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Old Feb 27, 2014, 11:55 AM
Foam Newbie
Melbourne, FL
Joined Sep 2010
220 Posts
After finally receiving my 939 boards from banggood, I cannot understand how anyone enjoys flying these.

Sure, it hovers fairly stable... but that's about the only thing it is good at. It does a terrible job of leveling itself after a stick input. Giving it full forward, followed by full backwards only results in a limp flip as it plops to the ground.

Stick inputs are soft, even without expo on my Devo 7e. It feels like you are constantly over-correcting. After flying wltoys v202 and v252 series FCs, the 939 board is a joke.

I wouldn't even give away a 939-powered quad to a friend, for fear that it would misrepresent the hobby! They would surely fly it a few times, get frustrated and assume all quadcopters are not fun.
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Old Feb 27, 2014, 05:59 PM
RC beginner
New York
Joined Oct 2008
5,633 Posts
lol. spoken by a man who apparently does not know what accelerometers are or what they do. theres no doubt these help beginners maintain stable attitude but experienced flyers often disable this for more responsive "sport" flying. not all models allow both modes but some do, walkera being one example. a little time spent on some of the megathreads here tells the story.

i do find it odd that none of the flysky/9x compatible models have accelerometers.
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Old Feb 27, 2014, 10:29 PM
Foam Newbie
Melbourne, FL
Joined Sep 2010
220 Posts
I am familiar with accelerometers or flying "acro". I'm just late to the quadcopter scene and expected more from the 939 fc after flying hubsan, blade nano and wltoys powered quads.

Dave, please don't take it as a criticism of your work here. I found your building techniques to be very valuable, enjoyed construction and the goal of keeping it cheap. Thank you for your contributions.
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Old Feb 28, 2014, 11:05 AM
RC beginner
New York
Joined Oct 2008
5,633 Posts
thanks and please dont think im criticizing your opinion. many others who started with accel quads share it. if you were forced to learn the "frisky" models first like me then the super stable ones do seem very impressive at first but there are many things you can do with "sport" mode that cant be done in "stable" mode. it just takes some getting used to. no matter what your input was welcome because it brought up a very important subject.

as mentioned too bad there are no flysky compatible units available with accel for those days when i dont want to wear myself out with the balancing act but just like to float around.
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Old Feb 28, 2014, 01:07 PM
Foam Newbie
Melbourne, FL
Joined Sep 2010
220 Posts
I fully agree, love my 9x but had to give in and pick up a devo to fly these newer "6axis" quads.

What are your thoughts on phracturedblue's work on a universal module? Given your impressive work on the deadbug rx, do you think it's feasible to implement his module on a 9x?
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Old Mar 31, 2014, 08:00 PM
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Joined Mar 2014
5 Posts
Hi there,

Wow, I like this. I think I want to build one. May I ask a few questions:

From my partial reading of this thread, I gather that the 939 boards have gyros, but not accelerometers. Thus, the quad will not stop if you let go of the controls. Am I right? Also, is the stabilization comarable to other gyro based stabilization systems? (e.g. the 1sq TAGS from Heli-Max)

Second question: Will this work with the rtf transmitter that comes with the helimax 1sq?

Now I'll just summarize what I understand you to be saying that I need to do to build one of these:

Frame: make it out of bamboo skewers, etc.
Motors: any of the ones you listed in your original post.
Controller: http://www.banggood.com/Wholesale-Wl...5-p-49468.html
Battery: stock v939 used 300mah lipo (I assume I can find it on banggood.)
Anything else?

One more question? What would be the cheapest way for me to make a transmitter if I don't have anything but experience with soldering and microcontrollers?

Thanks in advance and pardon me if the answers are obvious. I did search quite a bit.
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Last edited by TinyTree; Apr 01, 2014 at 07:49 AM. Reason: More Questions
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Old Apr 01, 2014, 04:58 PM
RC beginner
New York
Joined Oct 2008
5,633 Posts
hey... welcome to the MONKEY house rc groups. CHEAPEST radio would be to use diy plans from these guys:

http://www.rcgroups.com/forums/showthread.php?t=1817699
http://www.rcgroups.com/forums/showthread.php?t=1921870

EASIEST path is to pick up a v929/v939 radio from banggood. hard to beat $12-$14 for ready-to-go solution.

i have no experience with heli-max but your shopping list looks pretty complete. maybe a pack of ebay 2 pin 1.27mm connectors for the motors.
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Old Apr 01, 2014, 05:04 PM
RC beginner
New York
Joined Oct 2008
5,633 Posts
Quote:
Originally Posted by Jefte View Post
What are your thoughts on phracturedblue's work on a universal module? Given your impressive work on the deadbug rx, do you think it's feasible to implement his module on a 9x?
phracturedblue is the father of all these flysky projects but im not so much into the deviation part. seems best for those who already have one of their heli transmitters but personally im a 9x guy. for "universal" ideas probably best are midelics threads in diy electronics forum along with some 9x stuff here:

http://www.rcgroups.com/forums/showthread.php?t=1631369
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Old Apr 01, 2014, 06:14 PM
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Joined Mar 2014
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Quote:
Originally Posted by dave1993 View Post
hey... welcome to the MONKEY house rc groups. CHEAPEST radio would be to use diy plans from these guys:

http://www.rcgroups.com/forums/showthread.php?t=1817699
http://www.rcgroups.com/forums/showthread.php?t=1921870

EASIEST path is to pick up a v929/v939 radio from banggood. hard to beat $12-$14 for ready-to-go solution.

i have no experience with heli-max but your shopping list looks pretty complete. maybe a pack of ebay 2 pin 1.27mm connectors for the motors.
Wow, I didn't realize that there existed such cheap off-the-shelf transmitters. This is quite tempting...

On the other hand, I wanted to build my own helicopter primarily because I wanted to add my own stabilizer code that used accelerometers so that the quadcopter would stop when I let go of the controls. What would you recommend for that. What about this thread of yours?:
http://www.rcgroups.com/forums/showthread.php?t=1798913

Thank you so much for your help.

EDIT: After looking more carefully at the links you referred me to regarding building my own transmitter, I realized that you already mostly answered my last question. Sorry about that.
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Last edited by TinyTree; Apr 01, 2014 at 06:31 PM.
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Old Apr 02, 2014, 06:47 PM
RC beginner
New York
Joined Oct 2008
5,633 Posts
checking those links out i see they bumped price up from $12 last summer to $17 now. still not a bad deal considering what you get. midelic owes me one for losing a bet. i hope he pays off before they hit $20 and at which point i think he could no longer afford it. lol.
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Old Apr 02, 2014, 07:41 PM
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Joined Apr 2012
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There are 2 guys now( excluding me ) I know of..using my integrated mwii code succesfully.
I'm surprised you still using attiny.......when the mwii flysky integrated working well.I have one quad and one tri using it ..without problem......when you really honestly wish to test again,... call me...I can help you removing your doubts.
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Old Apr 03, 2014, 06:22 PM
RC beginner
New York
Joined Oct 2008
5,633 Posts
Quote:
Originally Posted by midelic View Post
There are 2 guys now( excluding me ) I know of..using my integrated mwii code succesfully.
you know imaginary friends dont count...right?

actually i do think its possible there was some wiring problem or other small detail overlooked in my setup and possibly the other guys who tried and failed too. so i will build another prototype from scratch just using your instructions. soon but not right way due to other activities.

what i cant understand is why, out of thousands of readers of those threads, at least a few dozen diyers havent come out to show off their success. its a mystery because, like with the diy frsky rx&tx, these projects are among the most revolutionary developments since sliced bread. where is everybody hiding?
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Old Apr 03, 2014, 07:02 PM
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Yes the problem ,the other 2 guys contacted me by email..and didn't post here.

I had the same impression,,that they'll jump on Frsky Tx/Rx or the nunchuck...but nothing.....I think there was too many developments in the last 2-3 years in this hobby...and people cannot keep up ,they got tired.You remember how was not more than 2 year ago...and how things advanced.
Yes too many new things, new toys....
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Old Apr 03, 2014, 10:01 PM
Quadrocopter Builder
United States
Joined Apr 2014
31 Posts
That is pretty cool!
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Old Apr 03, 2014, 11:53 PM
Registered User
Austria
Joined Jan 2004
6,064 Posts
Quote:
Originally Posted by dave1993 View Post
you know imaginary friends dont count...right?

actually i do think its possible there was some wiring problem or other small detail overlooked in my setup and possibly the other guys who tried and failed too. so i will build another prototype from scratch just using your instructions. soon but not right way due to other activities.

what i cant understand is why, out of thousands of readers of those threads, at least a few dozen diyers havent come out to show off their success. its a mystery because, like with the diy frsky rx&tx, these projects are among the most revolutionary developments since sliced bread. where is everybody hiding?
I have the impression that there are not so many reader on the DIY section, and there are even less people doing/following the DIY projects here

So, I'm not surprise if only few people report success on following the m projects ... that as far as I was able to verify they did work normally

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