摘要：This paper focuses on the use of the touchpad （key）, STC89C51RC monolithic integrated circuit PWM control signal, which changed the traditional mechanical buttons as a DC motor rotational speed and steering control method. Touch switch advantages compared with the traditional mechanical switches are： first, the quieter second, more sensitive; third, faster; four, long life and so on. Specialized chips are also used in the article the PWM signal system, and the principle of PWM signal, method and how the software adjust the duty cycle of the PWM signal to control its input signal waveforms are are described in detail. In addition, this article also introduced consisting of triode amplifier circuit of h-bridge amplifier as a DC motor driving module, enabling the control of DC motor speed. On the software side, PI was described in detail in the article arithmetic program initializes write ideas and specific programs such as program implementation.