware is also compatible so your flight controller can handle all of the things you want your quadcopter to do.
Always be aware of the area you are flying your quadcopter in and any FAA regulations in the area. Invest in FAA flight zone information so you can keep it out of any no-fly zones. Many quads are required to be registered with the FAA. Make sure you check in your area to see if you need to register it prior to use. Use your quadcopter responsibly and always ask before videoing any type of event where others are involved.
If you like this article, check out our article on drone racing