Design of Processing Unit:
We started the design of our processing unit with the microcontroller AT89c51,which has been interfaced with the lcd as shown in the figure:
Here microcontroller process every input data from “reed switch” through the optocouplar, optocoupler just used as a electicle isolation from reed switch. When wheel rotate the read switch count the every cycle and it out put a pulse,this pulse comes to the microcontroller's (AT89C52) P3.4 and P3.5, when any input comes to P3.4 timer T0.1 start to count, and counter start to count. After 1 secend the counted data goes to out put port P1, and its show in 16x2 LCD, after 1 sec the counter and timer reset again to count the next secend data. And this process goes on, there is a another counter which count the whole input pulse and multiply with the fixt number which is redious of the wheel or disk, which's speed we are counting, and its as goes to the out put pic in middle of the counting second and its shows to the 2nd row of the 16x2 LCD panel. Whis total data is the total distance. And its reset autometically when its reach the maximum of the memory.