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Randy's Groups

Randy's Discussions

figuring out the Antenna Tracker

Started this discussion. Last reply by Doug Walmsley 2 hours ago. 41 Replies

ArduCopter-3.2 beta testing

Started this discussion. Last reply by Ravi 1 hour ago. 2830 Replies

ArduCopter-3.1 released!

Started this discussion. Last reply by Bill Isenberger on Sunday. 1530 Replies


Welcome, Randy!

Latest Activity

Ravi replied to Randy's discussion ArduCopter-3.2 beta testing
"@manu, the solar activity was very high on oct 20 and oct 21. The K-index was 5. so it is quite possible that my GPS loss was becasue of solar activity. what i am doing is that i will try using the new ublox M8N GPS which is supposed to lock to 19…"
1 hour ago
Doug Walmsley replied to Randy's discussion figuring out the Antenna Tracker
"First I want to explain that I built a Antenna Tracker using the PT785-S system from Servo City and installed a Pixhawk, Lea-6H 3DR GPS/Compass, and two 3DR 900Mhz radios.The first Radio is in Telem1 port and works fine when connecting Mission…"
2 hours ago
Brad replied to Randy's discussion AC-3.1 autotune support discussion
"I tried again this morning after disabling gimbal stabilization so the servos won't move.  The result was similar (worse, actually).  One last thought.  I am not starting autotune via sw7/8 but I think I have arranged via a…"
6 hours ago
Artur replied to Randy's discussion ArduCopter-3.2 beta testing
"rc-13 works very well. I tested modes: stabilize, alt_hold, loiter, pos_hold, auto. Good job!!!"
7 hours ago
Doug Walmsley replied to Randy's discussion figuring out the Antenna Tracker
"HI All!  I'm in the process of tuning my PT785-S Pan & Tilt System with a LCOM 900Mhz and a 5.8Ghz BiQuad antennas.  I've posted pictures in my photo album if your interested.   @iskess, I know mmy reply is late as…"
12 hours ago
Doug Walmsley replied to Randy's discussion ArduCopter-3.2 beta testing
"Great readings!  However, What I don't see is where the battery is located, nor the PDB or ESC for that matter.  Like folks mentioned before, the issue with GPS signal loss may have nothing to do with your electronic interference but…"
12 hours ago
Johnex replied to Randy's discussion ArduCopter-3.2 beta testing
"You need to click the "Help" tab in Mission Planner and click "Check for BETA Updates" at the bottom of that page. PosHold is missing from the "stable" mission planner but is fixed in the beta."
13 hours ago
Gustav Kuhn replied to Randy's discussion ArduCopter-3.2 beta testing
"Grounded to WHAT ? This topic surfaces, gets beaten to death, and surfaces, again, a few months later. If it is RF(radio frequency) interference, it will ONLY affect either the RX, or the GPS, or both. If you effectively shield those from the…"
13 hours ago
Jon Currier replied to Randy's discussion ArduCopter-3.2 beta testing
"The copper foil, or any shielding needs to be grounded to work"
14 hours ago
Manu B replied to Randy's discussion ArduCopter-3.2 beta testing
"Regarding GPS and compass, we tried something that was not supposed to be changed later, but well... this is working fine. Not recommended at all, however we have no issue at all when flying. Yes, we have the ublox gps/compass sitting close to…"
15 hours ago
Richard Kennedy replied to Randy's discussion ArduCopter-3.2 beta testing
"I wish I knew what they used. I bought some copper foil but it seemed to have no effect.  "
15 hours ago
Phanivyas replied to Randy's discussion ArduCopter-3.2 beta testing
"Today I had 2 flights with 3.2 rc12. Stabilize, Alt Hold, Position Hold, Loiter works great. I have done a complete flight in Position Hold mode. The only problem was when I had switched "Land" mode, the copter descended nicely but after…"
15 hours ago
Manu B replied to Randy's discussion ArduCopter-3.2 beta testing
"Great, I will test this during the weekend. I'd like to test PosHold, but MP does't ask list it. By changing the parameter to 16, should it work even if MP doesn't seem to display this flightmode? I will also run modified parachute…"
16 hours ago
Ravi replied to Randy's discussion ArduCopter-3.2 beta testing
"thanx fellow drone flyers for so much of support. i really admire this community. i ran the compassmot. the value was less than 30%. I will now move the GPS 5cm up from the current location and further away form the pixhawk and PDB. i have a 500mW…"
16 hours ago
Martin replied to Randy's discussion ArduCopter-3.2 beta testing
"Randy, I too had issues with occasional fly-aways with Pixhawk (and EKF On) that never happened before with AMP 2.6, but I think I may be on to the root cause now. I thought it was GPS at first, but it seems maybe not now... With the APM 2.6 I never…"
17 hours ago
Nick replied to Randy's discussion AC-3.1 autotune support discussion
" Here's a test I did very recently. From what i've read on the wiki, this is well within the limits (red bars). Ill put stab_P on a pot and play with it this weekend and see what happens."
18 hours ago

Profile Information

About Me:
Lead developer of ArduCopter. I coordinate releases, provide support for users having trouble with their copters, add new features (most often based on ideas and suggestions from the community). I also help others get their code integrated into ArduCopter.

You can find numerous video tutorials from me here:
Please tell us a bit about your UAV interest
Interested in quads and helis mostly. I got my start in this field by reading the electronics tutorials from Sparkfun and from watching the success of Jack Crossfire's vicacopter. I've learned an enormous amount from the combined wisdom of the people on the DIYDrones forums and members of the core dev team including Jason Short, Tridge, Doug Weibel, Leonard and many more.
Karuizawa, Japan

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Randy's Blog

Red Balloon Finder

Posted on June 17, 2014 at 5:04am 30 Comments

As many probably know, this year's Sparkfun Autonomous Vehicle Competition (AVC) is similar to last year's except that a new challenge has…


GPS Glitch detection in AC3.1

Posted on December 14, 2013 at 6:42am 32 Comments

AC3.1 is going out very soon and includes a new safety feature called GPS glitch detection.  There's a wiki page about it but I'd like to highlight how it works because it's near the top of the list of safety issues.  The method…


Dropping a Rover from Hexacopter - Part III

Posted on August 22, 2013 at 7:40pm 32 Comments

As a follow-up to the rover drops #1 and #2 I spent a day with Assistant Professor Nagatani-san of…


UAVs for measuring radiation levels in Japan

Posted on April 11, 2013 at 6:38pm 11 Comments

Two years after the March 11th tsunami in Japan that triggered the Nuclear disaster at the Fukushima power plant, there are still just over 300 thousand people who have not been able to return to their homes due to…


Dropping a Rover from Hexacopter - Part II

Posted on March 15, 2013 at 12:32am 14 Comments

As a follow up to an indoor test we did a about a month ago (blog post here), Assistant Professor Nagatani-san of Tohoku University, Izu-san of…


Comment Wall (24 comments)

At 8:44am on January 5, 2011, Jack said…


I have been working on my own Quad with the NG code and have setup the Sonar and have it working very well . I have an indoor version with sonar and IR sensors and would like to know were the IR sensors are conected, what pins. I see you were working on implementing this so If you could help with basic setup I can try my hand at testing. Thanks for your work on the Sonar and good luck on the obstical avoidence.


At 5:47am on January 30, 2011, Kári Davíðsson said…

Thanks Randy. 

I do not have write access to the svn repository.

So I will send you the changed AP_ADC lib probably later today.

I am not sure if a circular buffer is needed. The beauty of a 1st order IIR filter is that we only need one "old" sample and if a second order is needed only two old samples. But I will look a little better into the filter selection before committing anything to you.

At 5:45am on August 24, 2011, Jiro Hattori said…

Hi Randy

 One of the way to introduce technology of arduino as IMU is that something like what you have done. Most of the Japanese model flyer love to fly traditional helicopter. 

 Another approach may be exhibit something very unique at MAKE fair at Tokyo Institute of Technology.  There will be many open source hardware and software freaks as well.

At 9:10pm on March 7, 2012, Ravi said…

hi randy, i had been following your forum for align450. i just got my APM2 purple. i loaded the ardu heli firmware. everythings looks to be ok on mission planner. but there is no PWM on servo out pins. i armed the APM2 and does gets armed. the radio callibration bars move proportionately. evrything seems to be OK. but in 'status' there is no PWM on channel out pins. it shows '0' PWM on all out channels. can uou please suggets what might be the reason. the APM2 works fine with arduplane and arduquad firmware. ravi

At 5:53am on March 16, 2012,


I had a different problem with my APM2 that I was able to solve by following the procedure found in the wiki with a search for APM board problems.  My board would not connect to the planner and it works now.

Good luck


At 2:18pm on May 15, 2012, wilson javier madrid sossa said…

hello hello hug.
I can help with anything, I did several plannings flight with tri and firmware 2.0.49 and flew very well.
I did a quad and install 2.5.4 program a waypoint flight and the team took off like crazy.WP PIDs are by default and does not really move as you do. can you give me some information.

I appreciate your help

At 4:41pm on May 16, 2012, wilson javier madrid sossa said…

Please can you help me. I was flying my quadcopter and hold position when you turn the team went to ground. these are the last two log. I appreciateprompt help.


At 3:54pm on September 29, 2012, Marooned said…

Hi Randy

After your changes to Optical Flow I'm having troubles with compiling the sources:

ArduCopter.cpp: In function 'void init_ardupilot()':
ArduCopter.pde:-1: error: 'SPI3' was not declared in this scope
ArduCopter.pde:-1: error: 'SPI3_SPEED_2MHZ' was not declared in this scope

I have spi3.h file include in ArduCopter.pde but somehow it's not working that way. I did fetch&rebase with original repo.

At 3:12pm on September 30, 2012, Marooned said…

Sorry for troubles. It's working now. Looks like Arduino IDE had some hiccup.

I should probably move to some better IDE as I'm using Arduino only for compiling/uploading and all files are edited in my fav editor and I have to restart Arduino every time I change something as it doesn't follow outside files changes.

Anyway, sorry for bothering you.

At 6:30pm on December 1, 2012,
William Premerlani

Hi Randy,

Regarding a question that Shyam asked about gimbal lock when he was trying to use APM to stabilize a camera, he and I finally solved the issue. Here is a link.

No one on diydrones was able to help Shyam, he finally contacted me directly.

Best regards,

Bill Premerlani

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