A device for measuring an absolute angle includes first and second rotatable members having first and second radii and capable of rotating over first and second angles respectively, a first number of detectable elements mounted on the first rotatable member, a second number of detectable elements mounted on the second rotatable member, and at least one sensor for detecting rotation of the detectable elements. The second rotatable member is coupled with the first rotatable member such that the second angle is equal to the first angle times the ratio of the first radius and the second radius. The first radius is equal to a first integer times a factor, while the second radius is equal to a second integer times the factor. The product of the first number and the second integer, and the product of the second number and the first integer, are co-prime.