Abstract : The technology of using 80C196KC as micro2controller to realize automatic weighing and mixture ma2 terials with the magnetic plate is introduced ,and the application of resistance strain sensor and working principle of apparatus are presentd ;hardware and idea of designing software presentd emphatically. At the same time the output signal process of resistance strain sensor and the trigger circuit of SCR has been described detailedly. Key words :resistance strain sensor ; magnetic plate ; SCR ; trigger pulse