HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old May 10, 2010, 04:29 PM
Went to mow a meadow
frank48's Avatar
Joined Feb 2007
1,459 Posts
Thanks for the schematic Jurgen, R/C network is high/low pass filter?
Will this be more or less effective for stabilisation than the Kaptn's filter?

Maybe I should just use the gyros on a new board

Frank
frank48 is online now Find More Posts by frank48
Reply With Quote
Sign up now
to remove ads between posts
Old May 10, 2010, 06:09 PM
Friend is a 4 letter word...
JussiH's Avatar
3rd stone from the sun
Joined May 2007
2,677 Posts
[QUOTE=frank48;15056102]I have a walkera ufo#4 and have thought about using the gyro board from it.
It looks to have 5 caps and 2 resistors associated with each gyro, sadly I can't see the values of them.

Think I'll use it as a complete unit, obviously not connecting the accelerometer What do you think?

Has anyone else tried it?

Cheers
Frank[/QUOTE

You could be the first one....try it out - it cant hurt. You can always rip gyros out and use them on a separate board. As far as I remember though the UFO#4 board uses the small version of Gyrostar. So you would need to design boards for the smaller footprint......you could most likely build a 12*12*12 mm gyrocube with those.
JussiH is offline Find More Posts by JussiH
RCG Plus Member
Old May 10, 2010, 06:55 PM
Went to mow a meadow
frank48's Avatar
Joined Feb 2007
1,459 Posts
Thats the way I was thinking... but not having flown a decent quad before I don't feel qualified to make a comparison.

You're right on it about the gyros they are about 8 x 4mm

Cheers
Frank
frank48 is online now Find More Posts by frank48
Reply With Quote
Old May 10, 2010, 10:49 PM
KC9TPL- Get Legit
BloomingtonFPV's Avatar
USA, IN, Bloomington
Joined Aug 2007
841 Posts
ATMega48 and SMD

Just a note for SMD builders that the ATMega48 in at least my 401b gyro is too small to fit in KapteinKUK's current SMD design. The chip in my gyro is 5 mm in width with a .5mm pitch, and the plans call for a 7 mm chip with a .8mm pitch (TQFP, also called the AU form factor).

This is the part listing from the first page of the thread:

IC1: Atmega48/88/168/328 (TQFP) (from some of the gyros)

These seem to be in short supply, but here is one site:

http://www.futurlec.com/Atmel/ATMEGA48-20AUpr.shtml
BloomingtonFPV is offline Find More Posts by BloomingtonFPV
Reply With Quote
Old May 11, 2010, 01:26 AM
Registered User
Australia, VIC, Narre Warren
Joined May 2010
240 Posts
Im just wondering if theres likely to be any reason to go to the bigger chips?

im not sure how close to full the current software is on the 48 chip.

Im also thinking the the newer chips might be a bit easier to find.
Scorpia is offline Find More Posts by Scorpia
Reply With Quote
Old May 11, 2010, 01:28 AM
Jakub J's Avatar
Krakow/POLAND
Joined Dec 2009
1,743 Posts
Quote:
Originally Posted by kapteinkuk View Post
Here is the HexaCopter software

The frame is a quick hack-job made of wooden spatulas and hot glue.
It is going to be replaced with the Sexycopter frame from Jakub (I got for free )....
SEXYcopter is flying to you

Can you write few words about arms configuration?
Should be with one arm on front or two?
Which propellers CW/CCW etc.




Jakub
Jakub J is offline Find More Posts by Jakub J
Site Sponsor
Reply With Quote
Old May 11, 2010, 04:51 AM
Registered User
NL
Joined Nov 2009
304 Posts
Quote:
Originally Posted by Scorpia View Post
Im just wondering if theres likely to be any reason to go to the bigger chips?

i'm not sure how close to full the current software is on the 48 chip.
It's not about flash size, it's about physical size. Having read KapteinKUK's code, I'd say that will fit ten times over in a '48 chip. For maybe just a dollar more, you can get an atmega168 that will provide code space for the far future. I personally decided that the dollar-per-chip was not worth getting into trouble later with code size, so I have a pile of atmega168 chips for all my development projects.

The .8mm pin pitch chips are amateur-solderable (with a bit of care). The .5mm pin pitch chips are not. At least not for 90% of the amateurs.

So personally in my projects I stay away from those .5mm leadless chips if I can.

When necessary I WILL handle them, but only when strictly necessary. Say for my project with the 7260 accelerometer, that can be seen pictured above....

Speaking of which...

Quote:
Think I'll use it as a complete unit, obviously not connecting the accelerometer What do you think?
If you can.... connect the accelerometer outputs to an ADC input on the atmega. Then adding accelerometer support is just a software issue.

If I'm not mistaken, the fact KapteinKUK can hover for over three minutes depends on a bit of luck with the gyros not drifting at all. with an accelerometer, you can measure which side is up, and keep the luck out of it.
rewolff is offline Find More Posts by rewolff
Reply With Quote
Old May 11, 2010, 06:14 AM
Went to mow a meadow
frank48's Avatar
Joined Feb 2007
1,459 Posts
Quote:
Originally Posted by rewolff View Post
<snip>
Speaking of which...


If you can.... connect the accelerometer outputs to an ADC input on the atmega. Then adding accelerometer support is just a software issue.

If I'm not mistaken, the fact KapteinKUK can hover for over three minutes depends on a bit of luck with the gyros not drifting at all. with an accelerometer, you can measure which side is up, and keep the luck out of it.
"Just a software issue" - not a problem for someone who can code

Cheers
Frank
frank48 is online now Find More Posts by frank48
Reply With Quote
Old May 11, 2010, 06:30 AM
Registered User
NL
Joined Nov 2009
304 Posts
Right.

For those that can't there are options.

Suppose you say: Hey KapteinKUK, Roger, if we would connect those to pins xx yy and zz, would the sofware be able to access them?

You'd get an answer....

Then if you'd say a bit later on: Hey, guys I built one extra. It is available to the person who wants to write the software to use the extra sensor! I'm guessing you might elicit some response. :-)
rewolff is offline Find More Posts by rewolff
Reply With Quote
Old May 11, 2010, 06:55 AM
Registered User
Australia, VIC, Narre Warren
Joined May 2010
240 Posts
Quote:
Originally Posted by rewolff View Post
Right.

For those that can't there are options.

Suppose you say: Hey KapteinKUK, Roger, if we would connect those to pins xx yy and zz, would the sofware be able to access them?

You'd get an answer....

Then if you'd say a bit later on: Hey, guys I built one extra. It is available to the person who wants to write the software to use the extra sensor! I'm guessing you might elicit some response. :-)
Along those lines I did have an idea,

From what i believe, the ATMEGA uses an i2c type interface to program it. since this interface is available to the program i was thinking a board could be made that could plug into the ISP port and then be wired to a Wii nunchuck to give the sensors needed. simple upgrade to alot of the boards without alot of redesign.

at this stage it was just an idea, but one that wouldnt be to hard to work out i think.
Scorpia is offline Find More Posts by Scorpia
Reply With Quote
Old May 11, 2010, 07:12 AM
Quad Whisperer
Joined Jul 2008
945 Posts
Quote:
Originally Posted by BloomingtonFPV View Post
Kaptein-
Thanks so much for your updates of the SMD parts. One question:

The HK401B gyros have an ATMega88-10-MU in them, which is great since it is really hard to find ATMegas right now. Does the SMD board use the MU or AU form factor? Can it use either?

I'm assuming that I can use either a 10 or 20 chip since the speed is set by the fuses. Is this correct?

(ok, that was 2 questions )

Once I figure this out I'll re-do my digikey list for people doing the SMD board. It will actually be quite short give that we can re-use a lot from the gyros. Man those things are handy...

It uses the AU form factor. It is easyer to solder. The older "Gyrds" have them.

The speed is set by the fuses, so any speed chip can be used.
kapteinkuk is offline Find More Posts by kapteinkuk
Reply With Quote
Old May 11, 2010, 07:27 AM
Quad Whisperer
Joined Jul 2008
945 Posts
Quote:
Originally Posted by 420RcPilot View Post
As always very impressive - especially last part.....now I just wonder why I didn´t buy 6 motors and ESC´s instead of 4..... I must have it!

Another thing... you mentioned something about gyro scaling affecting quads tendency to backflip. I see this tendecy in my tricopter when pulling up elevator- seems way faster than pushing down elevator? I mitigated it with some tuning of elevator endpoints.

Also I think the .0003 gyro scaling might be too much for tricopter. I am at 10-15 percent gain and very small adjustments yields big changes to gyro response....

But it flies so good compared to my old solution with 4 gyros and CCPM mixing.

Regards

Jussi
I said pitch ADC saturation causes a very fast rotation rate. It happens when the rotation speed exeeds a certain value. Then the rotation speed increases suddenly because the gyro output is limited by the ADC saturation. (negative feedback from the gyro is reduced) You will notice it if it happens I had the endpoints at 140%. It will not be noticable in a normal setup.
It can be fixed by raising the VREF a bit. I will check it out when I have fixed the crashed quad.

I plan to make a special "3D" quad software version. It will gradually reduce the gain toward zero as the stick deflection increases. Will be interresting!

On my TriCopter I have the gains at ca 50%
kapteinkuk is offline Find More Posts by kapteinkuk
Reply With Quote
Old May 11, 2010, 07:30 AM
Registered User
NL
Joined Nov 2009
304 Posts
Quote:
Originally Posted by Scorpia View Post
From what i believe, the ATMEGA uses an i2c type interface to program it. since this interface is available to the program i was thinking a board could be made that could plug into the ISP port and then be wired to a Wii nunchuck to give the sensors needed. simple upgrade to alot of the boards without alot of redesign.
The interface is SPI, not I2C. That, however, doesn't mean that the chip is not able to do I2C on those pins. (I don't know) On the other hand, during development it is highly annoying to have other stuff connected to the programming connector. It's best to try to stay off of that.

My plan was to use an extra ADC input. I've just checked the last schematics I could find, and there are only two ADC inputs left. And these are only available on the SMD version of the chip.

I think an option would be to drop roll and pitch gain into one single pot: in theory they should be about the same?
rewolff is offline Find More Posts by rewolff
Reply With Quote
Old May 11, 2010, 07:41 AM
Quad Whisperer
Joined Jul 2008
945 Posts
Quote:
Originally Posted by pug398 View Post
Guys just a little warning. This weekend my quad went full throttle when the status light lit up and dumbass me was standing too close. Nine stitches later, ego and face bruised, I am ok but be careful. Another reflash and all is fine. Going out to fly now...now where did I put that vest and helmet....
Glad you are OK. The light should only turn on when the throttle is low. Since it was fine after reflash it might have been a bad flash? I can not think of any reasons it should power up with the throttle low.
kapteinkuk is offline Find More Posts by kapteinkuk
Reply With Quote
Old May 11, 2010, 07:46 AM
xxxxxxxxxxxxx
JUERGEN_'s Avatar
Deutschland
Joined Nov 2009
660 Posts
Quote:
Originally Posted by rewolff View Post
. . .
I think an option would be to drop roll and pitch gain into one single pot: in theory they should be about the same?
jes,
has kandidat 100 points!

... simplifies the calibration (setting)


jürgen
JUERGEN_ is offline Find More Posts by JUERGEN_
Last edited by JUERGEN_; May 11, 2010 at 07:54 AM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Quadrotor brushless controller airbotix Multirotor Talk 63 Aug 06, 2010 12:15 PM
Discussion ALPO -Aerobatic Low Parts count Original design. Brian Courtice Foamies (Scratchbuilt) 8 Sep 21, 2009 04:57 AM
Discussion Any tips for my first flight with a low wing plane? Warthog_Fan Fuel Plane Talk 4 Sep 06, 2009 08:53 AM
Help! Need help with Low-cost QuadRotor Hero.sl Coaxial Helicopters 5 Jun 28, 2009 03:26 AM
Question Searching Simple Controller for Free Flight flymax Power Systems 8 Jan 07, 2006 11:07 AM