Subject:
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Re: Help with events
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 27 Feb 2003 23:48:23 GMT
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Original-From:
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Steve Baker <sjbaker1@ANTISPAMairmail.net>
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Viewed:
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2151 times
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Camp0s wrote:
> Hy to all,
>
> i was just trying to do a robot which can help me and my friends in the lab
> school. We are doing measures on a pendulum (if the word is right), the
> teacher said that we have to do about 450 readings of the time which the
> pendulum makes 20 go and back from right to left (you know what a mean). Now
> it's a repetitive, precision and boring task. So a thought why not telling
> my favourite Lego brick to do the job right for me ?
Yes - an excellent job for automation.
> I put a light back to the pendulum and the brick with the light sensor in
> front of it.
>
> I setted and up Event to react when the pendulum cover the light beam and
> the light sensor read a darker value.
>
> SetSensor (SENSOR_2, SENSOR_LIGHT);
> SetEvent (1,SENSOR_2,EVENT_TYPE_LOW);
> SetLowerLimit(1,50);
> SetUpperLimit(1,80);
>
> This is what a first written in BricxCC, BUT, i'm getting a:
>
> "Undefined variable EVENT_TYPE_LOW"
>
> What does this mean ?
I thought it was 'EVENT_TYPE_PRESSED' - but then I didn't think it worked
with light sensors. Did you tell the compiler to make the code for RCX 2?
I don't think there is event support in RCX 1.
> And do you have any other suggestion on how to have better readings of the
> pendulum oscillations ? Maybe not using events ?
I would have used two tasks. Have one detect the pendulum:
int ticked ;
task Pendulum ()
{
while ( 1 )
{
while ( SENSOR_2 > whatever )
{
/* DO NOTHING */
}
ticked = TRUE ;
while ( SENSOR_2 < whatever_plus_a_bit )
{
/* DO NOTHING */
}
}
Have the other tell the time whenever the pendulum task sets 'ticked'
to TRUE:
task Timer ()
{
int time = 0 ;
ticked = FALSE ;
start Pendulum ;
while ( 1 )
{
wait ( 1 ) ;
time++ ;
if ( ticked )
{
...do something with the time...
ticked = FALSE ;
time = 0 ;
}
}
}
Set 'whatever' and 'whatever_plus_a_bit' appropriately for the light
levels you are seeing (or better still, make it auto-calibrate).
---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1@airmail.net> WorkEmail: <sjbaker@link.com>
HomePage : http://www.sjbaker.org
Projects : http://plib.sf.net http://tuxaqfh.sf.net
http://tuxkart.sf.net http://prettypoly.sf.net
-----BEGIN GEEK CODE BLOCK-----
GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M- V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++
-----END GEEK CODE BLOCK-----
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Message is in Reply To:
 | | Help with events
|
| Hy to all, i was just trying to do a robot which can help me and my friends in the lab school. We are doing measures on a pendulum (if the word is right), the teacher said that we have to do about 450 readings of the time which the pendulum makes 20 (...) (24 years ago, 27-Feb-03, to lugnet.robotics)
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