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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 14 · 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 reading below the threshold means the sensor is over … (a) water (b) black (c) white (d) the sky
  2. 2.⬛ The threshold of a light sensor is … (a) the battery size (b) the wheel size (c) the top speed (d) the black/white cut-off
  3. 3.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 10. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) neither sensor (d) the left sensor
  4. 4.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the right sensor (b) under the left sensor (c) far behind it (d) between the two sensors
  5. 5.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  6. 6.🔦 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
  7. 7.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 15. 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 80 and the right sensor reads 90. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  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 black line (b) the white floor
  10. 10.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  11. 11.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  12. 12.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 43. What is under the sensor? (a) the black line (b) the white floor
  13. 13.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 25. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  14. 14.🔦 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) both sensors (c) neither sensor (d) the right sensor
  15. 15.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  16. 16.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 35. What is under the sensor? (a) the black line (b) the white floor
  17. 17.⬛ Why does a light sensor read a LOW number over a black line? (a) black is hot (b) black is wet (c) black soaks up light (d) black is loud
  18. 18.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  19. 19.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 25. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
  20. 20.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  21. 21.🔦 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) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  22. 22.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 16. What is under the sensor? (a) the black line (b) the white floor
  23. 23.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 90. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 10. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  25. 25.🔦 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
  26. 26.🔦 A light sensor reads 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  27. 27.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 20. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
  28. 28.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 74. What is under the sensor? (a) the white floor (b) the black line
  29. 29.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 43. What is under the sensor? (a) the white floor (b) the black line
  30. 30.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 23. What is under the sensor? (a) the black line (b) the white floor
  31. 31.🔦 A light sensor reads 10 over black and 70 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 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 85 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
  34. 34.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 39. What is under the sensor? (a) the white floor (b) the black line
  35. 35.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 65. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
  36. 36.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  37. 37.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  38. 38.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 38. What is under the sensor? (a) the black line (b) the white floor
  39. 39.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 52. What is under the sensor? (a) the black line (b) the white floor
  40. 40.🔦 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 white floor (b) the black line

Answer key

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

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