The aim of this paper is to develop a hardware Random Number Generator (RNG) by using an optical Theremin. Theremin is a noncontact electronic musical instrument based on the principle of heterodyne. It has two antennas to control volume and pitch of the sound which form a pair of resonant RLC oscillators. In the presented system, optical sensors (Photodiodes) have been used to produce the notes of the Theremin by varying the intensity of incident light beam. Two photodiodes have been used for this purpose to control gain and pitch of the sound notes. These sound waves are then sampled to give amplitude levels which forms the desired Random Number Sequence and is unique for every tune produced by the Theremin. Since random numbers are at the core of all encryption algorithms and network security such as SSH/SSL, generating high-entropy random numbers is the prime need of the hour.