Saturday, May 26, 2012

Andreas builds us a a pair of F22 Raptor foamies

 So Andreas saw the Flitetest video on the F22 and got the mood to cut out one for himself.  He called me up and asked if I had any 9mm EPP foam.  I did, and all the electronics and hardware necessary, courtesy of my prior thought to try to get the scouts to build some planes.  I was thrilled to be able to put these to use, and Andreas said he would cut out an extra one for me.   Here's the pieces cut out.
 And now glued up.  Very nice!  That's an 8x4 prop on a 1500 kV blue wonder motor.  18A ESC, 500 mAH 3S batteries, 9g servos.
 View from the bottom.  Those are 3mm carbon tubes running laterally.  Bamboo skewers on the leading edge and for the push rods.
 Here's mine, ready to glue up.  Using Beacon Foam-Tec, including the hinges.
And completed!  Elevon flight controls following the new East Bay Elevon standard, coming up in another post.

Flight test upcoming!  It will be fun to be flying something that only has two CPUs on board.

Here's the thread and plans by original designer dekan.

Friday, May 25, 2012

Building ArduPilot Mega on Mac

Here how I set up Arduino to compile ArduPlane and ArduCopter on the Mac.

Install Arduino

Download ArduPlane and create a working directory

  • Get the newest copy of Arduplane from the Ardupilot repository.  I grabbed version 2.34.
  • My home directory is /Users/mh, and my working directory is /Users/mh/apm
  • Change to the working directory and unzip
  • You should see these directories.  There's some others that you can ignore.

Connect your APM to the computer via USB

  • No kidding, the props can spin up unexpectedly and send you to the hospital for stitches!

Run Arduino and configure the environment

  • Run the Arduino program.  Restart it if it was already running so that it can see the APM USB connection.
  • Set the CPU type: Tools / Board / Arduino Mega 2560 (AtMega 1280 for APM1)
  • Set the APM serial port: Tools / Serial Port / /dev/tty.*usb*  The name will vary, look for tty and usb.
  • Set the sketchbook location:  Arduino / Preferences... / Sketchbook Location
  • Set it to the unzipped directory; In my case: /Users/mh/apm/ArduPlane-2.34
  • Quit Arduino and Restart.
  • Double check that the above three settings are still good.

Compile (Verify) the ArduPlane software

  • File / Open... and navigate to /Users/mh/apm/ArduPlane-2.34/ArduPlane
  • Open ArduPlane.pde.  This will give you a window with several files opened in tabs.
  • Click the Verify button.
  • After a while, you should get a message like "Binary sketch size: 157,232 bytes (of a 258,048 byte maximum)"

Upload to APM

  • Click the Upload button.
  • You should see the APM serial light blink furiously
  • You should get the message "*******"

Working on the Arducopter software

  • note: There's some unorthogonality with the downloaded Arducopter zip file.  There's no intermediate directory with a version number.
  • Grab the newest copy of ArduCopter from the ArduCopter repository. I grabbed version 2.5.5.
  • Unzip  in some scratch directory.  This will give you two directories, Arducopter and libraries.  libraries is identical to the ArduPlane version, so you can ignore it.
  • Delete the directory ArduPlane-2.34/ArduCopter
  • Copy ArduCopter to ArduPlane-2.34.
  • You should see the directory ArduPlane-2.34/ArduCopter.
  • In Arduino, open the file ArduPlane-2.34/ArduCopter/ArduCopter.pde.
  • Compile and Upload as described above!

Working with git

  • The Arduplane projects are hosted on Google Code.  Get a Google account if you don't have one.
  • Instructions for checking out are on the ArduPilot source page.
  • You don't need to grab ArduCopter separately.  It will be in the ArduCopter directory as described above.  If you do grab it, it will have a single file pointing you to the ArduPlane repository.
Using command line tools
  • There are notes in README.txt
  • tl;dr: cd ArduPlane; make configure; edit ../; make; make upload
  • I had to edit the following entry in libraries/AP_Common/ to add the -C parameter.
upload: $(SKETCHHEX)        $(AVRDUDE) -c $(UPLOAD_PROTOCOL) -p $(MCU) -P $(PORT) -b$(UPLOAD_SPEED) -U flash:w:$(SKETCHHEX):i -C /Applications/

Thursday, May 24, 2012

Zephyr II and ArduPilot Layout

Here's a few notes by Andreas on laying out a Zii with an Ardupilot Mega.

This is his first Zii.  One 5000 mAh 3S or one 3000 mAh 4S battery is placed sideways at the nose.

In his second Zii, he started with a plywood battery box.  He cut this himself; it's sized to hold two 4000 mAh 3S Turnigy Nano batteries.

To keep the radio components separated, he:

  • moved the video transmitter all the way to the winglet
  • put the RC receiver is in the center of the wing on the opposite side
  • put 3DR radio close to the APM in the main compartment
He mounted the ESC above the APM.

Tuesday, May 22, 2012

Aerial view of KGO interview

We had a nice interview with KGO San Francisco today.  Flew the quad and Zii in some pretty stiff winds -- there were whitecaps on the Bay when I was leaving.

For one of the segments I put the quad in position hold behind me, and answered the interview questions while holding the radio.  I was impressed with the position stability given the high wind.

Here's a snippet of the interview,  drone's-eye-view:

Sunday, May 20, 2012

Zeiss Cinemizer goggles

Here's the upcoming OLED Cinemizer goggles.  Close to $1,000, definitely nice looking... but too bad, they only go to +5 diopters.  I shall use them as style inspiration for my homemade set!

Wednesday, May 16, 2012

Some East Bay Magnetic Declination Numbers

Because you never know when you'll need them!  From

Location   Latitude        Longitude        Declination
BERKELEY   37° 52' 18" N   122° 16' 18" W   14° 7' EAST
PIEDMONT   37° 49' 28" N   122° 13' 50" W   14° 6' EAST
CONCORD    37° 58' 41" N   122° 1' 48" W    14° 6' EAST

Monday, May 14, 2012

Andreas' Heavy Lift Quad Tests

Missed posting this a couple of weeks ago...  Two lift tests by Andreas, 4 lbs and 8 lbs.  Pretty impressive!

Zii Battery Tray by Team Blacksheep

Trappy explains:  "the battery bay is there to make your ZII durable. on our tests we dived in vertical from 30 meters on purpose. the forces get spread evenly and the 6mm plywood takes most of the beating, protecting the battery and the ZII. Use lots of gorilla glue when glueing it in, the glue will enter through all these tiny holes in the ZII Bay and make it really strong."

Product page here, forum discussion here.  Lots of detail from Trappy, be sure and check it out!

Thursday, May 10, 2012

Thursday Miscellanea

When I started this blog, I made it a point that it would be mostly my own words.  If it weren't something I was actually doing myself, I would write at least a little about whatever it was I was posting a link to.

As a result, I often have a half-dozen or more browser windows open to various interesting things, waiting to be written about. I think I'm going to start a weekly post to collect these things.  I'll try doing every Thursday evening, based on the logic that I've got a few things open now and it's Thursday evening.

Monday, May 7, 2012

Imperial Screw Sizing

So I was trying to make a mount for my new Sony cam which has pre-drilled M2 (2mm) mounting holes. Just the wrong size for a 4-40 standoff!!!

Here's the formula for Unified threads -- those are the ones with a #1 - #10 at the front.

    major thread diameter = 0.060'' + (0.013" * N)

The second number (i.e. 40) is the number of threads/inch.

So a #4-40 has a major diameter of 0.112", or 2.8448mm.

Build-a-Quad Kit

I received a couple of emails asking about building a quad, and how much it would cost in parts to do it yourself rather than buying a ready-to-fly model.

Here's a HobbyKing based shopping list.  I think it's pretty feasible, a lot easier than building a plane since there's no moving parts.  You will need some basic soldering to put connectors on the speed controller.

Executive summary:  quad parts, about $230 including shipping.  radio and charger, about $100.

Frame and Power Distribution.  There's a lot of latitude in the frame.  You can make one out of old boards and plywood for almost free.  This is a popular frame and good for a first unit.  The power distribution board lets you easily hook up the speed controllers to the battery. 

      $20   Hobbyking X550 Glass Fiber Quadcopter Frame 550mm
      $ 4    Hobby King Quadcopter Power Distribution Board

Power System.  This includes the motor and motor controller.  You will need four of each.  The NTM motors need an accessory kit for mounting (thanks to Andreas for catching this!)
      $40   (four) HobbyKing 20A BlueSeries Brushless Speed Controller
      $64   (four) NTM Prop Drive 28-26 1350KV / 310W
      $ 8   (four) NTM Prop Drive 35 Series Accessory Pack
Control Board.  There are lots of options for control boards.  This is one of the simplest and cheapest.  It's good, but doesn't have stabilized mode.  It's what I started with, except when I bought mine it was $150!  See below for other options.  You'll need the programming cable if you ever want to update the programming.
      $20   HobbyKing Multi-Rotor Control Board V3.0 (Atmega328 PA)
      $ 5   USBasp AVR Programming Device for ATMEL proccessors

Batteries.  If you're in the US, it will probably be cheaper (counting shipping) to order separately from the US warehouse. You will probably want two to begin with.
      $19   Turnigy nano-tech 2200mah 3S 35~70C Lipo Pack

            Turnigy nano-tech 2200mah 3S 35~70C Lipo Pack (USA Warehouse)

Props.  You need two each "normal" props and two each "reverse" props.  It doesn't hurt to get an extra bag of each, as they are the thing which you will break most frequently as you learn to fly.

Connectors.  If you get the motors and power distribution board above, you will need two packages of this connector for your speed controllers.

Shipping.  I'm estimating about $30-$40 or so for all of this.

Other items you will need.  Once you have a battery charger and radio you are good to go on the ground side.

Battery Charger.  These come in all sizes and price ranges.  These are three units that I have personal experience with.
      $12    Turnigy 2S 3S Balance Charger. Direct 110/240v Input

             At the low end... plugs into wall, works well but wil
             take about 4 hours to recharge the batteries above.

             Needs to be plugged into your car or an external
             12V power converter.  Will charge in about 1.5 hours.

             Needs to be plugged into your car or an external
             12V power converter.  Will charge in about 30 minutes

Transmitter/Receiver.  Tons to choose from.  The 9x is a nice low-price unit.  It comes with a receiver; extras are about $10 each.  You want a "mode 2" which means the throttle is on the left stick.  These are frequently on backorder.  The Internet believes there's a new model coming.

      $55    Turnigy 9X 9Ch Transmitter w/ Module & 8ch Receiver

Camera Mount.  This one is designed for the X550 above.
      $13    Hobbyking X550 Glass Fiber Tilt Camera Mount

Sunday, May 6, 2012

Awesome Hex by Andreas!

 Andreas made a Hex today!  He started looking at it a couple of days ago after doing some weight testing on his Quad.  He's posted some notes over at diydrones.  Total frame cost, about $10!  He printed a cutting guide on paper and glued it to the plates for a cutting and fitting template.  Here's the arms glued into the two plates.
 Fitting the power distribution.  Note that he's bolted the arms as well.  It uses two batteries, each powering three motors in a triangular arrangement -- hopefully a power system failure will allow the three remaining motors to get the unit to the ground without a smashup.
And later that evening, it was ready to fly.  This is why it's so much fun hanging around this guy!!

Tuesday, May 1, 2012

RCTimer ESC's easily flashable

There's a nice RCGroups post showing that the RCTimer ESCs are easily flashable, withe the pads conveniently aligned on the edge of the unit.  They use tgy.hex.

Humor Break

I think a lot of readers will identify with this!

"One day, son, all of these perfectly good A.C. adapters, which have long outlived teh products they were originally designed for, will be yours."

Not sure of the source, somebody sent it to me...

Miles of Free Servo Wire!

Here's a thread I started on RCGroups, verifying that ethernet cable was a good source of 24 gauge wire.  It is!  There are 8 wires (4 twisted pairs) in each cable.  Make sure the wires are stranded and not solid, and you've got all the wiring you need, albeit in rather pastel coloration.

For me it's OK, I'm using it to make some custom receiver/APM connectors.  I'll make pin 1 be the odd color on each side.

I use this great servo crimp kit from Hansen Hobbies.

The plastic part is sold as:

Harwin M20-1061200 12 PIN SIL HOUSING

The "12" in the part number goes from 01 to 12, and indicates the number of slots.  I found the best value is to buy the 12 slot units and trim them down to size.  They cut easily with a box cutter.

LiFe battery in a 4x2x2 battery compartment

 Somebody on RCGroups was asking about how LiFe batteries fit into receivers with a 4x2x2 battery compartment, similar to what's on a Turnigy 9x.  Here's some pictures of how it fits (summary: just right!).  There's no stress on the battery compartment cover when snapping it on, and just enough room for the wires.  Use the power connector that looks like a servo connector.

HobbyKing 1500mAH LiFe 3S 9.9v Transmitter pack

It fits nicely in this configuration, but the 9x power connector is blocked.  This may or may not affect you depending on your receiver's connector configuration.