Wall Follower





Name of Activity Wall Follower
Author Jay Clark
Keywords NXTs, car, wall, distance, loops, conditional loops, sensor, threshold
Subject NXTs
Grade Level 4, 5, 6, 7, 8, 9+
Time 1 Hour Total
Brief Description Students will program their NXT cars to follow the outer edge of the classroom by driving along the wall at a set distance away.
Lesson Objectives: Programming using loops and conditional loops
Determining and Implementing sensor thresholds
Materials Needed: Prebuilt NXT car with a sound sensor
Clear wall space
Computers with NXT Mindstorms software
Preparation and Set Up: Find a section of the room that has the most dynamic wall. -Maybe the wall juts out for a closet and back in again afterwards-

Clear this space for cars to run next to.

For any inside turns (turning to the right if the wall is on your left), place a strip of black tape a foot or so away from the wall for the extensions.

Necessary Background A wall follower activity is very similar to the line follower programmatically. Start close to the wall. Turn away from the wall until the distance sensor reads that you are too far, then drive back towards the wall until the distance sensor reads that you are too close. Loop.

There is a challenge in trying to get the car to make an outside turn. This involves playing with the distance away from the wall you set your car to follow, and how dramatically you have the car steer.

Inside turns cannot be made using the loop. Some other sensor must tell the car that an inside turn is approaching, and then the car must react by turning. Students may use a touch sensor, a light sensor, a sound sensor, or even another distance sensor (if they have one)

Vocabulary: Threshold – The sensor value that when breached, will trigger a wait for block or a conditional loop. (Some students have had a better time understanding it as a “benchmark”)

Procedure Introduction – 10 minutes Introduce/ Review loops with the students and why they are useful in programs.

  • Loops allow us to repeat a set of commands that would otherwise be tedious to program over and over.

Introduce the activity, and ask the students if they have an idea of what the program should look like. Activity – 40 minutes Allow students to make the mistake of not including any turns in their program. They will understand their mistake when trying to make the first outside turn. Clean up/ Wrap up – 10 minutes

  • What was easiest? What was hardest?
  •  What would you have done differently?
  •  What were some good ideas you saw that other groups came up with?
Extensions: In order to make inside turns, students will have to use a conditional loop and another sensor to warn them of the upcoming turn.
Reference 1 http://sites.tufts.edu/stompactivitydatabase/files/formidable/c1.jpg
Reference 2 http://sites.tufts.edu/stompactivitydatabase/files/formidable/d.png

NXT Alarm





Name of Activity NXT Alarm
Author STOMP
Keywords alarm, sensor, security, NXT, proximity, ultrasonic sensor
Subject NXTs
Grade Level 4, 5, 6, 7, 8, 9+
Time 1 Hour Total
Brief Description Build and program a security system using an NXT. The alarm should be triggered by the proximity (ultrasonic) sensor.
Lesson Objectives: - To learn about programming using the proximity sensor.
- To apply programming to real life problems.
Materials Needed: One NXT brick per group
One or more proximity sensor per group
Assortment of pieces to attach proximity sensor
Computers running MINDSTORMS NXT software
Preparation and Set Up: Set up computers running NXT Software.

Arrange students in groups of two.

Distribute necessary materials.

Necessary Background Programming is used in real life situations. Programming is used in a wide variety of devices to enhance our lives in terms of safety, ease, entertainment, transportation, etc. This activity is a good example of a way that programming can be used in the real world.
  1. Have student design an alarm box that will detect when a person approaches the box. If students want to use more than one proximity sensor or a different sensor as well they should be allowed to be creative.
  2. Allow students to decide how their security system will respond when someone approaches (display something on the screen, make a noise, drive away)
  3. Have students program the NXT to respond when someone approaches the proximity sensor and to stop responding when that person backs off.
    1. The entire program will need to be looped so that the NXT is always secure
    2. When the NXT is not being threated it should signal that it is alarmed by displaying “system alarmed” on the NXT screen.
    3. When the proximity sensor senses that an object is near it should respond (say by displaying back off! and playing a tone).
    4. The alarm should be looped until the proximity sensor no longer detects an object close to it.
  4. Students may use more than one sensor to trigger the alarm.
  5. Allow students to test and redesign their prototypes.
Extensions: Use multiple sensors to trigger the alarm. Have a different response for each
Build an NXT alarm clock or timer.
Attach the NXT alarm to a diary or box. Build something to keep people from opening the diary/box.
Program the NXT so that a user needs to enter a security code to turn off the alarm.
Reference 1 http://sites.tufts.edu/stompactivitydatabase/files/formidable/64_image_2.png
Reference 2 http://sites.tufts.edu/stompactivitydatabase/files/formidable/64_image_6.jpg
Reference 3 http://sites.tufts.edu/stompactivitydatabase/files/formidable/Engineering_Design_Process2.doc
Reference 4 http://sites.tufts.edu/stompactivitydatabase/files/formidable/NXT_alarm.doc

Digital Measuring Wheel





Name of Activity Digital Measuring Wheel
Author STOMP
Keywords NXT, rotation, sensor, measurement, accuracy, diameter, circumference, pi, distance, conversion
Subject NXTs
Grade Level 4, 5, 6, 7, 8, 9+
Time 1 Hour Total
Brief Description Use an NXT and a rotation sensor to buld a digital measuring wheel. The device can be
pushed by hand on the ground or at a distance using a handle. Check the device’s
accuracy with a measuring tape.
Lesson Objectives: - To learn about programming in NXT MINDSTORMS.
- To use measurements and math in programming to collect data.
Materials Needed: NXT brick
NXT motor w/built in rotation sensor
LEGO wheel and axle
Computers running NXT-G MINSTORMS software.
USB cords to connect NXT bricks to computers
Data collection sheet
Preparation and Set Up:
- Arrange students in groups of two.

- Distribute necessary materials.
- Distribute a data collection sheet.

Necessary Background Measuring wheels are used in many places to find the distance of a line. The number of
rotations can be translated to distance if the circumference of the wheel is known.
The circumference can be found by measuring around a wheel or by multiplying the
diameter by pi.


  1. Have students build a measuring wheel device. Attach a wheel with an axle to a motor. Wire the motor to the NXT brick, but do not attach the motor to the NXT brick.
  2. Have students measure the wheel’s circumference to use when calculating distance.
    1. Option: You may also have the students find the circumference by measuring the diameter and multiplying the diameter by pi.
    2. Option: You may also discuss radius by having students multiply the radius by 2 x pi to get teh circumference
    3. Option: Have students find the circumference all three ways and compare answers.
  3. Have students program the NXT brick to display the distance traveled by doing the following:
    1. Divide the rotation degrees value by 360 to get the number of rotations traveled (or have the rotation sensor count in rotations) using the “Math” Block.
    2. Multiply that value by the circumference to get a distance value by using the “Math” block.
    3. Convert this distance value to a text value using a “Number to Text” block.
    4. Display the text value on the NXT screen using a “Display” block.
    5. You will need to enclose the program in a loop so that it is continuously displaying measurement data
  4. Check the accuracy of the device with a tape measure by having students measure the length of different lines.
  5. Discuss, as a class, reasons that the measurement may not be accurate. Does this always matter? How could you make the measurement more accurate?
  6. Discuss the different variables in this experiment.
    1. The independent variable is the number of rotations.
    2. The dependent variable is the measurement shown on the screen.
    3. Discuss as a class the relationship between these two variables.
    4. Option: draw a line graph of rotations v. acutal measurement (inches, cm, meters, etc.) that the NXT brick displays.
  7. Discuss where a measuring wheel might be useful and where it is not useful. What other tools can be used to measure distance?
Extensions or Modifications: Add a touch sensor to clear data to take a new measurement.
Use a touch sensor to trigger when measurements are displayed.
Add sound feedback when certain distances are reached.
Convert the device to a wench that measures the length of a string wrapped
around it
Reference 1 http://sites.tufts.edu/stompactivitydatabase/files/formidable/58_image_2_tet.png
Reference 2 http://sites.tufts.edu/stompactivitydatabase/files/formidable/58_image_3.jpg
Reference 3 http://sites.tufts.edu/stompactivitydatabase/files/formidable/Digital-Measuring-Wheel.pdf
Reference 4 http://sites.tufts.edu/stompactivitydatabase/files/formidable/Engineering_Design_Process.doc
Reference 5 http://sites.tufts.edu/stompactivitydatabase/files/formidable/measure_worksheet.doc
Reference 6 http://sites.tufts.edu/stompactivitydatabase/files/formidable/Measuring_wheel.doc

Mousetrap Problem





Name of Activity Mousetrap – Problem
Author Terry Greene, Merredith Portsmore, Abe Gissen
Keywords Engineering Design Process, problem, research, brainstorm, mousetrap, motor, sensor
Subject Non-LEGO
Grade Level K, 1, 2, 3
Time 2 Hours Total
Brief Description Students will use steps of the Engineering Design Process to learn about a problem; Identify the Problem, Research the Problem, Brainstorm Possible Solutions. Students will be able to describe the need for mousetraps, different type of mousetraps and possible ways to trap a mouse.

The design challenge is for the students to work as a class to design and build a mousetrap sculpture that has at least nine movable parts, which are connected together. Small groups will work on each part. Each part must use one motor and one sensor.

Lesson Objectives: To understand the steps of the Engineering Design Process
Materials Needed: Mousetrap Game by Milton Bradley
Poster of the design process
Easel with plenty of paper for drafting
Preparation and Set Up: Set up the classroom for easy classroom discussion.
Make a poster of the Engineering Design Process to use as an aid.
  1. Have the students play the Mousetrap Game by Milton Bradley.
  2. In a large group, discuss engineering:
    1. Ask if anyone knows an engineer.
    2. Ask what an engineer does
    3. Discuss what engineers do and what kinds of jobs use engineers.
  3. Display the steps of the Engineering Design Process. Go over each step on the poster and explain that, over the next few weeks, students will use all the steps; working like engineers to complete a challenge.
  4. Discuss the Mousetrap Game
    1. Ask individuals to share their favorite part of the game.
    2. Make connections to simple machines.
    3. Ask students how an engineer might have been involved in designing the game.
  5. Present the design challenge
    1. Tell the students that they are engineers working for a toy company.
    2. They have been asked to design a new toy to be modeled after the Mousetrap Game.
    3. The design challenge is for the students to work as a class to design and build a mousetrap sculpture that has at least nine movable parts, which are connected together. Small groups will work on each part. Each part must use one motor and one sensor.
    4. Explain that the students have already completed steps 1 and 2 of the Engineering Design Process
      1. Identify the Need/Problem
        1. By listening to what the teacher has assigned as the design challenge.
      2. Research the Need/Problem
        1. By playing the game.
  6. Have student brainstorm possible solutions (step 3 of the Engineering Design Process). Draw on math and science to articulate the solutions in two and three dimensions.
  7. Use an easel to record ideas and brainstorm possible ideas for different parts of the mousetrap.
  8. Try to make a list of about 25 possible parts of a mousetrap.
  9. Save these ideas for Day 2.

Day 2:

  1. Review the brainstorming session the class participated in on Day 1.
  2. Explain that the next step in the Engineering Design Process is to Select the Best Possible Solution to the Problem.
  3. Brainstorm a list of criteria for the mousetrap with the students.
  4. Go through the list of original parts and cross out ones that do not meet the criteria.
  5. Set up teams of students (usually 2 works best).
  6. Have each team talk about the different parts and decide on 2 – 3 that they would like to build.
  7. As a large group (whole class), decide which team will build which part of the mousetrap and record this on the easel.
Reference 1 http://sites.tufts.edu/stompactivitydatabase/files/formidable/1ideascriteria-1.doc
Reference 2 http://sites.tufts.edu/stompactivitydatabase/files/formidable/1ideascriteria.doc
Reference 3 http://sites.tufts.edu/stompactivitydatabase/files/formidable/mousetrapoverview.doc
Online Reference(s) http://www.ceeo.tufts.edu/robolabatceeo/-CEEOCurriculumWebsite
Umbrella Unit/Curriculum (if applicable) Mousetrap

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