Logarithmic to lineair.


    May 31 2011 | 10:30 am
    Hi guys,
    my mathematical skills aren't that great, so I'm hoping some one can help me with the following problem. I've connected a potentiometer to an arduino, and it returns values between 0 and 1024. The problem is that it doesn't output these values on a lineair scale, but rather in a logarithmic way.
    So I'm wondering, is there anyway to correct this? To convert log to lin?
    Any help in the right direction would help me and my colleagues a bunch. Thanks!

    • May 31 2011 | 12:47 pm
      rogier
      best&easiest way would be to get yourself a linear pot. (can't imagine rob and aart can't provide one :)
      rob
    • May 31 2011 | 3:39 pm
      Hey there,
      In case changing the pot is not an option for some reason, I would try to use lp.scampi or lp.scampf from the excellent—and free—Litter Power collection of externals. Arguments would have to be something like [lp.scampf map 0. 1024. 0. 1024. pow -1], I guess, but maybe Peter can chime in in case I am wrong. Vary the '-1' until you get the output curve you'd like.
      You'll find the objects here: http://www.bek.no/~pcastine/Litter/
      Good luck! Klaas-Jan
    • Jun 01 2011 | 5:13 am
      a few ways to experiment with an [expr] curve, you can get pretty much anything you want with enough tweaking :)