This project is a RC quadrotor helicopter (quadrocopter, quadcopter, quadricopter, etc). It's a RC helicopter that uses 4 rotors.
Watch it in 720p
You need some pre-requisite skills:
When one rotor spins faster than the rotor on the opposing side, the faster side will have more lift, and thus the helicopter will tilt. When the helicopter is tilted, the air is being blown slightly sideways instead of directly down, and the helicopter will move.
The propellers also need to be in counter-rotating pairs, two spin clockwise and two spin counter-clockwise. This way, the helicopter does not spin on the vertical axis since the rotational enertia is cancelled out. But when the pair that's spinning in one direction is faster than the other pair, the helicopter will spin on the vertical axis. This is how the helicopter controls its direction.
We will be building a flight controller circuit that contains an accelerometer and gyroscope sensor so that a microcontroller can detect undesired changes in the helicopter's angle, and adjust each rotor's speed accordingly to counter the variation. This microcontroller will do this hundreds of times per second, keeping the helicopter stable in the air.
The flight controller is a completely open source circuit. The circuit schematic and PCB files are provided. The flight controller is completely Arduino compatible. The source code is a modified version of AeroQuad (open source Arduino based quadrocopter control code). The flight characteristics can be adjusted using AeroQuad's configurator utility.
Attached is a diagram that shows you the direction of spin for each motor, remember this diagram! You won't be able to fly if your setup does not follow this diagram.
This microcontroller will also take input from a RC radio receiver, so you can control the helicopter from the ground using a RC radio transmitter.
This helicopter will use four brushless motors. Each motor will be controlled by an ESC (Electronic Speed Controller). The ESCs will be controlled by the microcontroller.
A lithium polymer battery will power the entire contraption.
Summary of Downloads:
Watch it in 720p
You need some pre-requisite skills:
- How to use Arduino, enough to get started
- Soldering, wiring, basic electronic skills
- Basic hand tool operation
When one rotor spins faster than the rotor on the opposing side, the faster side will have more lift, and thus the helicopter will tilt. When the helicopter is tilted, the air is being blown slightly sideways instead of directly down, and the helicopter will move.
The propellers also need to be in counter-rotating pairs, two spin clockwise and two spin counter-clockwise. This way, the helicopter does not spin on the vertical axis since the rotational enertia is cancelled out. But when the pair that's spinning in one direction is faster than the other pair, the helicopter will spin on the vertical axis. This is how the helicopter controls its direction.
We will be building a flight controller circuit that contains an accelerometer and gyroscope sensor so that a microcontroller can detect undesired changes in the helicopter's angle, and adjust each rotor's speed accordingly to counter the variation. This microcontroller will do this hundreds of times per second, keeping the helicopter stable in the air.
The flight controller is a completely open source circuit. The circuit schematic and PCB files are provided. The flight controller is completely Arduino compatible. The source code is a modified version of AeroQuad (open source Arduino based quadrocopter control code). The flight characteristics can be adjusted using AeroQuad's configurator utility.
Attached is a diagram that shows you the direction of spin for each motor, remember this diagram! You won't be able to fly if your setup does not follow this diagram.
This microcontroller will also take input from a RC radio receiver, so you can control the helicopter from the ground using a RC radio transmitter.
This helicopter will use four brushless motors. Each motor will be controlled by an ESC (Electronic Speed Controller). The ESCs will be controlled by the microcontroller.
A lithium polymer battery will power the entire contraption.
Summary of Downloads:
- Over 100 pictures in all the steps
- Step 9 contains flight controller circuit and PCB files
- Step 10 contains bootloader and core for microcontroller
- Step 12, 13, 14 contains demo Arduino sketches
- Step 26 contains the flight control software
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Signing UpStep 1: Parts
RC radio transmitter and receiver
You need 4 channels minimum but I am begging you to get one with 6 channels. Also get one that uses 2.4 GHz technology if you can. Turnigy has a 9 channel model that is actually very inexpensive, and it runs on an AVR microcontroller that you can put custom firmware on. Personally, I have a old $25 radio that uses 75 MHz FM but I've converted it into a 2.4 GHz radio using a conversion kit.
Four brushless outrunner motors are needed. I used hexTronics 20-22L (this number represents the diameter and coil winding configuration of the motor, there's also a kv value that relates speed and power, higher kv = morepowerful faster motor (thanks to the correction from slick8086, I was incorrect to relate power to Kv, it's the RPM that's faster if Kv is higher), 800 to 1200 is acceptable motors. They come with a ton of parts (the bullet connectors, heatshrink, propeller adapter, the screws you need, mounting plate, spare shaft and spare C-clip, all included). Get extras just in case one gets damaged in a crash.
Four brushless motor electronic speed controllers (ESC) are needed. One that is rated for 18 amps is enough. I have heard good things about the Turnigy Plush ESCs because they support high update frequencies (more frequent adjustments means more stable flight). I got the HobbyKing brand clones of the Turnigy Plush ESCs because they are cheaper.
Some ESCs are "card programmable", meaning you can change their configuration using a cheap ($6) programming card, which is really convenient. Buy the programming card that is compatible with the ESCs you've chosen. I got the Turnigy ESC programming card because they are compatible with my ESCs.
You'll obviously need a battery. You will use a 3S1P lithium polymer battery that is rated at least 20C (this is the discharge rating). 3S means 3 cells in series, 1P means one set in parallel. This will give you a combined 11.1 volts. I suggest a 2500 mAH capacity battery (or more). A general rule of thumb is doubling the capacity of the battery means 50% increase in flight time (due to the extra weight).
More info on batteries here: http://www.rcgroups.com/forums/showpost.php?p=1315199&postcount=1
Make sure you pay attention to the type of connector that comes attached to your battery. You're going to need to get the matching connector. I've personally built my entire helicopter using bullet connectors. 4.0mm bullet connectors for the battery and 3.5mm bullet connectors for everything else (the motors come with 3.5mm bullet connectors). (You can get other connectors such as XT-60 connectors, just watch your polarities, also note that all my pictures show bullet connectors)
You need a lot of heat-shrink tubing to act as insulation when using the 3.5mm bullet connectors. Get different colours so you can tell which wire is which.
You need 12 gauge stranded core wire. It must be 12 gauge or thicker to handle the current. It must be stranded core so that it is flexible. Get different colours so you know which wire is which polarity. The best wire is fine stranded copper wire with silicon insulation, but this is expensive.
Get a good battery charger, it must be able to balance and charge multi-cell lithium polymer batteries. I have one of these Turnigy chargers that have many settings, a LCD, and cooling fan, very nice. I also use a laptop power brick to power the charger since an ordinary wall adapter won't be able to handle the current required.
Get a battery monitor so you know when your battery is low. A lithium battery will become permanently damaged if you drain it below a certain threshold. Having a monitor will prevent you from damaging your battery. I have one of these that reports the status of each cell.
The quadcopter's frame I use is this one from HobbyKing. For $15, you get every part you need, plus every screw and nut you need. In comparison, a stick of aluminum would cost me $10 from Home Depot, which is not economical in comparison. I suggest you buy several frames so you have plenty of spare "arms" if you crash (plus plenty of spare screws and nuts).
The propellers must be in counter-rotating pairs (a "pusher" and a "puller"). I use 10x4.7 APC slow-fly propellers. 10 indicates diameter in inches and 4.7 indicates pitch. Larger diameter means more lift but requires more powerful motors. 10 inches is about right for the frame size I am using.
You'll need a entire flight controller circuit (meaning another entire bill of material), I will talk about this in detail later. Meanwhile, you'll need a USB-to-serial cable (FTDI cable) and an AVR programmer.
Plenty of servo cables are required to connect stuff. A minimum of 6 female-to-female cables is required for the 6 channels from the RC radio receiver to the flight controller.
Velcro tape and double sided velcro strapping will be useful as a lightweight way of mounting things and strapping in the battery.
Get a bubble/spirite level (like this one) to help with sensor calibration.
Make sure you get plenty of extras, stock pile on wire, cables, connectors, heat-shrink tubing, electrical tape, glue, screws, etc.
You need 4 channels minimum but I am begging you to get one with 6 channels. Also get one that uses 2.4 GHz technology if you can. Turnigy has a 9 channel model that is actually very inexpensive, and it runs on an AVR microcontroller that you can put custom firmware on. Personally, I have a old $25 radio that uses 75 MHz FM but I've converted it into a 2.4 GHz radio using a conversion kit.
Four brushless outrunner motors are needed. I used hexTronics 20-22L (this number represents the diameter and coil winding configuration of the motor, there's also a kv value that relates speed and power, higher kv = more
Four brushless motor electronic speed controllers (ESC) are needed. One that is rated for 18 amps is enough. I have heard good things about the Turnigy Plush ESCs because they support high update frequencies (more frequent adjustments means more stable flight). I got the HobbyKing brand clones of the Turnigy Plush ESCs because they are cheaper.
Some ESCs are "card programmable", meaning you can change their configuration using a cheap ($6) programming card, which is really convenient. Buy the programming card that is compatible with the ESCs you've chosen. I got the Turnigy ESC programming card because they are compatible with my ESCs.
You'll obviously need a battery. You will use a 3S1P lithium polymer battery that is rated at least 20C (this is the discharge rating). 3S means 3 cells in series, 1P means one set in parallel. This will give you a combined 11.1 volts. I suggest a 2500 mAH capacity battery (or more). A general rule of thumb is doubling the capacity of the battery means 50% increase in flight time (due to the extra weight).
More info on batteries here: http://www.rcgroups.com/forums/showpost.php?p=1315199&postcount=1
Make sure you pay attention to the type of connector that comes attached to your battery. You're going to need to get the matching connector. I've personally built my entire helicopter using bullet connectors. 4.0mm bullet connectors for the battery and 3.5mm bullet connectors for everything else (the motors come with 3.5mm bullet connectors). (You can get other connectors such as XT-60 connectors, just watch your polarities, also note that all my pictures show bullet connectors)
You need a lot of heat-shrink tubing to act as insulation when using the 3.5mm bullet connectors. Get different colours so you can tell which wire is which.
You need 12 gauge stranded core wire. It must be 12 gauge or thicker to handle the current. It must be stranded core so that it is flexible. Get different colours so you know which wire is which polarity. The best wire is fine stranded copper wire with silicon insulation, but this is expensive.
Get a good battery charger, it must be able to balance and charge multi-cell lithium polymer batteries. I have one of these Turnigy chargers that have many settings, a LCD, and cooling fan, very nice. I also use a laptop power brick to power the charger since an ordinary wall adapter won't be able to handle the current required.
Get a battery monitor so you know when your battery is low. A lithium battery will become permanently damaged if you drain it below a certain threshold. Having a monitor will prevent you from damaging your battery. I have one of these that reports the status of each cell.
The quadcopter's frame I use is this one from HobbyKing. For $15, you get every part you need, plus every screw and nut you need. In comparison, a stick of aluminum would cost me $10 from Home Depot, which is not economical in comparison. I suggest you buy several frames so you have plenty of spare "arms" if you crash (plus plenty of spare screws and nuts).
The propellers must be in counter-rotating pairs (a "pusher" and a "puller"). I use 10x4.7 APC slow-fly propellers. 10 indicates diameter in inches and 4.7 indicates pitch. Larger diameter means more lift but requires more powerful motors. 10 inches is about right for the frame size I am using.
You'll need a entire flight controller circuit (meaning another entire bill of material), I will talk about this in detail later. Meanwhile, you'll need a USB-to-serial cable (FTDI cable) and an AVR programmer.
Plenty of servo cables are required to connect stuff. A minimum of 6 female-to-female cables is required for the 6 channels from the RC radio receiver to the flight controller.
Velcro tape and double sided velcro strapping will be useful as a lightweight way of mounting things and strapping in the battery.
Get a bubble/spirite level (like this one) to help with sensor calibration.
Make sure you get plenty of extras, stock pile on wire, cables, connectors, heat-shrink tubing, electrical tape, glue, screws, etc.
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Thanks for the quick response,
Nikhil
I finally finished making the quadrotor but I was wondering how to turn it off.
It's kind of a stupid question but are you just supposed to unplug the battery or is it necessary to install a switch
A true kill switch that can handle that much current is not feasible
i cant use avrdude is there any other program to use the bootloader and please if you can explain how to use avrdude and plz plz upload the docs in any site other than google code because i cant use google code if you can please email it to me
could i use Arduino mini for my flight controller instead of designing my own cause I dont understand how to design it at all
Thank you
Please Reply
Oh and can you give a link of the Arduino mini to buy because I'm really confused
Thank you
My previous comment has been there for a long time and you still havent responded
Please reply
Aug 3, 2012. 10:22 PM
Yea, just look at AeroQuad Mini, or MultiWiiCopter, both of them actually use the Arduino Mini
Your Quadcopter is an excellent one. I was just wishing that if you would kindly tell me , from where did you order the frame kit, fans and the motors.
If you would be kind, can i have your email address.
Thanks.
My email is on my website, in the title as an image so spam bots can't detect it.
Amazing instructable you've created! I'm currently nearing the final stages and am about to program but was just wondering about a couple of things as I'm new to all this and completing this for a school project.
Just wondering with the solder jumpers, if the solder jumps across the whole thing (3v3 and 5v as well as ser0 and ser1) or if you choose which to use, and whether all 4 LED's should be lit when it is plugged in for programming, as currently only LED-PWR and LED1 are lit
Thanks!
I plan to start building this in my schoolâs manufacturing shop so I would like to get my hands on a PCB sooner than later. I would earnestly appreciate a quick reply.
Sincerely, Alexander
what would happen if you have all of the props spinning in the same direction??
I am currently making a quadrotor and i am waiting for the rc parts(including the props!!!!) the props i am getting is fine for my motor, but they are 4 of the same!!!!! the shipping costs a lot and i don't really want to spend 8 quid for something that costs only 2 quid!!!! is there any way to salvage this??
thanks
lil tinkerer ;)
Or could I mount 2 of them on the underside of the quadrotor so that they will be opposite to the other 2 so it won't spin on its yaw axis??
can u plz tell me that which 1 is the best brushless dc motor for this project wih low cost also.......
and what is the cost of 1 dc motor???
thanks for posting your designs.
I've started building my own quadrocopter following your instructable.
I'm currently building the microcontroller and i was wondering if the SJ1-18 were switches? I am assuming they are but just wanted to get some more info about that from you. Also there were no surface mount switches included in your BOM.
Maybe you were intending readers to just solder a piece of striped wire? that would be more permanent but it would also eliminate the danger or switching between 3.3v and 5v accidentally. Thanks for you help
A piece of wire would also work, or 0-ohm resistors, but the cheapest way is to just use a lot of solder.
So I got my micro controller ready go but I am not too familiar with flashing the boodloader. I also do not have an AVR programmer, do I even need one?
If you could give me some more info about this step or direct me to somewhere where i can get the info i would be grateful
all you do is hook up the programmer to the ISP header, and run the AVRDUDE command to burn the bootloader .hex file, look up how to use AVRDUDE to learn more