Datasheet

Page 88· Applied Robotics with the SumoBot
Testing for Electrical Continuity
The leads on the IR LEDs and receivers tend to be thinner than jumper wires and other
component leads. The X8 and X9 sockets on some SumoBot boards may also have
sockets with slightly larger holes than the ones in the breadboard. A resulting loose fit
could be a problem for some IR LEDs and detectors. During a match, vibration can
cause brief electrical continuity interruptions between the IR component pins and the
header sockets. This in turn can result in the SumoBot losing sight of its opponent, or
maybe never even catching a glimpse.
Electrical Continuity is when there's a continuous pathway through which current can flow.
If two conductive metals are firmly pressed against each other, it provides electrical
continuity. If the pieces of metal are separated briefly, current can no longer flow, and
electrical continuity is interrupted.
Sometimes skin oils or surface oxidation on the metal can prevent the actual conductive
parts of the metal from making contact. The act of inserting a lead into a breadboard socket
typically abrades the surfaces enough to establish electrical continuity.
Continuity Tests
√ Remove one of the IR components from either the X8 or X9 header, and make a
note of how much force you used. Did it slide right out, or did the socket kind of
gently grip the components leads and resist the component's removal?
Especially if the component slid right out, the leads will lose contact (electrical
continuity) during the jostling and vibration of a sumo match.
√ If you are unsure if the socket gripped the leads firmly enough, compare it to
removing the same component from the breadboard sockets.
If it's way easier to remove the component from the X8/X9 header than it is to remove it
from the breadboard, it's also a good indicator that there will continuity problems during
a match.
√ Repeat for each component in the X8/X9 headers.
Ensuring Continuity
The SumoBot Robot Competition Kit may have extra components that are not used in the
activities in this book, such as 10 µF capacitors. The leads on these spare capacitors or