Abstract Random numbers are very important in many fields of computer science. Generating high-quality random numbers using only basic arithmetic operations is challenging, especially for devices with limited hardware capabilities, such as Internet of Things (IoT) devices. In this paper, we present a novel pseudorandom number generator, the simple chain automaton random number generator (SCARNG), based on compositions of abstract automata. The main advantage of the presented algorithm is its simple structure that can be implemented easily for very low computing capacity IoT systems, FPGAs or GPU hardware. The generated random numbers demonstrate promising statistical behavior and satisfy the NIST statistical suite requirements, highlighting the potential of the SCARNG for practical applications.