[etoys-dev] Join us for a sprint week before Squeakfest in July!

K. K. Subramaniam subbukk at gmail.com
Fri Apr 23 22:06:52 EDT 2010

On Thursday 22 April 2010 12:28:43 am Steve Thomas wrote:
> This sounds like fun.  I found the World "sound level" and "sound pitch",
> what needs to be done so kids can use their voices to change these
> parameters?
Sound level is related to volume, so with:
    forward: world sound level / 10.
you can make an etoy move faster by shouting louder or stop it with silence. 
If you set:
   turn by: (World sound pitch - 500) / 100

then you can get it to spin around by screaming or whistling different tunes at 
it. Tweak the magic numbers to your taste.

The idea here is to help children discover that sound has numeric properties 
too and these properties can influence other properties like color, geometry or 

Once students get the hang of it, you can introduce the concept of 

    value = previous value*t + current value*(1-t).
    previous value = value.

where t is fraction in the range 0 .. 1.

Get some ear plugs :-) .. Subbu 

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