From: Caleb Tennis <caleb@...>
Date: 2005-11-23T07:40:07+09:00
Subject: Re: How convert an integer to a bit array

>
>
> s = ""
> s[0] = 7
> s.unpack("B*")[0].split("").map{|bit|bit.to_i}
> => [0, 0, 0, 0, 0, 1, 1, 1]
>
>
>
> It should be easier than that, though.
>

How about:

num = 50

num.to_s(2).split("").map{ |bit| bit.to_i}

There's problably some trickery with String.each_with_index you can  
do to make the map a little simpler.