27404 Parallax Inc, 27404 Datasheet - Page 88

• Manufacturer Part Number: 27404
• Description: COMPETITION RING FOR SUMOBOT
• Manufacturer: Parallax Inc

Specifications of 27404

• Accessory Type: Hobby and Education
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: SumoBot®
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Your Turn - Headlight Adjustments
A small change in the direction the SumoBot's IR LEDs are pointing can make a huge
difference in its performance. Remember this when testing the competition code at the
end of chapter 4 and the datalogging code at the end of Chapter 5. You will probably
find yourself adjusting the direction each IR LED points to get the most consistent
detection of your opponent.
For the programs in this text, you should start by pointing the IR LEDs straight ahead.
Pointing the IR LEDs outward can cause the SumoBot to not realize its opponent is
straight in front of it because both IR detectors can't see the opponent at the same time.
Pointing the IR LEDs inward can result in the SumoBot thinking the opponent is on it's
front right, when it is in fact on its front left (and visa-versa). Pointing the IR LEDs
upward can result in missing an opponent because the headlights are too high.
One adjustment that can be useful is pointing the IR LEDs slightly downward. The angle
should be very slight, certainly not more than 5° below horizontal when viewed from the
side. When viewed from the top, the IR LEDs should still be pointing straight ahead,
there should be no detectable angle outward or inward.
The slight downward angle can be helpful during the part of a round when the SumoBots
are pushing against each other. As they push against each other, sometimes both the
SumoBots tip upward briefly. At this moment, if the IR LEDs are not tilting slightly
down, it can cause even the SumoBot with the advantage to think its opponent is no
longer in front of it. Its program might cause it to change from lunging forward to
executing a search pattern, which will in turn cause it to give up its advantage.
Certain SumoBots may benefit from very slight outward or inward adjustments as well.
This again will be a trail and error experiment you can try in Chapter 4, Activity #6 and
also during Chapter 5, Activity #4.
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With TestFrontIrObjectDetectors.bs2, try pushing the SumoBots against each
other to create the symptom just described.
Try to tilt the IR LEDs so that it still sees its opponent if it has the plow
advantage (Chapter 1, Activity #1), and so that it loses sight of its opponent if it
has the plow disadvantage.
Make a note to yourself to revisit this issue during Chapter 4, Activity #6 and
also during Chapter 5, Activity #4.