Design of Precise Detection System for Wheat Seeding Quantity Based on AD7746 Analog to Digital Conversion Chip

This paper develops a precise detection system for wheat-planter seeding quantity based on the AD7746 analog to digital conversion chip. The corresponding parallel plates was designed to improve the detecting accuracy of the capacitance sensor. Then, the relationship between capacitance value and the quantity of wheat seeds under two modes of single-seed falling and several-seed falling was investigated in detail. For the mode of single-seed falling, a differential dynamic threshold method was proposed to detect the number of wheat seeds. The experiment results indicated the maximum relative error was 1.538%. For the mode of several-seed falling, the partial least-squares regression model between the number of wheat seeds and the integral quantity of capacitance was established to confirm the detecting accuracy. The experiment results shown that high detecting accuracy was achieved with different seeding speeds, and the relative error was between-2.24% and 2.01%. Consequently, the proposed system can achieve high detection accuracy under the different seeding mode and different seeding speed.