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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 42 · 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 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  2. 2.⬛ The threshold of a light sensor is … (a) the wheel size (b) the top speed (c) the battery size (d) the black/white cut-off
  3. 3.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 71. What is under the sensor? (a) the black line (b) the white floor
  4. 4.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  5. 5.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 80. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  6. 6.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 11. What is under the sensor? (a) the white floor (b) the black line
  7. 7.⬛ A reading below the threshold means the sensor is over … (a) water (b) the sky (c) white (d) black
  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 30 over a black line and above 30 over the white floor. It reads 53. What is under the sensor? (a) the white floor (b) the black line
  10. 10.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the left sensor (b) between the two sensors (c) under the right sensor (d) far behind it
  11. 11.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 65. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
  12. 12.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 59. What is under the sensor? (a) the black line (b) the white floor
  13. 13.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 37. What is under the sensor? (a) the white floor (b) the black line
  14. 14.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  15. 15.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 47. What is under the sensor? (a) the black line (b) the white floor
  16. 16.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 16. What is under the sensor? (a) the white floor (b) the black line
  17. 17.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 36. What is under the sensor? (a) the black line (b) the white floor
  18. 18.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 65. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
  19. 19.⬛ Why does a light sensor read a LOW number over a black line? (a) black is wet (b) black soaks up light (c) black is loud (d) black is hot
  20. 20.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 53. What is under the sensor? (a) the white floor (b) the black line
  21. 21.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  22. 22.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 55. What is under the sensor? (a) the white floor (b) the black line
  23. 23.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 26. What is under the sensor? (a) the white floor (b) the black line
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 20. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  25. 25.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 28. What is under the sensor? (a) the white floor (b) the black line
  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 70. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  27. 27.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  28. 28.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 60. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  29. 29.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  30. 30.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 44. 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 25 and the right sensor reads 10. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) the right sensor (d) both sensors
  32. 32.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 52. What is under the sensor? (a) the white floor (b) the black line
  33. 33.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 30. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  35. 35.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  36. 36.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 15. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  37. 37.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
  38. 38.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 80. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
  39. 39.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 56. What is under the sensor? (a) the white floor (b) the black line
  40. 40.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 30. Which sensor is over the black line? (a) both sensors (b) neither sensor (c) the right sensor (d) the left sensor

Answer key

  1. 50
  2. the black/white cut-off
  3. the white floor
  4. 55
  5. the left sensor
  6. the black line
  7. black
  8. 40
  9. the white floor
  10. between the two sensors
  11. the left sensor
  12. the white floor
  13. the black line
  14. 45
  15. the black line
  16. the black line
  17. the white floor
  18. the left sensor
  19. black soaks up light
  20. the white floor
  21. 60
  22. the white floor
  23. the black line
  24. both sensors
  25. the black line
  26. neither sensor
  27. 50
  28. the left sensor
  29. 50
  30. the black line
  31. both sensors
  32. the black line
  33. 35
  34. the right sensor
  35. both sensors
  36. the right sensor
  37. 40
  38. the left sensor
  39. the black line
  40. both sensors

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