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Old Oct 27, 2012, 01:05 PM
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Originally Posted by GSD View Post
+100.... this is the truth!
Have you done any investigations? A regulator doesn't suck current to lower a too high voltage on it's output, but it supplies current to maintain the voltage over the load connected to it's output.
Just did a test with one of those small 5V regulators that was piggybacked on each other in an ESC. Even connecting the input and output together, thereby rising the output voltage to 12V, had no bad effect Current flowing into the output was 1.6mA. Connecting this 5.09V regulator in parallel with another BEC at 5.23V represented no problem either. "Sink current" was 0.7mA in this case. BTW, the second one was a switch mode BEC, but that's not recommended.
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Old Oct 27, 2012, 01:12 PM
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Croatia, Osijek-Baranja County, Valpovo
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Originally Posted by GSD View Post
Today i did some flying to my Sk450 KK2.0 with very strong air! I noticed that Self Level was a very dangerous thing!!! If engaged.. the wind took my quad far away having difficulty to control it!!! Without SL it was much easier to fly stable and controllable with such a strong wind... Also.. one stupid question.. i see you guys in your videos flying far away enough so its very difficult to 'understand' its orientation... how i can overcome this? I know SK450 is small.. but almost every quad if goes some meters away (even colored, or with signs etc) its difficult to understand its orientation.. I was impressed also by Upup with Dex Mini crash test.. this little thing to fly in such speeds?...

Have higher rates on tx for self level if response is to low,
other method is increase stick scaling and have dual rates on tx if
100% is not enough for self level.

Self level is good thing ( if it works) help on wind to,
when you lose orientation ( many do) self level is difference between crash and see-check-try-return .

Orange ping pong balls are helpful for orientation,
put as many as you can on tail.
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Old Oct 27, 2012, 01:38 PM
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Originally Posted by GSD View Post
... Also.. one stupid question.. i see you guys in your videos flying far away enough so its very difficult to 'understand' its orientation... how i can overcome this? I know SK450 is small.. but almost every quad if goes some meters away (even colored, or with signs etc) its difficult to understand its orientation...

Be aware that cameras can lie. Cameras with a very wide FOV will make it look like the quad is farther away than it really is.

LEDs in different colors on every side will help with orientation.
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Old Oct 27, 2012, 01:45 PM
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Originally Posted by flarssen View Post
Have you done any investigations? A regulator doesn't suck current to lower a too high voltage on it's output, but it supplies current to maintain the voltage over the load connected to it's output.
Just did a test with one of those small 5V regulators that was piggybacked on each other in an ESC. Even connecting the input and output together, thereby rising the output voltage to 12V, had no bad effect Current flowing into the output was 1.6mA. Connecting this 5.09V regulator in parallel with another BEC at 5.23V represented no problem either. "Sink current" was 0.7mA in this case. BTW, the second one was a switch mode BEC, but that's not recommended.
I hate to say it but I NEVER cut or pull any power wires from my ESCs.I use primarily Plush 30s and I have two sets of Plush 12s. All work just fine and I have never even felt a warm one. My largest airplane flies with 4 cell 4000 Mah packs and even those aren't even warm to the touch after a 15 minute flight.

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Old Oct 27, 2012, 02:07 PM
Live to fly... fly to Live!
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Sorry.. Wrong post..
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Old Oct 27, 2012, 02:10 PM
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Originally Posted by brontide View Post
The acc mod to 1.2 makes a world of difference in wind, I have experienced with both in wind and the stock was just as you describe.
You mean this version with the "death flip"? I didn't understand what exactly is happening, but as newbie very afraid to test!!!
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Old Oct 27, 2012, 02:15 PM
GSD
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Quote:
Originally Posted by flarssen View Post
Have you done any investigations? A regulator doesn't suck current to lower a too high voltage on it's output, but it supplies current to maintain the voltage over the load connected to it's output.
Just did a test with one of those small 5V regulators that was piggybacked on each other in an ESC. Even connecting the input and output together, thereby rising the output voltage to 12V, had no bad effect Current flowing into the output was 1.6mA. Connecting this 5.09V regulator in parallel with another BEC at 5.23V represented no problem either. "Sink current" was 0.7mA in this case. BTW, the second one was a switch mode BEC, but that's not recommended.
I was talking about the normal behavior that from a higher voltage source always flows current to a lower one connected in parallel trying to balance... The same as in theory of liquids.. But if you measured so low currents it's acceptable too...
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Old Oct 27, 2012, 02:24 PM
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Originally Posted by srepfler View Post
Have higher rates on tx for self level if response is to low,
other method is increase stick scaling and have dual rates on tx if
100% is not enough for self level.

Self level is good thing ( if it works) help on wind to,
when you lose orientation ( many do) self level is difference between crash and see-check-try-return .

Orange ping pong balls are helpful for orientation,
put as many as you can on tail.
I'm still learning. Maybe three dozen +/- batteries through a little v929 and maybe 20 on my tri. This after returning to R/C after a 12 year hiatus. I flew gliders before that.

I had a bad crash in wind when I had SL accidentally turned on. Was wondering why I had (almost) no control. However, I hadn't got around to setting it up yet. Certainly it had very little authority with the stock settings.

My experience with orientation is that the more you fly the better you get at "knowing" (maybe following) which way it's going. I still get it wrong from time to time though.

I need to build a new frame after another bad crash. Going to try a T-copter layout to see if that's any more distinctive in the air.

Also hoping to get SL tuned properly (as I think it would have saved a few prangs if it works as a "bail-out". Then more stick time to try to get Forward Flight coordinated turns sorted. That's where I'm having problems right now. Not sure if I was under or over rotating, but would end up sliding sideways into the ground. Suspect that some height dampening trim might help here too.

It's been a big help following everyone else's learnings and experiences here.

cheers,
Andrew
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Old Oct 27, 2012, 03:04 PM
<Marty>
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how exactly does the height dampening work anyway? i have read thru the manual and it doesn't explain how to set it up or use it...

also could not find which way the usbasp plugs into the board...as it has 6 pins it could be plugged in eather direction...
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Old Oct 27, 2012, 03:22 PM
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Originally Posted by magic_marty View Post
also could not find which way the usbasp plugs into the board...as it has 6 pins it could be plugged in eather direction...
if you put the right direction you'll get the LCD light up.

wrong direction = nothing happen.
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Old Oct 27, 2012, 04:17 PM
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Originally Posted by magic_marty View Post
Where could i get Mikes firmware? i have a older KK board i might give it a try on...

could anybody tell me how to tell which way the plug goes for updating the firmware? i looked in the manual and it doesn't mention it...if its hooked up backwards by accident will it damage the board?

thanks a bunch...
Pin 1 of the 6-pin connector goes to the outside edge of the board (near the mounting hole). Reversing it won't damage anything. I've reversed mine many times...
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Old Oct 27, 2012, 04:51 PM
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Flashed New firmware

Well I now have flashed both of my HH2 boards with Shanes modded firmware. I see a big difference but now I am going to have to go back out to the tall grass and do the P&I adjustments again. I am thinking I will also put a little expo in to soften my touch. It certainly is more responsive.Guess I will have to wait for this hurricane to blow thru first.

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Old Oct 27, 2012, 05:23 PM
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Originally Posted by flarssen View Post
Have you done any investigations? A regulator doesn't suck current to lower a too high voltage on it's output, but it supplies current to maintain the voltage over the load connected to it's output.
Just did a test with one of those small 5V regulators that was piggybacked on each other in an ESC. Even connecting the input and output together, thereby rising the output voltage to 12V, had no bad effect Current flowing into the output was 1.6mA. Connecting this 5.09V regulator in parallel with another BEC at 5.23V represented no problem either. "Sink current" was 0.7mA in this case. BTW, the second one was a switch mode BEC, but that's not recommended.
I just did an experiment to check. You are correct in that the regulators don't sink current. So the problem is simply that they don't *share* current.

I opened up a 25A SS-series ESC that has the laughable BEC current rating of 3A. I measured each of the two parallel regulators by disconnecting one.
Reg 1 = 4.88V, Reg 2 = 4.99V. Together the output is 4.99V.
Incidentally for the 34mA load I was using, 65mA was required at the input, showing the rather poor efficiency of the linear regulators.

Ok so the problem with SS series regs and other badly-designed ones is that - as they don't use current-sharing resistors only ONE reg is actually on at any time. This explains why I could feel one heating up, then the other, as each went into thermal shutdown or overcurrent limit, then the other.

The regulators used in the SS the device is an LF50A in the D-PAK package. The datasheet rates them as "up to 500mA" but they are internally limited to 1A.
I note that it claims a worst-case 500mA load regulation of 25mV, which means that in my example, even at 500mA the 4.99V reg would not sag enough to enable the lower 4.88V one.

With a fully-charged 3S LiPo at 12.6V, 500mA would dissipate a massive 3.8 Watts. The D-PAK has a junction-to-ambient rating of 100 degrees per Watt but in the SS, they are soldered to a tiny pad to aid dissipation. It's hard to guesstimate the thermal resistance but let's be generous and say it's twice as good and so 50 degrees * 3.8W = 190 degrees C.
At 100mA the disspation is 760mW and the heat rise about 38 dgrees C. That sounds about right as the things warm up extremely quickly.

For a laugh, let's work out what would happen if some one believed that 3A rating printed on the HobbyKing SS-Series ESC wrapper...
Let's also be generous and say that the higher regulator sags to the point where both regulators are supplying power.
At 3A, 22.8W is dissipated across the pair of ESCs. 11.4W each. This would cause each to rise to... oh look 570C... and they desolder themselves off the board lol. Of course they would shut down before that but you can see that the rating is completely fraudulent.

So to summarise, with these kind of linear regulators, they won't indeed fight each other when connected in parallel, but they are unlikely to help each other either, due to the fact that...

1. They have excellent load regulation and so won't sag.
2. There are no current-sharing resistors to *induce sag* and...
3. A BEC power lead will not result in significant sag.
24AWG wire will drop 5mV per foot at 100mA,
26AWG wire will drop 8mV per foot at 100mA,
28AWG wire will drop 13mV per foot at 100mA.
So basically, ESCs with linear regulators suck and are completely unsuitable for parallel use as they are unlikely to share current unless designed to do so. However I can no longer see why there is any problem connecting them in parallel as long as you realise that quite possibly only one, 500mA regulator is powering your *whole system*. If you're good with that, no problems.
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Old Oct 27, 2012, 05:41 PM
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Quote:
Originally Posted by GSD View Post
one stupid question.. i see you guys in your videos flying far away enough so its very difficult to 'understand' its orientation... how i can overcome this? I know SK450 is small.. but almost every quad if goes some meters away (even colored, or with signs etc) its difficult to understand its orientation..
overtime with practice and more practice! the coronation well come..only took me a full summer.
read post http://www.rcgroups.com/forums/showp...postcount=5795


Quote:
Originally Posted by magic_marty View Post

could anybody tell me how to tell which way the plug goes for updating the firmware? i looked in the manual and it doesn't mention it...if its hooked up backwards by accident will it damage the board?
thanks a bunch...
no its not like the other KK's if you plug in wrong the LCD well not light up...


Quote:
Originally Posted by Banjo5 View Post
I had a bad crash in wind when I had SL accidentally turned on. Was wondering why I had (almost) no control. However, I hadn't got around to setting it up yet. Certainly it had very little authority with the stock settings.

My experience with orientation is that the more you fly the better you get at "knowing" (maybe following) which way it's going. I still get it wrong from time to time though.

I need to build a new frame after another bad crash. Going to try a T-copter layout to see if that's any more distinctive in the air.

Also hoping to get SL tuned properly (as I think it would have saved a few prangs if it works as a "bail-out". Then more stick time to try to get Forward Flight coordinated turns sorted. That's where I'm having problems right now. Not sure if I was under or over rotating, but would end up sliding sideways into the ground. Suspect that some height dampening trim might help here too.

It's been a big help following everyone else's learnings and experiences here.

cheers,
Andrew
i assume you calibrated the sensors and had the board/Quad on a level (as possible)surface? Yes i agree it just takes practice. As for while in AL the higher the numbers on the P and I in the (Autolevel menu) the more control you have. I have mine at 20 and 20 on the P and I. There are many ways to dumb down your yaw if you over shooting..either turn the scaling down or the EPA or D/Rs in your TX. once you find your sweet spot it we be...well sweet...

Quote:
Originally Posted by magic_marty View Post
how exactly does the height dampening work anyway? i have read thru the manual and it doesn't explain how to set it up or use it...

also could not find which way the usbasp plugs into the board...as it has 6 pins it could be plugged in eather direction...
Nice that you have read the manual and all,
As for Height dampening read
http://www.rcgroups.com/forums/showp...postcount=5795

it was only posted last night, last page!!
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Old Oct 27, 2012, 05:50 PM
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Originally Posted by kapteinkuk View Post
Some thoughts on C converting:

I have been wrestling the ImageCraft C compiler for a few days now.

I know I said to use GCC, but after using many hours to get it to compile the most basic example code (GCC is very picky regarding compound expressions and requires a million parentheses, and also trying to get the list file was mostly unsuccessful) I decided to google "best C compiler for AVR". What a mistake, haha. After reading 10000000 different opinions for another X hours, I decided to try imageCraft.

Things I learned:

1: Each of the source files have their own scope, and requires endless* layers of header files to communicate. I know object oriented programming and see advantages with only exposing input and output variables, but it feels like overkill in this case.

2: Complicating stuff: Setting a single bit in I/O is done by "PORTA |= 1<<n" I know that a good C compiler recognizes this and uses the "SBI PORTA, n" instead of literally translating it to "in t, PORTA", "ori t, 2^n" and "out PORTA, t".

3: It would not let me write macros that sets single bits without nesting macros like the Russian Matryoshka dolls*. ASM does that with a single macro.

4: There where no delay function. I ended up writing my own in C and trying to calibrate it with a stop-watch like a noob. I prefer to count cycles.

5: I saw a "NOP" in the list file

6: Writing inline assembly is a pain. Also the usr manual says I can not reserve spesific registers for my own use and I can only access the low byte of a C variable...

On a positive note, the text editor is really good. Much better than Atmel's stone-age editor. Does anybody know of a similar editor for AVR? I do not dare to google it

Until now I had only written the hardware initialization in C and already reached 5 files...

...so I think I will descend into the dark again and improve the resolution of my math library and have another go at the damn AHRS.





*: May be an exaggeration.
I have been shocked when I read you did decide to abandon ASM for go to C

C is excellent for computer, but not for micro devices, which timing is extremely important

I had some experience with atmel chips and avr studio ... but in my opinion once you get familiar with asm, coding in asm is faster and more efficient

If all what you need is to fix your math library ... just make then in C and compile it ... then look at the asm code produced and you have a valid working template/reference

Tchuss

E_lm_70
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