Solarbotics BEAM Robotics Kit 2, Руководство пользователя

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Solarbotics
PHOTOPOPPER
4.2
BEAM
Photovore
Solarbotics
PHOTOPOPPER
4.2
BEAM
Photovore
Solarbotics
PHOTOPOPPER
4.2
BEAM
Photovore
Solarbotics
PHOTOPOPPER
4.2
BEAM Photovore
Critter Overview - Why it Does what it Does
As previously discussed, this BEAM robot uses only solar energy to make its way around the environment you place it
in. The solarcell used in this particular application has just enough power to run one of the motors continually in direct
sunlight, but what good would this do you when the sun goes behind a cloud, or you want your robot to do something
else besides spin in circles? The trick is in the use of the Solarengine. It stores the power generated by the solarcell in a
capacitor, which is like a mini-battery, and very efficient. When the capacitor charges up to a particular level (in this
instance, between 2.4 and 2.7 volts), the Solarengine activates, and throws all the stored energy from the capacitor to
the motor. This makes the motor spin good and fast, much more so than if it were connected to the solarcell by itself.
To make the Photopopper phototropic (attracted to light), the robot has to decide which direction has the most light.
This Photovore design uses a pair of light-sensors arranged like a bridge to make this decision. Think of it this way:
Imagine a level see-saw with a water bucket at each end. When a raincloud comes near, it starts filling the buckets with
water, but the one nearest the cloud fills up faster. As soon as the one bucket fills, it makes it's end touch down and spill
out. Using this analogy, the buckets are the light-sensors, the raincloud is the source of light, and the spilling out is the
signal for the proper Solarengine to trigger. You will be able to set the “see-saw point” using the trimmer potentiometer
so your Photopopper will go straight towards light sources. Or if you want, you can tweak it so that it will “prefer” to
turn one way versus the other simply by changing the way the two light-sensors “balance” each other on their
electronic see-saw.
The light-sensors are very good at what they do. They're designed to view a 100 degree angle, and will not let the
Photopopper get itself caught in a shadow while there are better sources of light nearby. One of my favourite past-
times when I torment (um, I mean observe) my Photopoppers is to herd them around their pen using a shadow cast
by my hand, or a book. Sometimes they aren't tricked, and will try to jump through the shadow to where the light
looks better!
The touch-sensors you will be building will give the Photopopper the ability to avoid obstacles in its way that it didn't
“see” with the optics. These sensors work in a simple manner - they shut off the Solarengine controlling the motor on
the opposite side. When the Photopopper bumps into something against it's left sensor, it shuts down the right side's
motor. This makes the Photopopper pivot around the right motor until the sensor comes free, and then the robot
continues on it's merry way.
There is an exception to this rule, and that is when both sensors have been activated. Unfortunately, the Photopopper
isn't smart enough to know how to back out of a trouble spot, so in this case it will ignore the touch-sensors and try to
bully it's way through the obstacle with brute force. It may not seem like it would have a chance against another
BEAMbot or obstacle in a display area, but it will probably surprise you. Slow, but steady, consistant attempts can prove
to work quite well. Just don't blame it for knocking your flower vase off the shelf (it was the cat's fault - honest!).
3
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1381 1381
3 3
2 2 1 1
2.2k 2.2k 100k
680k 680k
.22 F
m
.22 F
m
3300 F
m
2N3904 2N3904
2N3906 2N3906