In this research, a simple and an innovative design of triboelectric nanogenerator (TENG) is reported that converts impact response in electrical signal. The two contacts of vertical separation mode TENG consist of Al and nanostructured PDMS with integral spacer of 1.5 mm. The feature size of 80 nm PDMS domes was achieved by replicating nanostructured aluminum. The performance of the device was measured by applying the mechanical pulses of 4 kgf at frequency of 3 Hz. The fabricated TENG demonstrated 0.73 mW output power at load resistance of 10(7) Omega. The nanostructured PDMS TENG was successfully used as self-powered impact sensor by falling small objects on it. The impact force of 1 g metallic ball from different height was calculated directly from the output voltage of TENG which showed an outstanding correlation with impact force calculated from workenergy theorem.