Ramsey Electronics Walking Electronic Bug WEB1 - Manual (Page 15)

WEB1 • 15
2. Steering adjust:
A. The first step in adjusting the steering is to get the steering motor,
(the one that’s mounted at an angle) to come on when the bug
approaches an obstacle, or when someone shines a flashlight at
it. The first thing is to bend the Infrared phototransistor Q2, and
Infrared LED D3 as shown in the picture. Bend them down and
inward towards each other so they kind of look like the bug’s man-
dibles or something, ha ha. These two components are how the
WEB1 detects an object. The infrared LED emits infrared light,
and the infrared phototransistor detects infrared light. Hmm, how
could these two be used as an obstacle detector? Well, normally
the LED is shining out into the room and Q2 is off. When the bug
gets close to a wall (important note: not a BLACK wall), some of
the infrared light from the LED bounces off of the obstacle and
hits Q2. Then Q2 turns on, and the angled motor turns on and
makes the bug turn. A black or very dark obstacle may not cause
the bug to turn because it absorbs the infrared light instead of re-
flecting it.
B. The next step is to bring your hand or other everyday object near
the front of the bug when it is switched on. What should happen is
that the turning motor (the angled one) should come on when the
object gets close. If it’s on already, that means that Q2 and D3 are
too close. Just move them apart a little. If the turning motor is on
no matter what you do, THEN ALL IS LOST!!!!!!!!!! Well, actually
no, just turn down the sensitivity (adjust R5 counterclockwise).
Then adjust the distance between Q2 and D3 until the motor turns
on only when an obstacle is in front of the WEB1. An important
note here is that adjusting the sensitivity will be more critical if
there is bright incandescent light or a lot of sunlight at your loca-
tion. This is because they give off infrared light that Q2 picks up.
Fluorescent lights give off very little if any infrared light and hardly
affect the WEB1 at all. Further, a HeNe laser doesn’t give off any
infrared light, so if your school or home is lit with laser light you’re
all set!