[squeakland] [Squeakland News] How to do timing in Etoys?
richi.moran at gmail.com
Wed Sep 10 16:51:53 EDT 2014
I wrote about this same subject a couple of weeks ago:
My approach is a little different, though. I like Etoys ability to
represent concepts visually, and I think time is one of those concepts :)
The example I chose is about Physical Etoys because I see this question
come up very often when programming robots (and also because I
had an old video of a simple traffic light built with leds that I wanted to
use), but of course it applies to any Etoys project.
I'm planning to write a follow up to that article but using the Playfield's
timer instead. I think each approach has its own merits so if you don't
mind I'll post a link to your blog.
On Thu, Sep 4, 2014 at 10:32 AM, Rita <ritafreudenberg at googlemail.com>
> I just got this question from my students and I thought there might be
> others with similar interests. So how can I control sequences of actions
> over time? Say, I want to use speech bubbles to tell a story. I have a
> number of sentences to show, one after another, and I want to let some time
> pass between them to give the reader time to read. How can I do that?
> Well, I can build a timer and check the time to trigger actions when a
> certain time is reached. How can I build a timer?
> First of all, you need a variable to count time steps. Open the viewer for
> your object. Create a variable by clicking the "v" - symbol in the top row
> of the viewer and give your variable a name. I choose "seconds". The
> default type is "Number", which is fine and 0 decimals places are perfect
> as well.
> Now open a new empty script and drag the tiles to assign a new value to
> your variable into the script. Change the operation to "increase by" and
> the number to "1". Make sure the value of your variable is "0" at the
> start! Name the script "timer".
> You do know already that the script, once started, will be executed
> repeatedly until it is being stopped, right? Do you also know how fast or
> how slowly this happens? You can see this when you click on the watch in
> the top row of the scriptor and hold the mouse button down. And you can
> also change it there! By default, it will be executed 8 times per second.
> Change this into once per second!
> When you now start the script, each second it will increase the value of
> your variable "seconds" by 1! Now you can use the value of the variable in
> other scripts:
> Use a all-scripts-tile from the supplies to start both, your script and
> the timer, at the same time and watch :)
> *Please note:* It depends on your computer and what other programs are
> running on it at the same time, if a second in the Etoys project will be
> the same as a second at a real clock. It may not be exactly the same, but
> probably close. It is definitely good enough to control the flow of a
> story, but for scientific experiments, you should use a real timer!
> You can also find a tutorial to build a timer in project 6 of the book
> "Powerful Ideas in the classroom" by Kim Rose and B.J. Allen-Conn.
> Von Rita am 9/04/2014 06:32:00 vorm. unter Squeakland News
> squeakland mailing list
> squeakland at squeakland.org
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