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Old Aug 26, 2010, 02:15 AM
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Originally Posted by 321 View Post
Another one of the speed controllers went up in smoke. So much for having a spare. These speed controllers are the HK 18Amp SS ones.

Is there something I need to check on the controller before replacing the speed controllers?
Some people are saying it's not much of a problem, and I don't know how I would be able to calculate WHEN it would become a problem but....

Your ESC will SUDDENLY require a serious current when it turns on a motor coil. The wires from the battery to the ESC function electronically as a coil (if you coil-up a wire it works more that way, but a straight wire works as well!). This means that if the current through the wire is now 0A, it cannot be 20A the next moment. It takes a while for the electrons to get going.

So, that's why there is this big capacitor on the ESC: It is closeby, and it will provide the current for the instant that the wire to the battery is not yet adapted to to the new current. Voltage will sag a bit but usually not so much as to be a problem.

Similarly if the ESC suddenly turns OFF a motor, the current will suddenly drop. But that wire is still transporting amps. It takes a while for the battery side of the wire to notice, so it will continue pumping those amps. Again this capacitor will take up the extra electrons. Voltage will spike a bit, but usually not so much that it's a problem.

The capacitor required to solve these problems depends on how much wire you have. So HK designed the ESC with a capacitor that works in the normal case. But if your wires are longer than "normal", that capacitor might not be enough.

Will the ESC blow up spectacularly if the capacitor is the problem? Yes! First the capacitor will be overloaded. Then as the capacitor degenerates especially the voltage spikes will become larger and larger. Once they hit 20V, the power-FETs are outside their safe operating area. They burn spectacularly. And again... once one goes, it will short and take its brother along with it....
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Old Aug 26, 2010, 02:16 AM
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Hey Charl,

Where did you get the pots for your PC board and what K ohms are they?

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Originally Posted by cvandenb View Post
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Old Aug 26, 2010, 02:25 AM
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Originally Posted by spagoziak View Post
Hi again! I'd like to use a switch to control power from the battery. I plan on using 3S lipos, 20C to 30C. The speed controllers are Turnigy Plush 25A. Is this switch an appropriate choice?

http://search.digikey.com/scripts/Dk...ame=67-1934-ND
Not sure where you intend to put the switch (on the battery or on the rail to the board) I hope you want to put the switch on the board

If on the board I would use this

If you want to put a switch on the battery just remember that you could have as much as 50A going though it
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Old Aug 26, 2010, 02:45 AM
That tree again!!!!
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Germantown, MD, US
Joined Sep 2004
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Originally Posted by rewolff View Post
...
The capacitor required to solve these problems depends on how much wire you have. So HK designed the ESC with a capacitor that works in the normal case. But if your wires are longer than "normal", that capacitor might not be enough.
Nice way to explain it. I remember reading some arguments whether to extend wires on the battery side or wires on the motor side. I think the consensus was leaving the battery side wire short and extend the wires on the motor side or adding some caps in the middle of the long wires because of this reason.
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Old Aug 26, 2010, 02:52 AM
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Originally Posted by spagoziak View Post
Hi again! I'd like to use a switch to control power from the battery. I plan on using 3S lipos, 20C to 30C. The speed controllers are Turnigy Plush 25A. Is this switch an appropriate choice?

http://search.digikey.com/scripts/Dk...ame=67-1934-ND
Your four ESCs are capable of pulling 100A total, the 25A contact rating is a bit small. At 1kg (a guess) your quad would hover at around 16A. Close but might work. When you connect a battery it always sparks, this would now happen inside the switch. I expect that this current-inrush is about 1000A. This is so short that all components involved are usually not bothered too much about this.

Sparks usually happen when current is suddenly blocked. So why would my plug on the battery spark when I plug it in? I think that when I first touch the copper contacts, the current rises to that 1000A, but with the small contact, the conducting copper is much too small, and will evaporate, break the connection and spark. There is a visible burnmark on my 120A rated plug!

The contacts in such a switch are much smaller than the 120A plugs that I have. They might get welded together by these currents. Either on the first try or after a few times of use...
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Old Aug 26, 2010, 03:04 AM
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Manchester
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Hi All,

So here is the second video from yesterday i was waiting for.

Here i went to fly inside the woods at my local park. It always feels like a magical place, and being able to fly inside, was just great.

Hope you enjoy it too....

KEEP YOUR SOUND LOW (no music, just prop noise)

KK HexaCopter - 2010-08-25 12pm - Flying in the Woods (3 min 36 sec)
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Old Aug 26, 2010, 03:12 AM
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NL
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Originally Posted by ta2cba View Post
This itg gyro needs a total gyro interface code rewrite.it's I2C.
You could take a look at "baronpilot". It uses I2C to talk to the gyro in a Wii Motion Plus .....
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Old Aug 26, 2010, 03:18 AM
Friend is a 4 letter word...
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Originally Posted by rewolff View Post
You could take a look at "baronpilot". It uses I2C to talk to the gyro in a Wii Motion Plus .....
I would recommend to take a look at TriWiiCopter or Aeroquad instead.....
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Old Aug 26, 2010, 03:20 AM
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NL
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Originally Posted by cvandenb View Post
YYIIPPPEEE - Yet another great flight with my new KK Hex...
Hey Charl,

Have you considered/tried rotating the camera 30 degrees? Then it will point between two props. Humans always focus on the center of an image. and that's exactly where the prop is now. Of course then there would be two props in view...
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Old Aug 26, 2010, 03:28 AM
That tree again!!!!
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Germantown, MD, US
Joined Sep 2004
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Originally Posted by cvandenb View Post
Hi All,

So here is the second video from yesterday i was waiting for.

H...
Niceee. So stable and no shake. I think I'm gonna build a hex
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Old Aug 26, 2010, 04:04 AM
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Manchester
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Originally Posted by patricklupo View Post
Hey Charl,

Where did you get the pots for your PC board and what K ohms are they?
Hey...

Unfortunately i cannot say I bought the board plus all the components as a bundle from Niall. The best would be to PM Niall...
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Old Aug 26, 2010, 04:07 AM
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Norway Haugesund
Joined Jun 2010
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Originally Posted by kapteinkuk View Post
I buy a "TÝrkestativ" from Biltema: http://www.biltema.no/no/Fritid/Hage/Ovrig/Torkestativ/
Hehe Thanx Kapteikuk, then off to biltema we go!

At first I was trying to get my hands on some old tv antenna, I hoped that they did`t trash all the old NRK antennas from the analog times But I was wrong

But "tÝrkestativ" will do the job!
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Old Aug 26, 2010, 04:19 AM
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Originally Posted by rewolff View Post
Hey Charl,

Have you considered/tried rotating the camera 30 degrees? Then it will point between two props. Humans always focus on the center of an image. and that's exactly where the prop is now. Of course then there would be two props in view...
Hey...

Thank you for the suggestion.

I kinda have... but that makes it a bit hard to aim the camera at what you want whilst keeping orientation of the heli...

This is only a temporary mount for the camera... i was just so excited about how great it flies and the video i can get, that i've not completed the final mount.
The final mount will be hung under the frame shooting down and forward, so there should be no part of the heli is view. I have it all ready, i just need a high enough undercarriage, there is a few i have my eye on

Thanks
Charl
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Old Aug 26, 2010, 04:19 AM
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Joined Mar 2010
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420RCpilot,

Could you send me the e-mail please?So that i can start to make my board.
You can also post it here.

Thanks Lowie
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Old Aug 26, 2010, 06:13 AM
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United States, NY, New York
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Originally Posted by rewolff View Post
You could take a look at "baronpilot". It uses I2C to talk to the gyro in a Wii Motion Plus .....
Actually I can talk to ITG3200 with I2C! I have to off those gyros and using them at the moment on another quad project tests Baron pilot uses Wii motion plus which is the cehapest way to build a quad.The celever bit is that he is using wii motion plus as is with wii's I2C interface!I have two wii motion plus snesors but didn't have time to crack it.

Cheers,

BA
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