DJI Naza F450 Flamewheel Assembly
I can hardly call it a build log. The DJI Naza with the ARF F450 kit goes together in no time at all. The most time consuming part would have to be soldering the ESCs to the main board and that isn't very difficult with the well marked and laid out bottom board. The solder joints to the ESCs are bare and exposed so to prevent any inadvertent shorts, I used hot glue to insulate the connections.
- The kit comes with a couple of wires for you to solder your favourite type of battery connector to the main board with. Before insulating those connections, I also soldered the connections from the Versatile Unit (VU) to the same points.
- ESCs are cable tied directly to the frame. Just connect the three motor wires up any which way and test them for the righ direction later. You've got a 50/50 chance of getting it right.
- I mounted the Naza dead centre in the middle of the bottom board with the supplied foam tape. I ran the wires to the receiver through one of the holes and mounted the receiver on the bottom side of the bottom board. This was purely to reduce the clutter of the wires.
- I mounted the VU also on the bottom side of the bottom board. the idea here is that the VU LED displays important infomation by varying the colour and frequency of the flashing light. By mounting the VU there, as long as the quad is above eye-level and right way up, the light should be visible to the pilot.
- I didn't balance the props. I probably should but I stuck them straight on and I get great results anyway.
- Programming is fairly straightforward with the DJI Assistant software. One thing to take note of, initially I experimented with the X1 & X2 remote gain settings by assigning them to channels 6 & 7 on my Tx. I mistakenly increased the gains to maximum and on the first couple of flights, I was a bit disappointed with the vertical hold. It tended to drift up or down and compared to all the youtube videos I've watched, it was very disappointing. After checking the gain settings, I set them the same as "stockfoodpics" from youtube because he's using exactly the same equipment as me and getting great results with video from his GoPro camera. The settings are "Basic: 150 150? 100 120 & Atti: 70 70 "
Unpacking the Naza Controller
After 3 years of using a couple of MultiWii Paris boards (Version 2 & 4) on a whole variety of quads and tricopters (http://bit.ly/JZ1iDA) and tricopters, I've bought my first commercially made multirotor controller. The DJI Naza controller (http://bit.ly/JZ1S4r) along with an F450 Flamewheel frame. It's tempting to retrofit a couple of old Quads with the Naza to compare the performance between the MWC and Naza but I'm too keen to see the DJI controller and frame flying as one unit.
What comes in the little red box.
- The Main Control unit (MC). It's smaller than I expected with inputs at one end and outputs at the other
- The Versatile Unit (VU). Basically a voltage monitor, regulator and USB interface to programming the board.
- The USB cable. I was a little disappointed it uses a micro USB connection instead of the fairly standard mini USB connection. It just means I'm less likely to have a spare cable on hand if I misplace the DJI supplied one. I guarantee if you were at the flying field and needed a 'mini' USB cable that almost every product comes with and seem to be multiplying in my desk draw, someone would have one in their camera bag or portable hard disk....
- 3-PIN Servo cable (female to female) for connecting your receiver to the Naza controller. By the time you connect the four standard controls, plus mode switch, plus X1, X2 & X3 you'll use them all up.
- 3M Gummed paper for sticking the controller to your multirotor. It's not very thick. Not sure if I'll use the supplied stuff or my own.
Configuring the Naza.
- The first thing to do is download and install the DJI Naza Assistant Software. Registration and activation by email is required so the DJI overlords can keep track of everyone that has the privilege of using their hardware.
- While waiting a few seconds for the activation email I soldered an XT-60 connector to the VU and hooked up a 3S 2200 Lipo.
- I'll be using 'Quad-rotor X4' config.
- Receiver Type = "Tradition(al)"
- Calibration was pretty straightforward by banging the sticks to all possible end-points. At one point I did get a flashing red box saying "Config Error" but after a power cycle it went away.
- I've assigned Sticks monitor (X1 & X2) to my slidey switches on the LHS and RHS of my Futaba 10C Tx. From what I understand these channels can be used for inflight gain adjustment. I'm not convinced I'll use that much but we'll see.
That's about as far as I've got. Think I might start putting the frame together.
Spider Quad test flight
It was looking good with the FY-91Q control board until the Spider Quad dropped out of the sky (well maybe only about 1 foot off the ground). Looks like the 3mm Bunnings ply maybe wasn't up to the task. Easy fix though, I'll mount the motors directly to the aluminium c-channel. The wooden mounts are superfluous anyway.
Spider quad build
The motors, ESCs, and control board (FelyuTech FY-91Q) board are all mounted. Now I just need to connect them all.
Just mucking around with this control board while waiting for the DJI Naza to arrive.
How to connect 4 ESCs to one LiPo battery (Make a power distribution board)
The first time I built a power distribution / wiring harness for a tri / quadcopter was back in December 2010 (http://fangin.com/blog/2010/12/07/tricopter-build-wiring-harness/) and I chose the most direct solution which was to solder all the cables together. I say "most direct solution" because in hindsight, it's not the simplest solution. The drawbacks of this solution include;
- It's more difficult to layout all the wires and get the lengths planned up front.
- Twisting the wire together and soldering 4 or 5 wires at one junction gets messy.
- I tried to link all the wires at one point (http://fangin.com/blog/wp-content/uploads/2010/12/1000000286-Large.jpg) to go into the battery which made it difficult to get the wire into the XT60 connector.
A neater, simpler and all round better solution is a power distribution board where a central, double sided PCB board (copper on both sides) is located centrally in relation to the ESCs / motors and all the wires connect back to this PCB.
What you'll need.
- PCB - Double sided.
- Cutters
- Red / Black Wire
- Solder / Soldering iron
- 20mm heatshrink tube.
- Cut a small board approximately 35 x 15 mm of the double sided PCB.
- Prepare the wires and board by soldering the ends of each wire and the board where the wires will go. You may want to consider orienting the wire to suit the layout of your multirotor. For example an X-Quad you may want to have four wires coming off the board in an X layout.
- Solder the wires to the board. Turn the board over and repeat for the other polarity wires.
- At this point you're almost ready to seal the board up with some heatshrink tube. Before you do! Use a continuity test on a multimeter to ensure 1) All the ground wires are connected and 2) There is no connection between the positive and ground planes.
- If you're worried about wires moving or foreign objects getting into the heatshrink, smother both sides of the board with glue from a hot glue gun. That will help keep the wires in the right place and prevent a short circuit between the two polarities should something conductive work it's way into the housing.
- Now you can solder your favourite connectors at the end of each pair of wires. In the photo shown below I've used XT60 connectors on a harness made for a tricopter.
Proof the foamy quadcopter flies
Today was the first flight outside the confines of the garage. It was quite windy at the local oval making it fairly difficult to maintain stable flight. It's not meant to fly nicely, it's meant to look weird and fly weird and that's exactly what it does.
GoPro Time Lapse Setup
The problem: I want to record still images for a few hours with my GoPro camera using the suction cup mount and waterproof case but the battery is flat and I have to start recording in the next five minutes.
The solution: Drill out the side of the waterproof case where the USB cable would normally plug in. Now with the camera mounted in the non-waterproof case, on the suction cup, I can plug in the external power source usin a nano-tech 2650mAh battery. I know you can the skeleton housing with the sides cut out but a) I need a solution now, b) the skeleton housing costs just as much as the waterproof housing and c) Most of the stuff I do doesn't need a waterproof housing anyway.
Turnigy Model Be Found
Going by the name of the Turnigy "Be Found" device, I get the impression it supposed to help you find your model if in the event of a mishap, it goes down somewhere hard to find. I've got a number of issues with this which I'll outline below. But then take a look at the website description (http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=20578) and it describes it more as a pre-flight safety check device to audibly warn you if either your battery voltage is low or you lose the radio link during the pre-flight check you do before every flight (right - every flight).
From the website:
"This Handy unit will emit a loud beep if your receiver loses radio signal or when the voltage of your models radio system drops below 4v. Perfect for testing ground range of receivers and ensuring that your radio system has not dropped to an unsafe voltage before each flight."
Let's assume the low voltage part of it works (I'll have to assume because I didn't bother testing it), let's take a look at the worse case scenario where the model is lost in-flight and has to be retrieved in thick bush. Here are the drawbacks and why I reckon it won't work;
- It didn't beep when I switched my Tx off. That's a pretty drawback as number one. Am I doing something wrong? Check the youTube video for how I tested.
- Of all the models I've seen crash, the battery pack is quite often not connected to the receiver anymore (ie no power to the buzzer).
- I reckon it introduces another likely point of failure. The in-line connector for the servo was a bit dicky and bent and the plastic cover stopped me from plugging it in properly the first time.
- If I have to rely on the low voltage buzzer to go off while I'm searching for a lost model, I could be waiting a while for the pack to drop below 4V.
- Even as a pre-flight check device, if I'm standing 10-15 meters away from my model at a busy club field, and it did start beeping, I'm not convinced I'd hear it.
Overall, as a safety device, I don't think it adds much value and your radio setup is probably better off without another point of failure being introduced (even if it is only on one channel). This one is a Pass.
Using the HobbyKing servo tester to setup servo arms
Installing servos and getting the arms in the right position can be a pain if you haven't got around to setting up and connecting your transmitter yet. A servo tester like this one http://bit.ly/xUeoyB means you can find the centrepoint and test the throws all without the Tx. In the photos and videos below I've got three Hextronik HX5010 servos installed and pretty much centred without using any radio gear.
