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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 595 · 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 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  2. 2.⬛ 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 wet (d) black is loud
  3. 3.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  4. 4.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?
  5. 5.⬛ 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
  6. 6.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) far behind it (b) between the two sensors (c) under the left sensor (d) under the right sensor
  7. 7.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) white (c) water (d) black
  8. 8.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  9. 9.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  10. 10.🔦 A light sensor reads 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  11. 11.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 37. What is under the sensor? (a) the black line (b) the white floor
  12. 12.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  13. 13.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 53. What is under the sensor? (a) the black line (b) the white floor
  14. 14.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 95. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
  15. 15.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 7. 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 44. 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 11. 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 20 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  19. 19.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 15. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  20. 20.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 56. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
  22. 22.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 22. What is under the sensor? (a) the black line (b) the white floor
  23. 23.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 41. What is under the sensor? (a) the white floor (b) the black line
  24. 24.🔦 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 black line (b) the white floor
  25. 25.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  26. 26.🔦 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 black line (b) the white floor
  27. 27.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 63. What is under the sensor? (a) the white floor (b) the black line
  28. 28.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 35. What is under the sensor? (a) the white floor (b) the black line
  29. 29.🔦 A light sensor reads 10 over black and 60 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 67. What is under the sensor? (a) the black line (b) the white floor
  31. 31.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  32. 32.🔦 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
  33. 33.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 60 and the right sensor reads 60. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
  34. 34.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  35. 35.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 33. What is under the sensor? (a) the black line (b) the white floor
  36. 36.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 60. What is under the sensor? (a) the white floor (b) the black line
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 75. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  38. 38.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
  39. 39.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 47. What is under the sensor? (a) the black line (b) the white floor
  40. 40.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 10 and the right sensor reads 65. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) both sensors (d) the left sensor

Answer key

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

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