Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: the jeenyus on May 08, 2009, 05:59:34 PM
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Hello. I a question regarding the operation of my remote... No matter how much I adjust the trims, the servos do not stop rotating, only varying in speed. Am I doing something wrong? Is there another way to adjust trims?
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can you please explain a bit more? i really don't get your question that much...
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OK sorry... What I mean is on the transmitter there are 4 different trims for 4 different channels (please correct me if I am wrong, by the way) and while attempting to adjust the trims so the servos stop moving, the servos do not completely stop. What do I have to do to adjust the trims correctly?
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ahh, i see where your coming from now!
do you have access to an oscilloscope?
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The servos are probably modified incorrectly. With the trims in the center position it should send out a centering pulse of 1.5ms - if your servos are moving then they are not centered properly.
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do you have any extra servos to test it with? unmodified/modified properly?
if your servos are bunged out you will have to remodify them by removing the glue and doing it again or
placing 2 2k2 resistors where the pot was...
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the trim on a radio transmitter will only fine tune the servo controll/direction. I am guessing you are using modified servo's from the $50 robot? If you are then basically those servos were callabrated to be not turning at 1.5ms. Depending on what your transmitter/receiver outputs will determine if the servo moves or not.
I have got this same situation myself because i thought an rc transmitter would output 1.5ms when the stick was centered.
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The incorrect modification of my servos is a distinct possibility. I will re-modify them I guess. How would I remove Crazy Glue? What type resistors? 22k (x2)?
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you can either get rid of the glue with a solvent of some kind and re-center the servo or
take the pot off completely and solder two 2k2 (2.2K) resistors in its place...
see http://www.narobo.com/articles/ModServos.html (http://www.narobo.com/articles/ModServos.html) for the second option.
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Thank you very much. I will replace the pot. I greatly appreciate your advice. I will post the results.
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that's what we are here for ;)
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I am attempting to solder on the 2 2.2k resistors, but the picture on that link is not very clear on exactly where to put them. Also, the PCB on my hitec hs-311 servo is different than the one pictured. Please help me find where to put them correctly.
Thank you very much
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where the pot was there should be three wires...
the two outer holes have one leg of the resistor in them...
the middle hole has the second legs of the resistors...
see the picture...
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Oh ok. thank you. I feel so stupid lol. It seems so obvious... But in the pic it looks like a big bundle of leads....
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nah, sometimes it very hard to tell with no schematic ;)
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Hello sorry to bother you again, but upon the unsoldering of the servo, I accientially took off a part of the bright green stuff on the pcb... which i think is bad in the electronics world... is there any way I can salvage this servo do you think? The danger with this is that I do not know what it connects to, for it disappears under the black IC looking thing. I also do not know if it was supposed to be bridged with anything adjacent. I apologize for the poor quality of the pic, my digital camera sucks. It is the best pic of like 50 I could come up with...
Please help me!!!
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First off, did you take off any copper traces? If not, did you damage any parts?
P.S. Does your camera have a macro setting? (should be the mode that shows a little picture of a flower)
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nvm i fixed it! yay!
By the way do you know of any retail store I would be able to find a 3 channel hitec surface transmitter? I would like to get one but dont want to order online right now...
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Check your local hobby shop, because I don't think there are any really wide spread retail stores that would sell them.
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Ok thank you I will check.
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Look for the airplane transmitters, because I see a lot of them that come with a bunch of micro servos aswell. ;D Also they usually have a few more channels that come stock with them.
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i thought he was looking for a surface transmitter?
there is a difference between them... if you are flying get an air frequency transmitter...
if on ground eg car, truck.. get a ground frequency...
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That is the "legal" way to do it... but it's not like any one cares.... :P There aren't any good surface transmitters for land besides 2.4ghz which is okay for both land and air.
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That is the "legal" way to do it... but it's not like any one cares.... :P There aren't any good surface transmitters for land besides 2.4ghz which is okay for both land and air.
Just make sure you don't see any rc aircraft in the area, and keep your antenna folded in as much as you can.
Fortunately, as of a year or so ago, they now sell good surface transmitters:
http://www.servocity.com/html/transmitters___radio_packages.html (http://www.servocity.com/html/transmitters___radio_packages.html)