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Step 12: Connect Radio Receiver to Flight Controller

With both the flight controller and the radio receiver mounted on the quadcopter body, in this step we will electrically connect the flight controller and radio receiver using three-wire servo connectors.

With the flight controller and radio receiver both attached to the quadcopter, we can now connect them together electrically.

Now, I am going to take a moment to explain the connections on the radio receiver, then, in the next section, I will explain the connections on the KK2.1, and finally I will explain how to attach the two.

About the Radio Receiver Connections

So, if you take a look at the radio receiver, you will notice that the connections come in sets of three pins. The label on the top of the receiver shows which rows belong to which channel. Each channel corresponds to a different action on the radio transmitter. For example, channel one receives commands when you move the right stick left and right, channel two receives commands when you move the right stick up and down, et cetera

Each of the three pins for each channel carries a different electrical connection. There is a tiny little legend underneath the label for channel one that shows which pin carries which signal, but this legend is difficult to see, so let me put it in words:  the outside row of pins is ground, the middle row of pins is power, and the inner row of pins is signal.

About the KK2.1 Connections

Now that you understand the connections on the radio receiver, direct your attention to the flight control board. Looking at the board from the bottom (button side) you will find the connections for the radio receiver to the left of the screen. There are five rows of three pins. Just like on the radio receiver, each row of three pins corresponds to a different radio transmitter channel.

The channels on the KK2.1 board are a bit more difficult to understand than the ones on the radio receiver though because, if you take a look at the bottom of the board (you might need to peek through a slot in the mounting plate), you will notice that the rows are labeled for airplanes, not for quadcopters. Starting with the top row of pins, the order goes aileron, elevator, throttle, rudder, auxiliary. These labels correspond to the various control surfaces (flaps) used to control airplanes in flight. So we will need to form a mental map of the way these airplane controls correspond to quadcopter controls.

Just like airplanes have four control channels, so too do quadcopters, but the terminology used for quadcopter control is a bit different. The four control channels are roll, pitch, yaw, and throttle. To translate the KK2.1 receiver connections from airplane terminology to quadcopter terminology, we just need to substitute the airplane-related words for quadcopter-related words:
 

aileron → roll
elevator → pitch
rudder → yaw
throttle → throttle (which means altitude for quadcopters)

This terminology is actually really important. You should make sure to memorize the relationship between airplane controls and quadcopter controls because throughout the rest of this tutorial I will often be using these terms interchangeably; and this is the same for many other sites. It will make your life much easier if you do not have to come back here to look at the above chart every time you encounter one of these words.

The auxiliary connection is the same for airplanes and quadcopters since it is just used to control other accessories like lights or the auto-leveling feature.

Connecting the Radio Receiver to the Flight Controller

Armed with your new knowledge of the radio receiver and flight controller pin layouts, we can now connect the two parts  together. Before we begin, there is just one more piece of information to consider:  on the radio receiver, all of the ground and power pins (the outside and middle pins) are connected together. Therefore, we only need to connect one ground pin and one power pin to the KK2.1 flight control board. The practical upshot of this is that we will only need three servo leads to complete all the electrical connections.

First, plug one of the servo leads across the three pins on the radio receiver that correspond to channel one. Orient the plug so that the brown wire is on the outside. Then, plug the other end of the servo lead into the aileron plug on the KK2.1 board, which is the top one. This plug should be oriented with the brown wire on the outside pin. On my quadcopter, I stuck the wire underneath the flight control board just to prevent the wire from hanging out in open air.

Now for the next wire. Since we’ve already connected a ground and power wire from the KK2.1 board to the radio receiver, we will only need a signal connection for the remaining three signals. Conveniently, the servo leads happen to have three wires. So, connect the second servo lead going down the row of inside pins (signal pins) with the yellow wire plugged into channel two, the red wire plugged into channel three, and the brown wire plugged into channel four. Then, plug the other end of the wire into the pins closest to the screen on the KK2.1. The yellow wire should be closest to the aileron plug.

There is one last connection to make, the connection for the auxiliary channel, which we will use to turn on and off the self-leveling feature of the KK2.1 via the left switch on the radio transmitter. More on that later, for now connect another servo wire, this time across the entire fifth row of columns on the radio receiver. Connect the other end across the fifth row of pins on the KK2.1.

can i use 5000mah 2s turnigy battery
<p>Do you have to revert the 3 pin connections for the q brain back to how they were in order to use the BESC programming card? I don't want to do this each time because I want to change the song selection for the q brain. Any easier way to do this?</p>
Here is the connectionHereh
Here is the connectionHereh
Pls I am using a flight board KK2.1 and. Hk 16A V2 6 channels receiver. I used 2 servo cables to link them, (which am not sure is correct), but when I try to arm my motors, I get a set of steady beeps. What could be the reason for that?
<p>Great instructable. Followed a lot of this when I made my Dead Cat Defibrillator. Only thing that doesn't seem to be right are the mixer settings. For motor 3 (right rear) and 4 (left rear) they seem to be the wrong way round. I based mine on the YouTube video from HobbyKing which has 3 as 100, 71, -71, 100 and 4 as 100, -71, -71, -100. Hope this helps anyone else that get some strange flight characteristics with the settings given here.</p>
<p>Thanks for the recipe, flies really well now. But there are multiple errors in the mixer editor settings you have listed.</p><p>Importantly, the signs for the rudder numbers for motor 3 and 4 are mixed up! Motor 1 and 3 should have positive numbers for rudder, motor 2 and 4 should have negative numbers. Same applies for aileron.</p><p>I have marked in <strong>Bold </strong>the places when my number have the <u>opposite sign</u> of your numbers. My numbers are also slightly different just because i measured the angles differently from my kk unit. <br>39 comes from being sin(23 degrees) which is the angle i measured to the front arms (see picture).<br>92 = sin(90-39) =&gt; 0.92 =&gt; 92<br>73 = sin(47)<br>68 = sin(90-47)</p><p>Motor 1:<br>Throttle: 100<br>Aileron: -39 <br>Elevator: 92<br>Rudder: 70</p><p>Motor 2:<br>Throttle: 100<br>Aileron: 39 <br>Elevator: 92<br>Rudder: -70</p><p>Motor 3:<br>Throttle: 81<br><strong>Aileron: 73</strong><br>Elevator: -68<br><strong>Rudder: 100</strong></p><p>Motor 4:<br>Throttle: 81<br><strong>Aileron: -73</strong><br>Elevator: -68<br><strong>Rudder: -100</strong></p>
<p>What is the length of your flight???</p>
How durable is this model compared to other copters? Do you recommend flying this if it's my first copter, or would you suggest a more crash friendly one?
<p>Ok, I'm a little confused. Your pic of the tape on the controler is clearly mode 1 but your link to the tx/rx combo is mode 2. Which one are you running?</p>
<p>This is the very best build report I have read! </p>
<p>Thanks for taking time to put together such a comprehensive build guide. Much appreciated.</p><p>I can buy all these parts in the UK. But, I have a DX6 AR7000 and an AR6000. Will these work OK with the setup given?</p>
<p>I want to build this but I just can't find a vendor who ships those parts to Germany. Can anybody help me?</p>
<p>i found when i inputed these settings my motor 1 and 2 went much <br>more forward than sideways, i found the Aileron and Elevator settings <br>for motors 1 and 2 were slightly switched around (could be a new version <br> of the software or maybe just an oversight when typing up this amazing <br>build? lol)<br><br>I found these work best for motors 1 and 2 on my KK2.1 <br></p><p><strong>Motor 1 Mixer Editor Settings</strong> </p><ul><li> Throttle: 95 <li> Aileron: -94 <li> Elevator: 34 <li> Rudder: 78 <li> Offset: 0 <li> Type: ESC <li> Rate: High</ul><p><strong>Motor 2 Mixer Editor Settings</strong> </p><blockquote> <br> <br><ul><li> Throttle: 95 <br><li> Aileron: 94 <li> Elevator: 34 <li> Rudder: -78 <li> Offset: 0 <li> Type: ESC <li> Rate: High</ul></blockquote><p>Correct me if im wrong but that gave me the correct orientation of the motors</p>
<p>i found this section to be a bit confusing at first until i relized i didnt have enough 3pin connectors...in the parts list it only says 1 CM male to male connector so thats what i bought...maybe should be revised to say 3 or 4 lol</p>
<p>1-10CM male to male**</p>
<p>I am currently in the middle of this build. But it seems my controls are all backwards. For example left is right and throttle up is throttle down ect. Anybody else having this problem??</p>
<p>Just reverse the affected channels on your transmitter</p>
<p>Very nice! I was looking for something like his. A question: Is there place to install a gimbal underneath?</p><p>Thanks</p>
Great instructable! Thank you so much, I followed all your instructions and my dead cat flew first time perfect!!! Cheers.
<p>Sounds dumb but i can't get it right!<br>I Have a Graupner MX-12, with the throttle on the right side.</p><p>In Your Instructable, it's on the left side, so how do I have to swap the connectors, so the KK Board also recognizes the right stick as a throttle?</p>
<p>Why is finding downloads for the latest KK2.1 board firmware such an elusive thing? Google always takes me to that gigantic thread on RC Groups where finding any links is like finding a needle in a haystack. Where the heck does one find KK2.1 firmware updates?</p>
very hard
<p>Hi, useful article but have one comment regarding prop balancing - don't you have the prop balancer assembled wrong? The conical elements should normally have the tips of the cones facing each other, they are designed so that they self centre on the hole in the propeller. Also there is a second step to balancing which you haven't mentioned here - to balance the hub (often referred to as vertical balancing). Doesn't make as much different as the horizontal balance but worth doing. Enjoy your flying, R</p>
<p>Hi,</p><p>Congratulations for this great Instructable. It was very useful and complete. I built my Dead Cat last week.</p><p>I was able to buy all parts from HobbyKing (USA and Europe Warehouse). I bound it to my Spektrum DX6i with a Spektrum AR610 receiver.</p><p>I found two missing things when building it:</p><p>- in step 6, &quot;Mount motors&quot;, I did not get the needed screws because they do not come with the motors. I had to look for suitable screw all over my house (and I finally used some screws from a PC). For the record, motor's package says &quot;Bolt thread: M3*4mm&quot;</p><p>- in step 9, &quot;Mount Flight Controller&quot;, I did no get the white plastic parts you are using to mount the KK board. But I bought a KK 2.1.5 since the KK 2.0 is not sold anymore. I had to used some nuts instead (3 nuts for each foot).</p><p>When I tried to fly it for the first time it completely flipped over (from right to left). I broke a prop :( I finally discovered that I had to first load a motor layout in the KK 2.1.5 menu. I chose &quot;X Quadcopter&quot; and then applied settings for the motors (step 18, mixer editors) (I used slightly different settings I found in a Youtube video).</p><p>I also add some LEDs to it, and some FPV gear, but I did not yet tried to fly it in FPV only.</p><p>FPV parts are:</p><p>- Camera: <a href="http://www.securitycamera2000.com/products/-RunCam-600TVL-Plastic-Housing-FPV-Camera-%252d-DE.html" rel="nofollow">http://www.securitycamera2000.com/products/-RunCam...</a></p><p>- Video Tx/Rx: <a href="http://www.securitycamera2000.com/products/BOSCAM-Mini-8CH-5.8G-400mW-Wireless-FPV-Transmitter-Receiver-Kit-%252d-DE.html" rel="nofollow">http://www.securitycamera2000.com/products/BOSCAM-...</a></p><p>- Goggle: <a href="http://hobbyking.com/hobbyking/store/__53706__Quanum_DIY_%3Cspan%20style=" rel="nofollow">http://hobbyking.com/hobbyking/store/__53706__Quan...</a></p><p>- Antennas: <a href="http://www.hobbyking.com/hobbyking/store/__49827__ImmersionRC_5_8GHz_Circular_Polarized_SpiroNet_Antenna_V2_RP_SMA_.html" rel="nofollow">http://www.hobbyking.com/hobbyking/store/__49827__...</a></p><p>My Quadcopter now flies quite well! I'm looking forward to fly it more but it's kind of freezing for the moment... :)</p><p>I attached a picture of it.</p><p>Thank you,</p><p>Alex</p>
<p>Hi there, I have a deadcat 450, I also just bought a Qbrain but cannot seem to get this darn thing working, please could you be more specific about the Cabling!</p>
Hi. What settings do you have in your radiocontroler??
<p>I's using an OrangeRx DSM2 reciever without numbers. How would I wire it correctly?</p>
<p>Hello I bought Qbrain and Naza.</p><p>can you post a picture to see x </p><p>how did the connection between fate and Qbrai 4x25A naza m-lite? , Thank you</p>
<p>My motors did not come with the motor mounting screws as depicted in this picture. I purchased the &quot;Turnigy Multistar 2213-980Kv 14Pole Multi-Rotor Outrunner&quot; as listed in the parts list but there are no phillips screws with them. The motors on hobby king also dont show these screws. looking at the local hobby stores and hardware stores trying to find some that will wrk but I have not had any luck.</p>
<p>Realy great instructable, but I think that yu need to charge battery at LiPo balance mode, and not at normal charge mode. In LiPo balance mode, charger will balance each of the cell separately, so is more safe, and better for battery</p><p>:)</p>
<p>Hi great instructable, how can I connect the Q-brain to the KK2.1 voltage sensor to make use of the low voltage alarm? I cant seem to figure that out. Any help is appriciated. </p>
<p>So I am in the process of scratch-building my first quadcopter, and I am trying to use a Turnigy programming card to program my Q-Brain 4-in-1 ESC. I plug the Q-Brain in to the programming hub, and that into the programming card, and then plug in the battery to an XT60 connector I soldered onto the ESC, but the programming card doesn't light up or respond. What am I doing wrong, and what could a possible solution be?</p>
<p>Never mind, I finished the build completely! Great instructable, although I noticed that some of the mixer settings were flipped, possibly because of the recent firmware update.</p>
<p>Great instructable and now I definitely want a quadcopter for my own! One question, instead of buying a SK450 Dead Cat frame for the quadcopter could I lasercut my own such as this: (http://www.thingiverse.com/thing:113497/#files)? My idea was that it would be easier to repair broken arms and what not if I could create my own frame. I plan on using the exact same parts as the list provided but change the frame. Would this theoretically work?</p>
<p>Thank you for this great instructable ! Ordered all the parts from HK ! Looking forward for the delivery ! </p>
I voted. :)
I made my first flights and crashes today (I never flew before). Yes, I swapped motors 3 &amp; 4. I need to recalibrate the motors again; since the do not start at the same time. Thanks for the instructions.
<p>Nice Work DUDE... Voted </p>
<p>A stunning instructable! Very well presented in depth. Thanks for sharing!</p>
<p>Assuming they are compatible; can anyone tell me how to connect the Q-Brain to a DJI Naza Lite (http://www.dji.com/product/naza-m-lite). Thanks!</p>
<p>Nice work! I just finish my deadcat last week;) Just a question, are you sure that the mixer editor settings are correct? I think that you switch the third and fourth motors! Let me know!</p>
<p>please please upload video step by step please :( . so that it is more easy to understand and fix it </p>
<p>This was a great instructable, infact im building it myself, the one thing that annoyed me though, as this was my first time building a quadcopter, i didnt have the parts that werent included in the parts list, which made me pay for more shipping because i needed more parts, These parts were the threadlock, the XT60 connectors and the prop balancer, For others that are/were in the same situation as me, you should add those to the parts list, will make thier life much simplier, as im stuck waiting for threadlock and a balancer now...</p>
<p>Boy what an interesting project ! Now where does that neighbour stay that skin dip on Saturday? </p>
<p>I'm going to build this but was wondering what kind of camera did you use??</p>
<p>I use a Contour ROAM Model 1600.</p>
<p>thank you for the info and quick response! :)</p>
<p>Awwww, thought this was going to be a taxidermy quadcopter made from a dead cat. Good of you to show the crashes, most people pretend they have none.. got a nice vid myself, lots of bits of desimated copter flying past the camera.</p>
<p>Nice Build and well written instructable. I plan on building a defib. deadcat soon. I found youtube videos from HobbyKing setting up the KK2.1 for the sk450 DeadCat frame. There are several other videos they do on the KK boards as well. It is ALL about the firmware on the board (I would NOT recommend you fly stock firmware) and the set-up, calibration and tuning of the board. Nice thing about the KK board is the screen and user interface. There are tons of them out there and just as many videos and guides for set-up and tuning.</p><p>Cheers! :) and Many Happy Flights</p>

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