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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 443 · 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.⬛ The threshold of a light sensor is … (a) the black/white cut-off (b) the top speed (c) the battery size (d) the wheel size
  3. 3.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  4. 4.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  5. 5.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 45. What is under the sensor? (a) the black line (b) the white floor
  6. 6.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) white (c) water (d) black
  7. 7.🔦 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 white floor (b) the black line
  8. 8.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 39. What is under the sensor? (a) the black line (b) the white floor
  9. 9.⬛ Why does a light sensor read a LOW number over a black line? (a) black is loud (b) black is hot (c) black is wet (d) black soaks up light
  10. 10.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 29. What is under the sensor? (a) the white floor (b) the black line
  11. 11.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 75. What is under the sensor? (a) the white floor (b) the black line
  12. 12.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 85. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) both sensors (d) the left sensor
  13. 13.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 27. What is under the sensor? (a) the black line (b) the white floor
  14. 14.⬛ 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
  15. 15.🔦 A light sensor reads 10 over black and 80 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 20 and the right sensor reads 65. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  18. 18.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 54. What is under the sensor? (a) the white floor (b) the black line
  19. 19.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 36. What is under the sensor? (a) the black line (b) the white floor
  20. 20.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 54. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  22. 22.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 85. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) neither sensor (d) both sensors
  23. 23.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 70. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) the right sensor (d) both sensors
  24. 24.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 78. What is under the sensor? (a) the black line (b) the white floor
  25. 25.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 29. What is under the sensor? (a) the black line (b) the white floor
  26. 26.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 64. 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 39. What is under the sensor? (a) the black line (b) the white floor
  28. 28.🔦 A light sensor reads 10 over black and 70 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 40 and the right sensor reads 70. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  30. 30.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 85. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  31. 31.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  32. 32.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  33. 33.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  34. 34.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 43. What is under the sensor? (a) the black line (b) the white floor
  35. 35.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 30. What is under the sensor? (a) the white floor (b) the black line
  36. 36.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 15. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
  37. 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 35 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
  38. 38.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 58. What is under the sensor? (a) the black line (b) the white floor
  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 20. What is under the sensor? (a) the white floor (b) the black line

Answer key

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

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