The present invention discloses a modular millet-hay separator equipped with a multi-stage air-assisted separation system, designed to efficiently separate hay from millet grains. Conventional grain separation methods often involve manual labour and lack precision, leading to inefficiencies and incomplete separation. In contrast, the disclosed device offers an automated and accurate solution to this challenge. Comprising nine detachable parts, the device features a cone-shaped input that channels the grain mixture into three stages of tunnels. These tunnels incorporate air blowers of varying speeds to control the quality of separation, thereby minimizing false positives and ensuring precise results. Further, a self-cleaning mechanism integrated into the tunnels. Dedicated collection boxes for both hay and millet facilitate the retrieval of separated grains. The millet collection box includes three lids for convenient access to pure millets, while the hay collection box features a wire mesh to allow excess air to escape. This innovative millet-hay separator represents a significant advancement in agricultural processing technology. Its automated operation and precise control over the separation process offer farmers and grain producers an efficient and reliable solution for separating hay from millet grains, ultimately enhancing productivity and crop yield.