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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 145 · 40 questions
TalentJR

Robot tip (Below the threshold is black): Reading below the threshold → black; above → white. Threshold = (black reading + white reading) ÷ 2. Two sensors: the one that reads black is over the line; both white → the line is between them.

NameDateTime takenScore ___ / 40
  1. 1.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
  2. 2.⬛ The threshold of a light sensor is … (a) the battery size (b) the black/white cut-off (c) the top speed (d) the wheel size
  3. 3.⬛ Why does a light sensor read a LOW number over a black line? (a) black soaks up light (b) black is loud (c) black is hot (d) black is wet
  4. 4.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  5. 5.⬛ A reading below the threshold means the sensor is over … (a) water (b) the sky (c) white (d) black
  6. 6.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  7. 7.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 30. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  8. 8.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  9. 9.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 42. What is under the sensor? (a) the black line (b) the white floor
  10. 10.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 24. What is under the sensor? (a) the white floor (b) the black line
  11. 11.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?
  12. 12.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 75. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
  13. 13.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  14. 14.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 33. What is under the sensor? (a) the black line (b) the white floor
  15. 15.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  16. 16.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  17. 17.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 95. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  18. 18.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 60. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  19. 19.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  20. 20.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 18. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 64. What is under the sensor? (a) the black line (b) the white floor
  22. 22.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 30. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
  23. 23.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 70. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  25. 25.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 30. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  26. 26.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 95. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) neither sensor (d) the right sensor
  27. 27.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 51. What is under the sensor? (a) the black line (b) the white floor
  28. 28.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 70. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  29. 29.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 52. What is under the sensor? (a) the black line (b) the white floor
  30. 30.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 45. What is under the sensor? (a) the white floor (b) the black line
  31. 31.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 75. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  32. 32.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 72. What is under the sensor? (a) the white floor (b) the black line
  33. 33.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 55. What is under the sensor? (a) the white floor (b) the black line
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 85. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
  35. 35.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 73. What is under the sensor? (a) the black line (b) the white floor
  36. 36.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 35. What is under the sensor? (a) the black line (b) the white floor
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
  38. 38.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 95. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  39. 39.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the left sensor (b) far behind it (c) between the two sensors (d) under the right sensor
  40. 40.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 63. What is under the sensor? (a) the white floor (b) the black line

Answer key

  1. 50
  2. the black/white cut-off
  3. black soaks up light
  4. 45
  5. black
  6. 45
  7. the right sensor
  8. 40
  9. the black line
  10. the black line
  11. 60
  12. neither sensor
  13. 50
  14. the black line
  15. 35
  16. 45
  17. the left sensor
  18. the left sensor
  19. 50
  20. the black line
  21. the white floor
  22. both sensors
  23. 65
  24. neither sensor
  25. the right sensor
  26. neither sensor
  27. the white floor
  28. neither sensor
  29. the white floor
  30. the white floor
  31. the left sensor
  32. the white floor
  33. the white floor
  34. the left sensor
  35. the white floor
  36. the black line
  37. the right sensor
  38. the left sensor
  39. between the two sensors
  40. the white floor

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