Seeder machines in agricultural operations may face real-time problems of plugging due to stubble, stones or unusually large seeds. This paper aims at detecting blockages in the seed tube using an ultrasonic sensor and reporting the same to a smartphone application. The ultrasonic sensor transmits sound waves and uses delay in the received echo signal to measure distance from the sensor to the obstacle (either the flowing seed or the opposite wall of the nozzle). Based on the calculated distance, the flow of seeds through the nozzle can be detected. One such sensor will be placed on each row unit and all these sensors will continuously communicate with a central controller (also placed on the seeder). The sensors will report nozzle-blockage to the controller and the controller will then immediately notify the same to the smartphone user via a graphical real-time application. Looking at the application window, the user will get real-time information about the blocked nozzle in the seeder.