Manipulating a servo
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Posts: 46,084
There might be a problem with the 15' per hour design you have in mind.
Most "standard" RC servos do not rotate a full 360', so if you do 15'/hr
times 24 hrs = 360 degrees. If you want to do this "around the clock",
you'll probably run out range of what the servo will "seek" to.
Also, most servos are not designed for "continuous rotation", so you
would have to "reset" the servo to it's initial state at some point
(around 12 hours I think). I have heard that some sail-winch servos will
rotate the full 360', and some people use a torque multiplier to get a
wider range of motion and more strength at the expense of speed. look
here: <http://tinyurl.com/2n8nt> , that doesn't work go to
http://www.robotzone.com and look for "Servo Power Gear Boxes".
As for the code, depending upon what level of accuracy you need, you
could write a very small "wait" loop for the BSII to "sit " in and then
adjust the number of iterations required to get 1 minute of "delay", then
multiply that number to find out how many iterations = 1 hour. I think
this would drift a bit with temp (Jon might be able to give you a better
way to do this) but it would be "free" as opposed to buying a more
accurate external clock.
Speaking of external clocks, [noparse]:)[/noparse] another approach would be to use the
"pocket watch" module
<http://www.parallax.com/detail.asp?product_id=27962>, it's a serial real
time clock that can be queried to determine the time. Write a BSII
program to check the clock and if the last two digits ="00" then
increment the servo position, if not go back to sleep for 1 second, then
query again.
Hope this helps [noparse];)[/noparse]
Vern
--
Vern Graner CNE/CNA/SSE | "If the network is down, then you're
Senior Systems Engineer | obviously incompetent so why are we
Texas Information Services | paying you? Of course, if the network
http://www.txis.com | is up, then we obviously don't need
Austin Office 512 328-8947 | you, so why are we paying you?" ©VLG
Newzed@a... said:
> In a message dated 5/3/2004 9:59:19 AM Eastern Daylight Time,
> uebermenchens@a... writes:
>
>
>> Is it possible to maipulate a servo to rotate 15 degrees per hour?
>> If so how would I go about doing it??
>>
>
> Pulse your servo plus 1 from last pulse. In other words, pulse 775, 776,
> 777, and so on to determine how many pulses it takes to move your servo
> 15
> degrees. Divide 60 minutes by the number of pulses and that will give you
> the
> pause between pulses.
>
> Sid Weaver
> I2C on a BS2 platform.................
> http://www.visualmuses.com/chipcircuit/index.html
>
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>
Most "standard" RC servos do not rotate a full 360', so if you do 15'/hr
times 24 hrs = 360 degrees. If you want to do this "around the clock",
you'll probably run out range of what the servo will "seek" to.
Also, most servos are not designed for "continuous rotation", so you
would have to "reset" the servo to it's initial state at some point
(around 12 hours I think). I have heard that some sail-winch servos will
rotate the full 360', and some people use a torque multiplier to get a
wider range of motion and more strength at the expense of speed. look
here: <http://tinyurl.com/2n8nt> , that doesn't work go to
http://www.robotzone.com and look for "Servo Power Gear Boxes".
As for the code, depending upon what level of accuracy you need, you
could write a very small "wait" loop for the BSII to "sit " in and then
adjust the number of iterations required to get 1 minute of "delay", then
multiply that number to find out how many iterations = 1 hour. I think
this would drift a bit with temp (Jon might be able to give you a better
way to do this) but it would be "free" as opposed to buying a more
accurate external clock.
Speaking of external clocks, [noparse]:)[/noparse] another approach would be to use the
"pocket watch" module
<http://www.parallax.com/detail.asp?product_id=27962>, it's a serial real
time clock that can be queried to determine the time. Write a BSII
program to check the clock and if the last two digits ="00" then
increment the servo position, if not go back to sleep for 1 second, then
query again.
Hope this helps [noparse];)[/noparse]
Vern
--
Vern Graner CNE/CNA/SSE | "If the network is down, then you're
Senior Systems Engineer | obviously incompetent so why are we
Texas Information Services | paying you? Of course, if the network
http://www.txis.com | is up, then we obviously don't need
Austin Office 512 328-8947 | you, so why are we paying you?" ©VLG
Newzed@a... said:
> In a message dated 5/3/2004 9:59:19 AM Eastern Daylight Time,
> uebermenchens@a... writes:
>
>
>> Is it possible to maipulate a servo to rotate 15 degrees per hour?
>> If so how would I go about doing it??
>>
>
> Pulse your servo plus 1 from last pulse. In other words, pulse 775, 776,
> 777, and so on to determine how many pulses it takes to move your servo
> 15
> degrees. Divide 60 minutes by the number of pulses and that will give you
> the
> pause between pulses.
>
> Sid Weaver
> I2C on a BS2 platform.................
> http://www.visualmuses.com/chipcircuit/index.html
>
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
>