The acquisition of heart rate variability (HRV) signals is very important to physiological research and clinical diagnosis. In order to ensure the accuracy of acquired heart rate variability signals, we must consider the method of acquisition of heart rate variability signals. By using the relation between the signal singularity and its wavelet transforms, a software for R wave in detection is designed. The result is very satisfying in detecting R wave of ECG database of MIT/BIH.