May 2015

EBRC Simply Cheap Quad Build

In this little project we will build a very capable and versatile quadcopter for around $250 in parts not counting a radio, receiver or battery. I know that we can find less expensive parts but the basic quad build will be the same.  For this project will use:

Ø  Flite Test ElectroHub Quadcopter Kit- $38 (Incl. power distribution board)

Ø  NAZE32 Acro Flight Control Board- $25

Ø  4- RCMC 2208 1900KV -$26.00 ea

Ø  RCMC 30Amp SimonK ESC -$18.00

Ø  Baseflight Software for programing the FC and ESCs.- Free & very easy to use.

Ø  4- 8x4.5 props 2CW, 2CCW

Ø  Optional- Angle Arm Brackets (Electrohub)-$10.00

The RCMC products come from http://www.buildrcdrones.com/index.html based here in the Bay Area. I also use MulitRotorSuperStore http://www.multirotorsuperstore.com/ also in the Bay Area. Prices are fine, products work, shipping is local postage and great support.

Keep in mind that the items purchased above can be moved to any new airframe in the future as these items will most likely not break in a crash, except for a prop or two. Maybe one of the ½ x ½ inch wood arms easily replaced at OSH or Home Depot. (Sanity Check#1: On maiden flight I threw a prop. The only casualty was a broken arm and a two props.)

You can buy ARF quads everywhere these days but the EBRC Simply Cheap Quad is completely repairable, programmable and supported by ME and others in the club. Plus, you have the personal satisfaction of joining the DIY Drone Revolution.

Our finished quad will initially be very stable and gentle on the thumbs. However, by changing a few parameters in the Baseflight config, we can have an exciting 3D flier. It’s a goal!

I have built a few DIY quads now and for this build I also suggest checking out the Flite Test YouTube ‘Electrohub Build’ video. https://youtu.be/c5yXm_PJxK0

Before the build, let’s discuss the NAZE32 Acro Flight Control Board. There are a few good flight control boards available such as the KK2 board and OpenPilot CC3D. (JD uses NAZA.) Tim and I have experience with the NAZE board and I would suggest using the Acro allowing us to better trouble shoot if necessary. Also, if you wish, I will give you a pre-programed RTF Acro with pins soldered in place (a little tricky) for an exchange with a new packaged one. Easy for me to do and might greatly move your project along to that maiden flight. I think that you should be able to build this quad in a few hours. A few screws, a little simple soldering, some zip ties and just maybe, a little Velcro and BAMMMM!

Let’s begin the adventure.

I always like to layout all of the project’s parts on the table to visualize how they will play together. (Kind of that ‘Mise en place’ thing encouraged in culinary schools’)

Here are the pieces to our quad.

Begin by placing a few reference lines on the lower body bottom plate which is also the power distribution board. First mark the front of your quad. I used a silver Sharpie to draw an arrow indicating my quad’s front and a couple of lines indicating where the four legs will attach. (I am using an X configuration though there is a config called ‘dead cat’ shown in the Flite Test vid.)

Next we’ll line up the holes to drill in the wood arms for attaching to the hub.

At this point we can get out the solder and soldering iron because it’s time to attach the ESCs to the lower bottom plate which is also our power distribution board. This board makes for a very clean and simple wiring harness. The fewer wires on a quad the better.

Here is a simple diagram of the layout for each arm.

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Prepare each ESC for soldering to power distribution board.

·         Un-solder all motor wires from ESCs as we will wire motors directly to the ESC. This step makes a much cleaner build and no chance of connectors coming loose when you run the quad into your neighbor’s house.

·         To do this, you must trim shrink wrap back from the ESC to get to the lead’s solder joints.

·         Next, trim the power wires to properly attach to the power distribution board. Tin each power wire thoroughly to insure no ‘cold solder’.

·         Build a battery connection wire and plug as well.

Do you have something that looks like this?

Now solder the ESCs and the battery connection to the power distribution plate. (Lower plate.)

Again, if you have been paying attention, you will have a similar board in front of you.

A couple of things to keep in mind.

·         Remember that the wood arms need to fit flush with the plate. You can see here that I had to solder the power leads facing away from where the arms will sit. You might want to wire differently. (I did have to trim a little off the bottom end to a couple of arms.

·         Remember that when you solder on the battery connection it should be at the rear of the quad. Also, I brought the wires through a plate hole thus reducing the possibility of tearing off the battery leads when doing a double Immelman. (Remember that Sharpie arrow that you made in Step1? This is not the last time that you will appreciate that arrow.)

Note: If your board looks exactly like this one you are in for a real treat. You see, there is a dead sort wired onto this board. Smoke test alert; that short took out one of my ESCs and my FC. Damn!

With that note, this would be a good time to plug in a battery and give the board the ol’ spark test before you connect your FC and Rx.

OK, now we can install the four arms and attach the top hub plate.

You might notice a slight change in my build. That’s correct. I morphed my wood into carbon fiber. (Just kidding. Black paint.

You also might notice that my arms have braces screwed in the middle. Remember at the beginning of this document that I mentioned the optional angle arm brackets. Well, they are installed on my build at this point. Here is the appeal of the angled arms.

A couple of notes.

·         Make sure that your 3 wire control leads are available to the top of the assembled hub because they will be inserted into the flight controller that will sit on the top plate as will your Rx.

·         Fitting these two plates, four arms and eight bolts together will test your patience. I highly recommend Lite Beer for this procedure.

Here is a close up of one of the ESCs mounted.

 

As you can see, we are getting very close to having a flying beast. At this point in the build, I suggest drinking the remaining Lite Beer and switching over to Jack Daniels and calling it a day. Ok, that’s just me. (Of course, thinking that you could build this in a few hours was silly.)

Good Morning Bright Eyes.

Next step? Mounting the motors and soldering on the motor leads to the ESCs. There will be some interesting nuances to this as we need two clockwise rotating motors and two counter clockwise rotating motors. And, we need those motors to be in the correct locations or our little flying project will heartlessly, and quite violently, flip over and break two props upon maiden lift off.  Been there! Tee shirt please.

Let’s start with mounting the motor. The kit came with 8 ‘motor mounts’ cleverly disguised as little flying saucers. Before you get your undies in a bunch, this is how these work.

Side note: Some suppliers ship motors with two types of prop adapters; clock wise and counter clock wise. RC Manchild is such a vendor. Here I have both shown as indicated by the prop nuts. The appeal is that these prop nuts will not spin off.

You actually don’t need to order motors with these different threads and I won’t again. I find that throwing these prop nuts as far away as possible is just fine. I prefer to use all CCW (Silver) adapters and nylocks on motor. (This would be standard threading.)

Now, if you have a motor set such as mine, you have some homework to do. If you are using a NAZE32 FC your CCW motors will be at the 2 o’clock and seven o’clock position. I don’t know about other FCs. (We will have more on motor rotation when we hook up the FC and the Rx.)

Now, where were we? Oh, yeah.  We can now solder the motor leads to the ESCs.

Though we know that we will need to have two motors rotating differently, go ahead and solder each motor identically to their ESC. We’ll re-solder two of them later. After all, you have a 50-50 chance of them being wired correctly which means that 85% of the time you will be wrong.

At this point you should have a nearly complete EBRC Simply Cheap Quad.

However, you may have noticed that the build has taken longer than the ‘few’ hours quoted on page 1. Oh well, it was just a goal. That setting the bar high thing. Aim high, hit high. If you aim at nothing, you'll hit it every time.

There you have it. Wire the baby up and go flying.

Oh, you are missing a few steps? Thought this was a HobbyKing build manual? Nope. We still have a little work to do Grasshopper.

The following steps relate to the NAZE32 board, Spektrum Rx and Baseflight software. I simply don’t know about other electrical configs with different FCs or different radios.

In regards to the NAZE32 FC, again, I will configure an Acro for you. If you want to do this yourself, I recommend:

https://youtu.be/ozwkaenbGUM

https://youtu.be/rj6IXA2hDW0

And/or, Chris’ terrific step by step in the Armattan tutorials. http://www.armattanquads.com/mullet-naze-fc-tutorials/

Skipping ahead. Let’s complete this project. To recap, we have everything bolted down EXCEPT THE PROPS! You have followed my perfect directions like a first grader crossing the Main Street and we only need to install the flight control board and the receiver. Right?

Before we do that, plug in a battery and see if anything catches fire. (Idiot! You did what I did. FUBR.) No smoke? Time to move on.

Like all flight control boards, the NAZE32 FC has a few basics to work its magic. It needs power from the ESCs, control of the four motors and instructions from you through your radio/Tx.

The four motor’s control leads plug into the FC. That takes care of power and the FC control of motors. All that the FC needs now is timely instructions from you radio via the Rx. That is accomplished with a simple wiring harness between the FC & the Rx.

This wiring harness in most DIY quads is slightly different from the conventional fixed wing setup. For our NAZE32 FC we will use a typical 3 wire servo connector (Signal-Power-Common) to bridge the FC and FC at the aileron Rx slot. Now we have power and common to our Rx. We only need signal wires to the other servo connections on the Rx. Most flight control boards will include this wiring harness.

Here is that harness attached to a FC. See the only 3 wire bundle? That is attached to your aileron slot on the Rx. (The empty pin set at 9 o’clock is for our motor ECS leads.) Friggin piece of cake Dude/ettes!

At this point, I am going to stop. Again, if you are using a NAZE32 FC and Spektrum, I will be happy to set up your quad right at the field.

Let me know if you have questions or get stuck on your build. I have made a lot of mistakes in the past six months building quads, so go ahead and try and stump me.

Oh, and there will be some setup issues for your radio. For me, using the NAZE32, all throttle ‘end points’ are set to 125% except throttle which is at 110%. Reverse aileron & rudder. We will also need to trim up aileron, elevators and rudder in the software.

If you want, all the software, ESC and radio trimming can be done at the field on one of those lovely white tables. I’ll bring the coffee.

Time to Lewis & Clark the mother!

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