Answer Key: NXT Test Circuits (View Mode) Worksheet

Submitted by Randy Steele on 12 July, 2011 - 12:28

Answer Key: View Mode Worksheet

1. Touch Sensor

  •  The display changes from “0” to “1” when the touch sensor is pressed.
  •  The“1” represents the touch sensor is pressed (switch closed) and the “0” not pressed (switch open).

2. Light Sensor

  • The red LED illuminates in Reflected Light mode and the display shows a value as a percentage.
    • The value represents the amount of light reflecting back to the sensor.
    •  As the sensor approaches a surface, the amount of reflected light increases, however, once the sensor touches the surface the value can decrease again due to the plastic divider between the LED and sensor.
       
  • In Ambient Light mode the LED is turned off and the display shows a value as a percentage.
    • The value represents the amount of light striking the sensor.
    •   Ambient Light mode uses the light that is naturally in the environment, Reflected Light mode adds its own light with the LED.

3. Ultrasonic Sensor

  • Ultrasonic Inch mode - display shows a value in inches indicating how far away the sensor is from an object (note: the sensor is some distance inside the plastic housing, so the distance displayed is a little further than the front of the sensor).
    • The sensor works best with a hard, flat object placed parallel to the sensor’s front face (note: ultrasound is just high frequency sound – think about how sound can be absorbed by soft surfaces or bounce off hard surfaces).
  • Ultrasonic-CM mode - the behavior is the same, the display is just calibrated in centimeters instead of inches.

4. Sound Sensor

  • This sound sensor for NXT is capable of measuring the relative loudness of the robot's environment, returning a value up to 100%.  The Lego sound sensor is not calibrated in decibels (dB). 
  • The dB mode responds to all frequencies of sounds, whereas and dBA mode only responds to sounds in the human audible range (approximately 20 - 20 KHz).

5. Motor

  • Motor-Rot - in 'rotation' mode, the display shows a value in rotations indicating many times the orange motor hub has been turned. The display starts at “0” and counts both up and down as the motor is turned in opposite directions.  The display will show negative rotations if turned below “0”.
  • Motor-Deg - in 'degrees'  mode, the behavior is the same. The display is just calibrated in degrees instead of rotations.  One rotation of the orange hub is equal to 360 degrees.  Rotation mode is most useful for large movements and Degrees mode is better for small movements.