How far will the BOE-BOT move?

• How far will the BOE-BOT move?

• The manual (Robotics, Version 2.2) says that the program on the previous page will run each servo for about 3 seconds. Let’s see why:

• FOR Counter = 1 TO 122

• PULSOUT 13, 850 ‘sets P13 high for 850*2 us = 1.7 ms

• PULSOUT 12, 650 ‘sets P12 HIGH for 650*2 us = 1.3 ms

• PAUSE 20 ‘pause for 20 ms

• NEXT

• The total time per loop is 1.7 + 1.3 + 20 = 23 ms plus a small amount of time for the BASIC Stamp to execute the instructions. The BASIC Stamp 2 executes 4000 instructions/second or each instruction takes about 0.25 ms. The five instructions in the loop will take about 1.25 ms, so the total time per loop is really about 24.25 ms.

• So the total time for the program is (24.25 ms/loop)(122 loops) = 2.96 seconds

• If the wheels have a diameter D = 2.5” then the circumference C = D = 7.854”

• If the BOE-BOT servos turn a maximum of 30 rpm, then the distance traveled in 2.96 seconds is

• Distance = (30 rev/min)*(1min/60 sec)*(7.854”/rev)(2.96 sec) = 11.62”