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Hi skimask,
Maybe I am always wrong...
Maybe my english isnt good enough...
But I think, it is not shame not knowing it is shame not learning ...
If you wont help me ,dont reply my words please...
When I read your words,I feel like humiliated
Thats all...
Last edited by burak450; - 4th October 2008 at 00:25.
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No one is trying to humiliate you. In fact, it looks to me like skimask is giving you a lot of help. Complete code is not help.Originally Posted by burak450
Let me ask you to do something. Imagine how hard it is to help someone long distance like this? Sure the code can be posted and looked at easy enough, but what about the hardware that wee can not see or test.
Now think about the kind of person that will tale the time to work through the kind of problems that we see on this forum.
Now think about how you might make the person that is trying to help feel with your last post.
There are many many people here that could help, but only a few that take the time. No wonder there are so few willing to help.
That all said.
Try a battery pack on your servos. If it is noise from the power supply like Nick said, that will stop it.
And like skimask ask, show a picture of you power supply. As you are finding out, power supplies can be tricky.
Dave
Always wear safety glasses while programming.
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Whoa, hey, back up a bit here... Your English is a lot better than my __________ (insert any language other than English here) and completely understandable (if not a bit grammatically incorrect, but that's ok).
What I'm saying is that you aren't listening very well. We believe the core of the problem to be power issues and you keep talking everything but power issues (i.e. code problems, etc) thinking that your power is infallible, when judging from the problems described, it looks like a power issue...for the last 60-ish posts. How long did it take you to finally add a capacitor?
Think what you want, but in the end, I'd bet on a power supply problem...
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It's not about not listening,its about not understanding..
Sometimes i dont get what all people said because i dont know too much about power issue...
I appreciated what you did for me up to now..But say your word please more polite...
I swap the servos and tried first program(single servo program) which worked perfect...
But stiill remained vibration on up_down servo.I think thats interesting..
There is no vibration or oscillation whatever you called, on left-right servo...
Is this servo broken?
I have to tell you another things...
I connected 9v battery same problems remained...
I tried two parallel 7805 and it makes servo slow because when I tried a single 7805 ,it worked fast...
Thats gonna be a weird question but i want to ask:
Second servo wanna have more current? Or is it broken?
I cant explain why it vibrates...
Finally I tried to connect two servo and tried to work with program which skimask wrote..
Speed was ok but up-down servo vibrated again.Left-right worked well...
I think there is no error in program that you wrote skimask...
But i dont know where the problem is...
Last edited by burak450; - 4th October 2008 at 12:57.
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Try tipping your gizmo on its side, up and down becomes left and right. If that helps then counter balance.
We realy need to see your power supply! Two 7805s slower than one?
Swapping the servos had no change? The up and down servo worked correctly as the left and right servo? If so, the servo is not broken, yet.
Dave
Always wear safety glasses while programming.
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I swapped the servos and up-down servo didnt work correctly.It goes up and down but it makes vibriation...maybe that means its broken...
thats my power supply...
and thats 7805 circuit...
and thats two servos..
I think there are two possibilities about my problem
power problem or broken servo...
Last edited by burak450; - 4th October 2008 at 14:15.
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When I say swap the servos, I was meaning physically. If the up/down is used for the left/right, does the left/right action still work.
I I was wanting to see the 7805s in parallel.
But... I still think the problem is power.
The one 9volt 450ma source does not provide enough power for tho whole setup, I think.
That is 450 ma total, yes at 9 volt, start adding two or more 7805s to drop to 5 volt and try to run motors... the amps are just not available.
Do you have another source?
Dave
Always wear safety glasses while programming.
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I'd get rid of that...and I'd be willing to bet if you hooked up an o'scope to the output under a load, the output would drop off like a rock and just plain look ugly.
You'd be better off with an 8 cell AA NiMH pack of batteries. I would definitely support the load of 2 servos a lot better.
A single 9V battery (the little square ones) or even 2 connected in parallel... That just isn't going to support the load either.
And again, I see the one capacitor across what looks to be the output power and ground lines....ONE capacitor. Are there any more around there? A small cap across Vdd/Vss on the PIC? Another one across Vin/Gnd on the 7805, one across Vout/Gnd on the 7805, one on the main power input? Maybe even one across V+ and Gnd for the servo?and thats 7805 circuit...
You need more than one capacitor in a circuit for good performance...One somewhere in the circuit isn't good enough.
http://en.wikipedia.org/wiki/Decoupling_capacitor
http://www.repairfaq.org/sam/aapsfaq.htm
Well, you can waste your time by swapping servo's, trying different code, and so on...or you can get a better power supply and start making progress on your project. Your choice...I think there are two possibilities about my problem
power problem or broken servo...
Last edited by skimask; - 4th October 2008 at 17:22.
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I hope my explanation is helpful, it may be more than you are looking for but it is good to know why things are as they are.
The servo's you are using is standard size, under light load they draw about 150 mA. If you hang a 6kg weight on a cable and attach it to the servo horn (about 1cm radius) then you are drawing about 500~800 mA. Since in your setup you don't quite have that much weight, what you have is an extended mass, because of inertia the mass will resist moving at the speed that the servo circuitry is setup for. So the servo struggles to draw more current to compensate. This slowing down and speeding up causes current surges and voltage drops. That is why you see the oscillation.
The hobby servos are rated for 4.8v to 6v (grandfathered since NiCd 1.2v/cell). At 6v it will move faster than at 4.8v (0.20s/60 deg compared to 0.16s/60deg). So seeing a slowing down compared to using higher voltage is to be expected.
What test equipment do you have? Oscilloscope? Multimeter? etc...? What country are you in? is it difficult to get 9v @ 3A for example? If it is difficult then Skimask is correct in using NiMh or NiCd, or maybe even sealed lead acid (alarm system battery usually 3~6A)
Nick
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