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Randy's Groups

Randy's Discussions

figuring out the Antenna Tracker

Started this discussion. Last reply by Doug Walmsley on Friday. 41 Replies

ArduCopter-3.2 beta testing

Started this discussion. Last reply by Ray Gamero 9 hours ago. 2918 Replies

ArduCopter-3.1 released!

Started this discussion. Last reply by Bill Isenberger Oct 19. 1530 Replies


Welcome, Randy!

Latest Activity

Oliver Volkmann replied to Randy's discussion AC-3.1 autotune support discussion
"Hi Developers and my fellow users, I would like to share with you my great joy and amazement with the success of an autotune I performed on my SteadiDrone QU4D X. The platform uses 100kv motors and had an all up weight of over 9kg. I was very…"
1 hour ago
Ray Gamero replied to Randy's discussion ArduCopter-3.2 beta testing
"I had to turn my ATC_ACCEL_Y_MAX and ATC_RATE_Y_MAX way down (Both at 4000 I think)  on my trad heli. That really controls the yaw and makes for some great stable shots.  I'm not sure which one of those params made the difference but…"
9 hours ago
Erwin Quilloy replied to Randy's discussion ArduCopter-3.2 beta testing
"thanks for the tip Randy, I will consider it. By the way, is writing on EEPROM permanent? I mean if I filled it up in time, is there a way that I can still modify the contents i have written on it?"
11 hours ago
Zachary Birnbaum replied to Randy's discussion Running SITL on Windows
"Hey everyone, Does anyone know how to get wind to work correctly? Whenever I try to pass in wind from into It initializes to a value of zero. "
16 hours ago
Richard (DK) replied to Randy's discussion ArduCopter-3.2 beta testing
"Hi Randy In AP_NavEKF.cpp the same variable is set to zero twice, first time : second time :; "
19 hours ago
Rana replied to Randy's discussion ArduCopter-3.2 beta testing
"Hi Randy, Sorry, for missing the log files and source, I am attaching it here. "
22 hours ago
Oliver Volkmann replied to Randy's discussion AC-3.1 autotune support discussion
"Hi Brad, I just completed an auto-tune with my quadcopter which uses 100KV motors, 28Inch Props and had an all up weight of over 8kg. Hover thrust was approximately 65%. The Autotune was done in calm wind conditions and was a complete success. I am…"
23 hours ago

Randy commented on Lester Haines's blog post Final LOHAN test flight hits 27,700m
"Congratulations, that's really great!"
23 hours ago
Tetsuo Yamamoto commented on Randy's group Japan ArduCopter Group
"三輪先生、fukuda様 お返事ありがとうございます。 今年は行って見ようと思います。 よろしくお願いします。"

Randy replied to Randy's discussion ArduCopter-3.2 beta testing
"Rana, I don't see your log file attached.  I suspect it will be very similar to the previous two in that the logs suddenly end while the vehicle is in the air which is either a catastrophic software failure or a brown-out.  I think…"
Rana replied to Randy's discussion ArduCopter-3.2 beta testing
"Hi Randy, Very surprising that for the first time even RC5 had a similar crash as that of RC10 and RC12. I am totally surprised and shocked.Two test flights were done today with AC3.2_RC5 (F/W Hash: 515cb7c6710b98ea27d4da85155b35d4b7e3c97c). In one…"
Artem replied to Randy's discussion ArduCopter-3.2 beta testing
"Thx for the reply, will have an opportunity to play with I term coming Saturday. "
Willy Fernandez replied to Randy's discussion ArduCopter-3.2 beta testing
"Randy, we have been very successful in this platform in our aerial activities in the farms. This we owe to the dev team especially to you. Your explanation is very enlightening and reassuring. I can't thank you enough. "

Randy replied to Randy's discussion ArduCopter-3.2 beta testing
"Willy, The heading errors occur when the GPS acceleration (derived from the GPS supplied velocity) doesn't match the actual accelerations from the accelerometers.  I.e. the accelerometers say we're accelerating north but the GPS says…"
Michael replied to Randy's discussion ArduCopter-3.2 beta testing
"Thanks for taking a moment to look at this. Figured it had to be something on my end, but couldn't nail it down. Flies like a dream otherwise. Congratz to yourself and the other devs for the relentless pursuit of perfection. If you ever find…"

Randy replied to Randy's discussion ArduCopter-3.2 beta testing
"Michael, I think the downward pressure of the propellers (possibly only when the vehicle is close to the ground) is causing a large disturbance to the barometer (drops by 4m very quickly).  This leads to the landing-detector thinking the…"

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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