Tree Measurer
Project
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Opening Activity
How do you make paper without
cutting down the forest?
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Tree Farming
•
Trees are grown and
harvested in renewable
cycles to produce wood
products for human use
•
Tree plantations can
sometimes be established
on abandoned farmland so
existing forest does not have
to be cleared
Profitable Reforestation
Some trees are grown with
the intent to sell the wood, then donate
the land to become a protected forest
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Tree Farming
Most tree farms exist for
commercial use
– These farms tend to grow only
one type of tree, usually for
paper or lumber
– A monoculture (one-species
ecosystem) is not the same as
a natural forest ecosystem
– However, the use of tree
plantations may reduce the
need to clear forest to supply
wood products
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
Tree Harvest
A Christmas tree farm will harvest its crop
in time to ship to distributors and
plant new trees for future seasons.
© 2006 Carnegie Mellon Robotics Academy
Tree Farming
Tree farms, like all
plantations, need to be
economically viable
– Labor costs are always
a concern
– The amount of time taken to
monitor the growth of young
trees is substantial
– Can more advanced tools
assist in the measurement
process?
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
Measuring trees
Traditional measurement techniques can be
time-consuming for large numbers of trees
© 2006 Carnegie Mellon Robotics Academy
Tree Measurer:
Programming Review
Data Hubs & Wires
Display Block
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Data Hubs & Wires
Many blocks have data hubs which
can be opened by clicking the notch in
the lower-left corner of the block.
A data hub contains many data plugs,
which allow information to flow in and
out of the block.
Data wires control the flow of data
between blocks.
Output plugs typically send out a
sensor value, or the result of a
computation.
Such information usually goes into
another block’s input plug, allowing
the reading or result to be used as a
value inside the block.
Speed Controlled by Sensor
Ultrasonic Sensor distance output plug controls
the value of the Move Block’s power setting
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Display Block: Number
The Display Block displays
images or text on the NXT’s
LCD display.
The Display Block does not
have built-in support for
displaying Numbers. In order
to display a Number, you must
first convert it to Text using the
Number to Text Block.
The Display Block must also be
configured to display Text, or it
will ignore the wired-in value.
Display Ultrasonic Sensor Value
Ultrasonic Sensor reading is converted to Text
then displayed on the NXT’s LCD screen
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy
Summary
• Trees can be grown on plantations to
reduce the need to cut down existing
natural forests
• A faster measuring device for trees could
save time and labor costs
• Data hubs and wires allow important
information to flow between different blocks in
a program
• Numbers can be displayed on the NXT’s LCD
display, but must be converted using the
Number to Text Block first
Designed for use with the LEGO MINDSTORMS® Education NXT Software and Base Set #9797
© 2006 Carnegie Mellon Robotics Academy