© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Tree Measurer Project

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Opening Activity How do you make paper without cutting down the forest?

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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 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 Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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? Measuring trees Traditional measurement techniques can be time-consuming for large numbers of trees

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 Tree Measurer: Programming Review Data Hubs & Wires Display Block

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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

© 2006 Carnegie Mellon Robotics Academy Designed for use with the LEGO MINDSTORMS ® Education NXT Software and Base Set #9797 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 Summary 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