There are a lot of home-brew parts in this machine (no fooling, really).
I had orignially fabricated parts based on the 'A' frame but after noticing the 'B' release, I ordered replacement parts and modified mine as close as possible. The bottom plate is 1/8 aircraft plywood painted. The top was made from an FRG piece I had in a junk box.
Getting access to the PDB is now much easier and if you have an 'A' and break it, go to the 'B'.
The legs are made on my home-brew CNC Dremel router.
Using the posted 3DR drawings, I made some G-code that cloned the 3DR leg pretty close. I didn't bother with the nice radius at the 'foot' end but may tinker with the code later. The harvested circuit board material found new life rather than being tossed in the landfill to decay over a thousand years. This way I get to break it in spectacular fashion!
I used 6-32 screws and remachined some aluminum hex standoffs I had for the leg hardware. I let the CNC router crank out two complete sets of legs as I suspect a few will get broken while I earn my quad wings.
Using what I have in my shop/garage and buying significant parts from 3DR has been my approach.
Things left to do/make are:
- Electronic stack plates - I may go with 1/8 aircraft ply. I have to make G-code for this.
- Optimizing the wiring and completing the connectors
- Weight reduction - perhaps some material off the arms beyond the leg mounts?
- Ebay stuff to fund the APM and the rest of the electronics.
More to come!
April 14, 2012
I've been assembling the PBD, ESC and motor connectors.
I went with the XT60 for the battery side rather than the Deans.
After routing the motor wiring as mentioned previously, I added another layer of heat shrink to the wiring to provide another level of anti-chaffing.
For those of you interested in the actual hole pattern on the arm...
As this is my trainer quad, as mentioned before, I think the next arm will have radiused corners out past the motor. This will reduce impact edges and give the arm a more finished look I think.
Here is one of the arms with the extra heat shrink at the motor, the ESC with all connectors zip-tied in place.
I took the Arducopter, prior to mounting the just shown wiring updates, to one of the local shops in Greenville, SC, The Great Escape. Keith is the resident heli-nut and we discussed the need for me to spend time with a simulator. Real Flight 6 Heli now has a quadrotor in the selection. The in-store demo unit had me hovering and breaking props in between reset button presses. It looks like a great product and at rev 6, it seems that it won't be going away anytime soon.
Keith inquired about the PDB and had not heard of 3DR. A quick trip on one of the store's PCs to the DIYDrones Store and he was in love with the Hex copter. I tried to explain the APM and its open source development. He was accustomed to a single threaded application (dumb controllers) rather than a 'smart' controller like APM.
We had a good visit for about an hour or so and I promised to return when the Arducopter was getting closer to flying.
Before I get the funds for the APM order, I may build a servo 'stimulator' and check the motor directions. Anyone ever try that before bolting in an APM?
May 19, 2012
Checklist items acquired for the quad:
- Spektrum DX6i (with DSMX) an ebay win
- AR6210 receiver with sat receiver for above
- Cable allowing the DX6i to operate FMS sim software
- Been practicing with an FMS quad model - the only problem, it does 3D! INVERTED HOVERING!
Still building funds for the APM2 purchase. I gathered parts for the servo stimulator and need to get that sub project going. I may just breadboard it and then used one of my favorite programming languages - solder.
Comments
Very nice, specially the easy access to the PDB, good job
good project,
i built a hex exactly the same ali square arms using 2mm carbon plates for the middle have a look at my photo gallery.
regards
Steven, the arms are only dimensional 0.75 square aluminum from a DIY/home improvement store. This stuff is usually found in the hardware section but.. be forewarned that it isn't cheap either. I thinka 4 foot length of the stuff is around $16. If you use the version 'A' drawings located HERE you will see how much of the stuff you need.
The arm tubing is from some antenna projects gathering dust. It was still purchased from the same kind of store. Having a small mill and lathe in my tool collection made the machine work moderately easy. I did mess up on the frame mounting holes and had to adjust the frame plates to work with the machined arms. This stuff all takes lots of time to learn to use and get running.
I looked at many alternatives to building the quad and found that this site, and the folk that support it, were the best resource. The posting of the drawings was the clincher for me. My approach has been to use what was in the shop/garage and buy/source the same stuff you mention - motors, ESC, 'brains' etc.
I ordered a set of 'B' frame plates so that I could get the dimensions right on the next quad. The home-brew CNC router can make a leg in less than 10 min. While in that mode, two complete sets of legs were fabricated.
Ellison, Thank you. The next build may have a longer cable slot, possibly a plastic insert to prevent chaffing. The hole was made with a 4 flute 0.5" mill cutter. I filed the top edge a bit to take the corner off. As this is my first quad, and probably subject to much bashing around, it will be a work in progress.
Steven, have a look at my blog:
http://diydrones.com/profiles/blogs/first-flight-of-3d-printed-fire...
If you want to DIY, you can use TREX 450 tail booms. They are strong, straight, and light.
The arms and frame should cost about $70.
There are also wooden frame alternatives from Hobbyking:
http://www.hobbyking.com/hobbyking/store/__502__501__Multi_Rotors_P...
RD, nice build. Simple but effective.
Should put some rubber grommets where the motor wires are coming through.
Ruwan - Thank you. I had to make an alignment jig for the arm end that allowed me to mark the motor holes on the arm ends. It is a work in progress that will allow me to fabricate arms faster.
Andy - My thought exactly. The 3DR arm, an improvement over the initial Arducopter arms, still looked to allow the situation you described. Of course with practice, none of will crash our Quads... eventually.
The next set of arms I make will have radiused ends, rounded to the diameter of the motor housing, to reduce the chance of corner injuries though the diameter of the props are more a danger than corners. At the very least it will remove unneeded metal and look cooler.
pretty impressive way to mount motor. This way you can expect less deformation on the arm compared to having them on the center line. Cross section of my arms motor ends (from 3DR) are not square any more :-(
The wires are the silicone type that were provided (already installed on the motors) with the motors from 3D Robotics.
850 Kv Motor from 3DR
The arms were fabricated to allow a shorter wire length.
Rather than entering the arm from the outermost end (current 3DR frame), they enter from the arm top.
The motor mount holes are not centerline with the arm but angled.
This was required to allow the wires exiting the motors to align with the center of the arm.
I hope your question was answered. Thank you for looking at my project!
would you mind telling what wires did you use for the esc extension to the motor(the ones that go inside the arm)?
The legs are probably tougher than plain FRG. There are layers of copper foil, 5 layers I think, and the holes are full of solder. In between the foil layers is FRG. We will see how they hold up. The price was right.
My CNC is based on the (now out of business) Kleinbauer Brute. Unless you have access to some good shop tools, I would not recommend that device and already I could use a larger unit. I made this one with the intent to learn from it and use it to prototype circuit boards.
The controller is the other half of the unit. I used LiniStepper boards for the motors and built the entire thing into a rack mount style cabinet. I can use the controller on another router if I sell off the Brute.
The CNC hobby is a real time sink. The machine, the controller, and the software all have learning curves.
Regarding G-code, it is the programming steps/language that are used to drive the router motors. I use TurboCNC software. It is DOS based and free. There are several ways to back into/stumble into the CNC hobby. Plans and kits are abundant now. Several good books also exist to give a newcomer an idea of what they would be getting into.
In short, you have to ask yourself what is more important? Sole sourcing an entire project or enjoying flying the project? I am a maker at heart and had enough resources to build what I have. Each person's resources will differ.