Nyquist rate determination and oversampling I'm new to this. I'm using ShannonGui to generate a sine wave with a $1\textrm{ Hz}$ signal frequency.

From what I can tell to determine the Nyquist rate I need to double the highest frequency, since it's a constant $1\textrm{ Hz}$, I just double it and get a Nyquist rate of $2\textrm{ Hz}$ correct?

Now I also read that the Nyquist rate is the lowest frequency that you can use as a sampling frequency to avoid aliasing, but when I use $2\textrm{ Hz}$ as the sample frequency the reconstructed wave is a straight line at 0. So does this mean the Nyquist rate is wrong or my understanding of it is wrong?
you actually have to sample at more than twice the highest frequency.  if $B$ is the bandwidth or highest frequency and $f_\text{s}$ is the sampling frequency, then to satisfy the Sampling Theorem (for normal baseband sampling):

$$ 2B &lt; f_\text{s} $$

it is not

$$ 2B \le f_\text{s} $$

sampling at exactly twice the frequency of a sinusoid is "critically sampling" and loses amplitude or phase.  it can't get both.  in your case, it is sampling the sinusoid when it crosses zero.