Tuesday, October 30, 2012

DSM2/DSMX JR Module, Turnigy 9x Compatible

I've been looking for one of these for quite a while.  Spektrum had a JR-compatible DSM2 module, but it was almost $100.  But now HobbyKing has them for $30.

OrangeRX DSMX/DSM2 2.4Ghz Transmitter Module (JR/Turnigy compatible)

This is great news for anybody that has a Turnigy 9x transmitter and

  • loves Parkzone small flyers such as the Night Vapor and Champ (like me!)
  • like the orange receivers for their park flyers
  • Looking for a Tx/Rx pair with failsafe
DSMX binding example here.

Mine's on order, I'll update this space once it comes in.


The first batch sent by HobbyKing had a firmware bug.

executive summary:
  • it only affected the first batch that was sent
  • it's been fixed
  • newly ordered units are not affected
  • if you use er9x, you can work around the problem but can only use 6 channels
  • Ch. 2 is flaky
  • seems to be related to frame timing
workaround 1, if you have er9x:
  • tested against OrangeRX and Champ with built-in RX:
  • - on menu 1, set:
Proto PPM 8CH 200 mSec
PPM FrLen 20.0 mSec
  • - on mix menu, set
ch 1 100% THR
ch 2 -100% AIL (i.e. reversed)
ch 3 100% ELE
ch 4 100% RUD
workaround 2, only works with external Rx:
  • avoid Ch 2, route whatever would normally be plugged into Ch 2 into Ch 5
  • works if you have discrete Rx
  • of course, doesn't work with any built-in Rx since you can't change the channel options

Saturday, October 27, 2012

er9x Success!

Hooray, er9x installed and seems to work!  Attached is a screen dump of the   eePe settings.  I used the SmartieParts board, but didn't hook up the backlight... maybe later.

My contribution to the user docs:  Here's the parms I used. Also note: the SmartieParts board is USB powered, but the 9x CPU is not.  So turn on your Tx power!

provisional APM setup like this:

CH01   +100%AIL 
CH02   +100%ELE 
CH03   +100%THR 
CH04   +100%RUD 
CH05   -96% HALF Switch(THR)
       +90% HALF Switch(ID0)
       +45% HALF Switch(ID1)
       +17% HALF Switch(ID2)

Soldering Notes

Here's how I practiced my soldering.  I got some printed circuit boards and a bag of headers, and soldered 725 through-hole connections.  It took me a couple of evenings (not working very hard) and when I was finished I felt pretty confident in my soldering abilities.

These 5x7 cm prototyping boards from banggood are less than a dollar, including shipping.

Friday, October 26, 2012

Champ STOL flaps

STOL = "Slow Takeoff or Landing".  Makes the Champ fly even slower and smoother.  Alpert writes:
I made them myself out of 1mm depron. Simply cut 6 small obtuse triangles for each wing panel and glue a 1/2" (12mm) strip of 1mm depron so that you get about a 20* angle in each one. The Champ flies perfectly well without them but I like to experiment with stuff like that.

Wednesday, October 24, 2012

Walkera "Magic Cube"

Lets you transmit to a Devo Rx from a smartphone or from the older Walkera Tx.  It reads the PPM signal from the trainer port.  I'm hoping it might be usable from the 9X.  Not bad for $16.

At HobbyOne. Comprehensive review.

12-battery 1S SuperCharger Completed

Part 1 here.

The remainder of the parts came in, so I soldered up the connectors and elegantly hot glued everything together.  I've been using it for the last couple of weeks, and it's been great!
The Turnigy FC100 micro-heli chargers are the cheapest... at $2, they're less than half the price of the other flavors.
If you're getting connectors for a Walkera, be careful because there are apparently some other vendors that use the opposite polarity of Walkera.
Here's the charge leads soldered onto the tabs.
Totally now I've got 12 charging ports... four each of Eflight, Turnigy FP100, and Walkera.  There's still an open USB port as well!

Note: if you do this, be sure and check the power adapter provides sufficient amperage so that each charging unit can draw 500 mA.

Friday, October 19, 2012

Servo Anatomy, In Depth

A really great presentation.  He covers the usual PWM stuff (nicely), and then talks about the electronics inside the server, including how the controller works.  It took me a couple of weeks of self-study to get about 75% of the stuff he covers.

There's lots of other interesting stuff on the site as well.

Supplement: Controller magic is courtesy of the Mitsubishi M51660L.  Another great writeup is here.

Monday, October 15, 2012

ArctiBaby Update: Rather Sweet Little Quad!

After letting it sit around for far too long, I finally got the ArctiBaby tuned and flying.  I'm using my old MultiWii board.  For some reason, it's not able to sense the accelerometer, and something is stopping the config program from showing any sensor data, but the PIDs and other settings can be manipulated, and acro mode is working.

So, as I've been meaning to do for a long time, it's a great chance to practice Acro mode.  Hooray!  I've been flying it outdoors a couple of times a week, and it's really helped my piloting skills.  I need to fix it up with something that shows orientation because it's so small.  With stabilization it's not so bad, since you can let go of the sticks and  then experiment to find your orientation.  But in acro mode, you're tipped and headed sideways, so you've got about 1 second to figure things out before plowing into the ground.

And speaking of plowing into the ground, there are two weak spots on the arms.  I've busted two of the arms (hint: don't be tricked when flying over fake grass layed out over concrete.  It's not as soft as it looks!)  I patched them up with no problem, but if you get a Turnigy Microquad (which recommend!), reinforce the arms before you fly.  I've got some pictures of the repairs I made and will get them up in a following post.

Below is a video of how it's flying after my first round of PID tuning.  I've updated them a bit (increased P, decreased I just a little) and now it's more responsive and still rock solid.   Indoor flying is no problem, except that my son finds the motor whine excruciating ("way worse than the mosquito tone!").  I can't hear a thing of course, so I fly it in the living room when he's not around.  The motors are small enough that they'll stop if you stick a finger in the blade, so I'm not too worried about shredding the upholstery, etc.

 Upcoming: get the APM2.5 on the thing, and try some indoor waypoint navigation at the next Concord Model Engineers indoor fun fly!

Sunday, October 14, 2012

East Bay Maker Faire Demo

The Maker Faire was a great success!  There was a standing-room only crowd, Chris' talk was interesting and funny, the demo flight went well, and I had a great time talking to a lot of people interested in hearing more about our drone work.  The Charming Mrs. Harrison came along and took photos. After we finished with the demo we walked around and enjoyed the other exhibits as well.  I wasn't quite sure what to expect from a "Mini" Faire, but it was definitely worth going to.

Prepping the talk.

I brought some visual aids for the show-and-tell session.  It was a lot of fun explaining the basics.  Next time I think I might rig up a receiver attached to a motor and ESCs, and let people control them via the transmitter.
I brought the Arctiflyer VI (now with sweet sweet APM 2.5 power!) and the ArctiBaby.  In addition I brought the Zephyr II (five feet of flying wing awesomeness!) and the EZ-Flyer.  That was one of the first planes I built that actually flew, and I still love it.  Whenever I take people out to try a flight, that's the plane I use -- it's pretty invincible!  It's a great Maker thing as well -- about $10 of stuff for the body and $30 for the electronics, made from a free design posted on RCGroups.
 There's this awesome blog you should know about...

 Chris knows how to tell a story... I've heard how he got started as a drone maker maybe half a dozen times so far, and I was still hanging on every word.  I was standing to the side watching the audience, and they were equally engrossed.  If you haven't heard it yourself, check it out here.

 I gave an overview of some of the aircraft I had brought.  I thought the Arcticopter was another good Makers' Faire candidate, being constructed about halfway from remnants scrounged out of the recycle bin.
 People seemed surprised about the new generation of Foamy planes.  I think there might be a lot of fertile ground for new RC and Drone makers based on that.  I love my peeps in the Concord Model Engineers who make beautiful balsa aircraft, but this is definitely a lot easier to get started with.

Somebody has a new book, have you heard?  I received my copy in time to bring it in to get it signed.  So far I'm really liking it.  I love it when he compares the makers to the original Homebrew Computer Club guys.  They were my inspiration back in the day, and I worked really hard to get to Silicon Valley to follow in their footsteps.

After the talk, we went outside and I flew a demo flight.  It was in a really small space, and there were people on three sides, so I didn't do much more than bring it up and put it into loiter mode.  It was pulling a bit to the right.  Normally I would have let it move around and find its natural parking spot, but I nudged it back to the center so as not to go near any of the spectators.

 I'm not naturally a "kid" person (although I'm on pretty good terms with the two I produced), but I was pretty impressed with the kids that showed up.  They were careful in handling the planes, asked some good questions, and in general were really well behaved.  Maker Parents, take a bow!

Here's another view of the flying area, showing the distance between the quad and the audience.  The people in the picture above are to our right from this angle.  They were behind us as I was flying and Chris was narrating the action.

 Sure, go ahead and spin the prop.  The EZ-Fly is a tough old bird and has been through a lot worse!

It's not so often I'm totally surrounded by people wanting me to go on and on (I'm wanting so badly to say "droning") about RC and drones, so I had a great time.

Next time I'll have some blog post about how to get started in RC and Drones, since that was one of the most FAQ of the afternoon.  Unfortunately the East Bay has a dearth of RC clubs, otherwise it would be easy to point them in that direction.

If we chatted and you're still got some questions or are in any other way interested in the talk and presentation,  feel free to drop me a line and keep in touch... I love talking about this stuff!

Hello to East Bay Makers!

As mentioned a couple of posts ago, here's some details on what I'm bringing to the East Bay Maker Faire.

Arcticopter VI.  This is what I'll be demo'ing with Chris.  Here's a picture of it when it was the Arcticopter IV, two upgrades ago.  It's got an ArduPilot Mega 2.5 autopilot board, and RadicalRC mounts.  Everything else is homemade, in case it's not obvious.

The Arctibaby.  I built this model because I wanted something small I could fly indoors.  I've flown the Arcticopter indoors but it's a bit too loud and definitely non-friendly to lighting fixtures.  It's mostly kit built with custom reinforced arms.  It's currently got a MultiWii controller, but I've flown it with the APM, making it the smallest ArduCopter frame I know of.

The Walkera LadyBird.  This is totally store-bought, but it's a dream... small, agile, relatively inexpensive, and totally cute!  Everyone that tries one really likes it.

Ritewing Zephyr II.  This is a popular flying wing.  The ArduPilot makes it much easier to fly when using it for aerial photography.

EZ-Fly.  This is home-built out of sheet foam insulation, a popular building material these days.  It's from a design posted on rcgroups.com.  The RC community has a long tradition of sharing designs, DIY, assistance, and other Maker-isms that make it a nice group of people to build things with.  Video here.

Interested in learning more about what we're doing, and what exactly "drone hobbyist" means?  We've gotten some good coverage by the likes of NPR and the Wall Street Journal.  I'm happy to say that the reporters understood what we were trying to accomplish and did a great job putting together their stories.  There's some links here.

Want to learn more? The DIY Drones site is here.  I fly with the excellent fellows of the  Concord Model Engineers.  They've been around a while -- our most senior member started aeromodelling in 1938!

I've been contemplating an Intro to RC class.  Does that sound like a good idea?  Drop me a line and let me know at marhar@gmail.com.  Likewise if you're into... Drop me a note and say hello!

Nice Airbrush Paint: Glidden Eggshell Interior

Heard a great tip on The CrashCast about using the sample sizes from the paint store.  Went to Home Depot and picked up this 7 oz. jar of Glidden Eggshell Interior for about $3.  I picked out a color chip; it was from Behr, and they asked if it was OK to color match it.

Works well in the airbrush, diluted 50/50 with water.  On the left is Dollar Tree foamboard, stripped, and on the right is EPP.  The photo doesn't do the EPP justice; the grain is emphasize by the direct light.

I've been meaning to paint the leading edges of the EZ-Fly for quite a while... I'll be taking it to the Maker Faire tomorrow, so I took the chance to do it now.  Looks great, I'll update with a picture tomorrow.

tl;dr: Glidden Eggshell sampler works great with airbrush, cheap, can be color matched.

Saturday, October 13, 2012

EastBay RC at the East Bay Maker Faire!

Announcement here, details here.

tl;dr: I'll be helping Chris Anderson with flying the Ardupilot after his talk.  He'll be talking at 11:00, and we'll be demoing from 11:30 to 12:30.

I'm going to summarize what we'll be flying and showing in the next post.

Wednesday, October 10, 2012

What's a "C Clip Support Thrust Collar"?

Turns out it's this thing, which keeps your motor from pushing the shaft out when it's installed in a rear-facing configuration.

Klique provided this picture and notes it should be all the way up against the C clip.

FrSky CPPM Firmware Update

Jani Hirvinen writes:

Status update to all: After several days we gave green light for FrSky for this new custom 27ms software and I am happy to let you all know that software is now publicly available for download.

So if you need to have 27ms and 8 channel output from your PPM capable receivers. Point your browser to FrSky pages and get latest software upload.

For people who did download test files from jDrones (http://www.jdrones.com) website, old files will be now removed and there are only one official software.

FrSky download page for official software is: http://www.frsky-rc.com/download.asp?id=23
Files are under names of:
- CPPM 27ms for D8R-XP
- CPPM 27ms for D4R-II

Background here.
tl;dr: FrSky 8 channel CPPM mode didn't work, this patch fixes.

Tuesday, October 2, 2012

Interesting 4x20A ESC

Here's an interesting ESC from HobbyWing.  I'd like to find somebody that's had some experience with one.  Claims PWM up to 432 Hz.  Not bad for $33?