Robotics with the Boe-Bot text v2.2

Chapter 7: Navigating with Infrared Headlights · Page 255
ACTIVITY #6: THE DROP-OFF DETECTOR
Up until now, the Boe-Bot has mainly been programmed to take evasive maneuvers when
an object is detected. There are also applications where the Boe-Bot must take evasive
action when an object is not detected. For example, if the Boe-Bot is roaming on a table,
its IR detectors might be looking down at the table surface as shown in Figure 7-8. The
program should make it continue forward so long as both IR detectors can “see” the
surface of the table. In other words, the Boe-Bot can continue forward so long as the
table top it’s navigating on is detected.
√ Disconnect power from your board and servos.
√ Point your IR pairs downward and outward as shown in Figure 7-8.
Figure 7-8
IR Pairs
Directed
Downwards to
Scan for a
Drop-Off
Top View Side View
Recommended Materials:
(1) Roll of black vinyl electrical tape – ¾″ (19 mm) wide.
(1) Sheet of white poster board – 22 x 28 in (56 x 71 cm).
Simulating a Drop-Off with Electrical Tape
A sheet of white poster board with a border made of electrical tape makes for a handy
way to simulate the drop-off presented by a table edge, with much less risk to your Boe-
Bot.
P15
P14
P13
P12
P11
P10
P9
P8
P4
P2
P1
P0
P7
P6
P5
P3
X2
X3
Vdd Vss Vin
Board of Education
© 2000-2003
Rev C
Vdd
Black
Red
X4 X5
15 14 13 12
To Servos
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