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Boe-Bot whiskers circuit explanation — Parallax Forums

Boe-Bot whiskers circuit explanation

dcapacitordcapacitor Posts: 2
edited 2011-12-27 15:57 in BASIC Stamp
Chapter 5 of Robotics with the Boe-Bot includes a schematic for connecting the whiskers on page 149. I understand the purpose of 10k pull-up resistors in the circuit, but what is the purpose of the 220 resistors attached to the input pins?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2011-12-27 15:38
    The 220 Ohm resistors are there for protection against programming errors and will limit the current through the I/O pin to a safe value if you accidentally make the I/O pin a high output while the whisker contact is connected to ground.
  • dcapacitordcapacitor Posts: 2
    edited 2011-12-27 15:57
    Makes sense. Thanks, Mike!
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