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Hi,Originally Posted by The Master
Bad news ...
The HS645 are rated 1 Amp each ... but their real problem is a very poor position holding caracteristics .
This servo is well known for its lack of precision AND its Hysteresis ...
That explains what you get as a behaviour.
Only solution is to change them ...
Try some old Futaba S9402 ( good discounts ... VERY good servos )
AND try to forget about Hitech products ... you'll really save your $$$ !!!
Alain
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Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
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IF there is the word "Problem" in your question ...
certainly the answer is " RTFM " or " RTFDataSheet " !!!
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All of these servos worked fine when i was using the Hitec servo tester. I would have thought the digital servo would be the first to complain if there were any problems but thats the only one working.
The Futaba S9402 is £65.50. I need 3 of those so its a bit expensive. Ive been looking at some Hitec HS-5625MG digital servos. They are very slightly better than the analog ones im currently using but they are digital so i shouldnt have a problem with them. They are only £35.99 each which is still gonna be expensive but not as much.
I would like to know what went wrong though. I cant believe that 3 perfectly good servos would suddenly mess up at the same time like this. They were holding their positions very well when i was first testing them. There was no buzzing and they wernt struggling to move the skull at all.
By the way, i have completely removed one of the analog servos from the skull and powered it up. Its still twitching. I think its even worse than when its in the skull
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I just remembered that i had an old Sanwa SRM-102 servo laying around. I tried plugging that in and it holds its position very well. It is a little jumpy if i try to turn the arm but this servo has always been like that.
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This is waaayyyy optimistic !!!
the test has been made by very serious guys with a high level servo tester ...
that wasn't MY experience but the ( very bad ) results of tests ...
ALL Those results have been published as a program called "Servormances" ... only available in French, halas.
Here you can get it ...
http://www.teaser.fr/~osegouin/aeromode/servos.phtml
You ALSO can ask P. Cesarrato a "kit" of his servo tester ... he sells it @ " friend price " ( no much more than the components price ...)
I join some description of the used tester manual ...
Add to that I have been dealing with R/C stuff for ... over 40 years. If I tell you to forget about Hitech products, It's ALSO because I personnaly have tested, repaired ... and thrown their products to the Wastebox !!!
Want some copies of the ( constructive ...) mails I've sent to and received from their technical staff ???
They even do agree their servos are " not so good " ... and , of course, always promise they will correct them !!!
Talking price ...
you can get much, much better prices ( ~ half what you tell !!! )... but may be NOT from your local reseller or any " robotics shop " !!!
Also have a look to Futaba S3302 ...
Alain
Last edited by Acetronics2; - 4th August 2010 at 22:40.
************************************************** ***********************
Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
************************************************** ***********************
IF there is the word "Problem" in your question ...
certainly the answer is " RTFM " or " RTFDataSheet " !!!
*****************************************
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So far i have got my old Sanwas from www.rapidonline.co.uk and my new Hitec servos from www.servoshop.co.uk. There isnt a local place i can go to and buy any but if you can recommend a website (preferably in the UK) then i will have a look.
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Hmm, Even if these servos arnt very good i still dont believe that 3 brand new ones would suddenly fail in the same way at the same time. There must be some reason behind it. My biggest worry is that i spend yet more money on more expensive servos and only get the same problem
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All three might fail at the same time being they are all driven by the same in-correct code? You have already stated that the code was not good and with out the servos connected to the MCU all was well...
Dave
Always wear safety glasses while programming.
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Thats true. The code was originally wrong. It was causing very short pauses of about 6ms. I assume digital servos are fine with really short gaps but could something like that actually break the servos? Or could it just be that the invalid code caused the initial buzzing and the heat caused the rest of the damage?
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