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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 638 · 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 90 over white. A good threshold is halfway between them. What is it?
  2. 2.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 42. What is under the sensor? (a) the black line (b) the white floor
  3. 3.⬛ The threshold of a light sensor is … (a) the wheel size (b) the black/white cut-off (c) the top speed (d) the battery size
  4. 4.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 40. What is under the sensor? (a) the white floor (b) the black line
  5. 5.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 60. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
  6. 6.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 26. What is under the sensor? (a) the white floor (b) the black line
  7. 7.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 66. What is under the sensor? (a) the black line (b) the white floor
  8. 8.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 85. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
  9. 9.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) black (c) white (d) water
  10. 10.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is 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) both sensors (b) the left sensor (c) neither sensor (d) the right sensor
  12. 12.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  13. 13.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 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
  14. 14.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  15. 15.⬛ Why does a light sensor read a LOW number over a black line? (a) black is hot (b) black soaks up light (c) black is loud (d) black is wet
  16. 16.🔦 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 black line (b) the white floor
  17. 17.🔦 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
  18. 18.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 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
  19. 19.🔦 A light sensor reads 10 over black and 70 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 25. What is under the sensor? (a) the white floor (b) the black line
  21. 21.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 10. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  22. 22.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 68. What is under the sensor? (a) the white floor (b) the black line
  23. 23.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  24. 24.🔦 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 white floor (b) the black line
  25. 25.🔦 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 black line (b) the white floor
  26. 26.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the left sensor (b) far behind it (c) under the right sensor (d) between the two sensors
  27. 27.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  28. 28.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  29. 29.🔦 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) neither sensor (c) both sensors (d) the right sensor
  30. 30.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 58. What is under the sensor? (a) the black line (b) the white floor
  31. 31.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 49. What is under the sensor? (a) the black line (b) the white floor
  32. 32.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 46. What is under the sensor? (a) the black line (b) the white floor
  33. 33.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 30. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  34. 34.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  35. 35.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  36. 36.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 80. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) neither sensor (d) the right sensor
  38. 38.🔦 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) neither sensor (b) both sensors (c) the right sensor (d) the left sensor
  39. 39.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 54. What is under the sensor? (a) the black line (b) the white floor
  40. 40.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 13. What is under the sensor? (a) the white floor (b) the black line

Answer key

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

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