This work reports novel true random number generator (TRNG) using Cu/GO/Pt memristive stack. The volatile regime of the device is utilized to achieve natural stochasticity between the switching cycles. Efficient Arduino based circuit is built and connected to the memristor to produce the data with low power and cost overheads. National Institute of Standards and Technology (NIST) tests are used to assess the randomness of the generated bits. The produced data passes all NIST tests without the post processing steps used by most of the true random number generators reported in the literature. Flexibility is a unique feature of the device reported in this work, being fabricated on flexible polymer substrate.