servo motor resets 16f877a

[burak450]

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...

[mackrackit]

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?

[skimask]

thats my power supply...

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 thats 7805 circuit...

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?
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

I think there are two possibilities about my problem
power problem or broken servo...

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...

[Macgman2000]

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

[burak450]

First of all I read everything you wrote.I will go to buy a new power supply (9V 3A or more) and will use more caps as soon as possible...I havent got Oscilloscope,i have only a multimeter...

But tonight I found out a new thing...

I wrote a code to test servo broken or not....

TRISC=0
i var byte
BASLA:

for i=0 to 25
PAUSEUS 19500
pulsout PORTC.2,50

next 
pause 4000

for i=0 to 25
PAUSEUS 19000
pulsout PORTC.2,100

next 
pause 4000

for i=0 to 25
PAUSEUS 18500
pulsout PORTC.2,150

next 
pause 4000

for i=0 to 25
PAUSEUS 18650
pulsout PORTC.2,135

next 
pause 4000

for i=0 to 25
PAUSEUS 18000
pulsout PORTC.2,200

next 
pause 4000


GOTO BASLA
END

I connected first power supply 5.2V 2.5 A without 7805 and saw that...

Servo didnt vibrated at values pulsout 50 and 100 but at 150 and 135 made vibration and finally at 200 didnt make vibration...

Thats its video:http://www.dailymotion.com/burak450/...-52-v-25a_tech

Secondly,I connected power supply 9v 450mA with 7805.Servo came at 50 position and couldnt move 100 and 150 position.I was very very suprised here.After that servo moved 135 position and made vibration!!!!
Finally moved 200 with no vibration!!!

That its video http://www.dailymotion.com/burak450/...with-7805_tech

What do you think gentlemen?

Broken servo or only power problem???

[skimask]

Tough to hear the servo's in those videos...sure the video is low quality, but I think the audio is more important here...
As far as the servo's vibrating/not vibrating... I think when your servo hit there limits (which is where I hear the constant whining) you won't have any vibration because it can't vibrate.
I think what you really have to do is take those servo's off of that 'turret' and figure out where the limits of those servo's really are so you don't confuse a 'no vibration' condition with a servo that's hit it's mechanical (and/or electrical) limit. A pulse width of 1000-2000us for this servo, might not be good for that servo...or it might be just fine.

[burak450]

Hi guys,

I bought 9v 3.5 A power supply but Only problem that i have "vibration" is still same...

It is so weird,up-down motor vibrates only some values....

I dont know what to do but I think I gotta take off up-down motor...

Maybe these values are limits of servo as skimask said...

I will connect up-down motor to left-right motor with different way so I can use values which didnt make vibration for up-down motion....

Thats the only solution that I can find...

Any other ideas????

[mackrackit]

I bought 9v 3.5 A power supply but Only problem that i have "vibration" is still same...

Have you changed the regulators also? To handle the extra amps...

I will connect up-down motor to left-right motor with different way so I can use values which didnt make vibration for up-down motion....

Have you tried laying the apparatus on it side to see if the up/down servo works correctly?

Any other ideas????

Have you tried counter balancing the up/down servo?