Today, despite significant advances in the field of technology and production of advanced equipment, unfortunately, in most countries, the production of agricultural products is insufficient and is decreasing. Therefore, the use of new technologies in order to increase the quality and quantity of agricultural products has a particular importance. For this purpose, in this research, a system equipped with an ultrasonic sensor was used as a warning unit for the non-planting of sugarcane billets in the sugarcane planting machine. By passing the billets at different speeds (2, 2.8, 3.4 and 4.5 m/s) inside the system, the detection accuracy of the ultrasonic sensor was evaluated and the best place to install the sensor on the system was obtained. Data collection was done in a factorial experiment based on a completely randomized design, and data analysis and comparison of the averages were done by SPSS (V16) software. The results of the experiments showed that with increasing distance of the sensor from the billets falling position, the detection accuracy decreases due to increase in the billets speed. In the field tests, the system accuracy in detecting the billets passage in front of the sensor was evaluated. According to the results, a linear regression relationship with R2=0.929 was obtained between the signal announced by the system and the actual number of fallen billets in the furrow. The results indicate that the system is appropriate accuracy for monitoring of fallen billets during planting. In the field evaluation of the warning system's accuracy, the results showed that in the case of non-planted distances more than 0.5 meters, which are practically considered as the points that need to plant again, the system announces and records the position for replant correctly in %95 to %99.8 of times.