Hi , I use Basic stamp 2,
my code
'
do
for counter = 1 to 30
pulsout 12, 850
pause 10
pulsout 12, 650
pause 20
next
loop
and it just turning CW
and not turn CCW
even i do 750 it still turn CW
it look like just one way turnning.
First off the code you have will make the servo vibrate and move in one direction. You need to give it a pulseout value and a 20ms pause AND THEN THE SAME VALUE AGAIN and a pause. Take out the pause 10 and the pulseout 12, 650 then change the other pulseout from 650 to 850 in steps. Also you need to find the point where the servo stops or adjust it to stop at 750 if you have an external adjustment like the parallax servos do.
Hi thanks for quick reply,
i try what you say , but it like the servo just turn only one direction,
do
pulsout 12, 850
loop
then i replace 850 with 650 the servo still turn same direction and 750 is just vibrate ,
my servo it HS785HB from hitec it 360o servo
The HS-785HB servo is not a continuous rotation servo. It is a sail winch servo that turns 1.75 revolutions each way.
Hitec and Futaba are different when it comes to what they consider center. For Most, including Hitec, center is 1.500 milliseconds. For Futaba center is 1.520 milliseconds.
Unless you have modified this servo, no, it will not work for a wheel.
Tomvn said...
Hi Rich H
can you show me, how modified this servo to continuous rotation serv?
I wish I could! The arrangement of the pot on this servo is going to be different than most because the output gear can rotate multiple times before coming to a stop - using either a multi-turn pot or an additional gear. I have not seen a photo or diagram of how the pot is arranged to allow this. What you need to do is physically disconnect the pot from the gear train while the servo is centered, secure the pot from moving and remove any stops. Difficulty in making the mod could range from easy to very hard to near impossible. I just don't know.
There are many tutorials on modding servos, Here's one.
i am having the same problem with this servo, it will take the first direction but fail to respond to each additional command. i think it must be potentimeter be cause it makes more than one rotation the signal is incorrect for the servo. im going to try to get it to work if i can. if not im going back to futaba.
What you describe doesn't make sense. As far as the servo is concerned, there is no such thing as a "command". There is only a pulse width which the servo mechanism constantly compares to the position of the servo. If the pulse width is different from the servo position, the motor is driven to correct the servo position. In the case of a winch servo like this one, the servo position is over a roughly 630 degree range.
Per Rich, that is a sail winch servo with 3.5 rotations. That's a specialized (and relatively pricey) part. Save it for the right application. Better & cheaper to mod a standard 180-degree servo. 1/4 scale servos can be had on Ebay as low as $10.
Tomvn
Posts: 103
Comments
What version of Stamp are you using? And what code are you testing?
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
my code
'
do
for counter = 1 to 30
pulsout 12, 850
pause 10
pulsout 12, 650
pause 20
next
loop
and it just turning CW
and not turn CCW
even i do 750 it still turn CW
it look like just one way turnning.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen
i try what you say , but it like the servo just turn only one direction,
do
pulsout 12, 850
loop
then i replace 850 with 650 the servo still turn same direction and 750 is just vibrate ,
my servo it HS785HB from hitec it 360o servo
Hitec and Futaba are different when it comes to what they consider center. For Most, including Hitec, center is 1.500 milliseconds. For Futaba center is 1.520 milliseconds.
Unless you have modified this servo, no, it will not work for a wheel.
Rich H
can you show me, how modified this servo to continuous rotation serv?
I wish I could! The arrangement of the pot on this servo is going to be different than most because the output gear can rotate multiple times before coming to a stop - using either a multi-turn pot or an additional gear. I have not seen a photo or diagram of how the pot is arranged to allow this. What you need to do is physically disconnect the pot from the gear train while the servo is centered, secure the pot from moving and remove any stops. Difficulty in making the mod could range from easy to very hard to near impossible. I just don't know.
There are many tutorials on modding servos, Here's one.
Rich H
Post Edited (W9GFO) : 6/16/2009 5:50:01 PM GMT
Per Rich, that is a sail winch servo with 3.5 rotations. That's a specialized (and relatively pricey) part. Save it for the right application. Better & cheaper to mod a standard 180-degree servo. 1/4 scale servos can be had on Ebay as low as $10.