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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 70 · 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.⬛ The threshold of a light sensor is … (a) the top speed (b) the black/white cut-off (c) the battery size (d) the wheel size
  2. 2.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  3. 3.⬛ 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) far behind it (d) under the right sensor
  4. 4.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  5. 5.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 27. What is under the sensor? (a) the white floor (b) the black line
  6. 6.🔦 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) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  7. 7.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  8. 8.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  9. 9.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 28. What is under the sensor? (a) the black line (b) the white floor
  10. 10.⬛ Why does a light sensor read a LOW number over a black line? (a) black soaks up light (b) black is loud (c) black is hot (d) black is wet
  11. 11.⬛ A reading below the threshold means the sensor is over … (a) the sky (b) white (c) water (d) black
  12. 12.🔦 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) both sensors (b) neither sensor (c) the left sensor (d) the right sensor
  13. 13.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  14. 14.🔦 A light sensor reads 20 over black and 80 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 64. What is under the sensor? (a) the black line (b) the white floor
  16. 16.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?
  17. 17.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 19. 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 30 and the right sensor reads 95. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
  19. 19.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  20. 20.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 53. What is under the sensor? (a) the black line (b) the white floor
  21. 21.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 63. What is under the sensor? (a) the white floor (b) the black line
  22. 22.🔦 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 black line (b) the white floor
  23. 23.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  24. 24.🔦 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) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
  25. 25.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  26. 26.🔦 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 left sensor (b) the right sensor (c) both sensors (d) neither sensor
  27. 27.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 10. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  28. 28.🔦 A light sensor reads 30 over black and 80 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 30 and the right sensor reads 20. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither 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 10. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  31. 31.🔦 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 black line (b) the white floor
  32. 32.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
  33. 33.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 36. What is under the sensor? (a) the white floor (b) the black line
  34. 34.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  35. 35.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 20. 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 45. What is under the sensor? (a) the black line (b) the white floor
  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 25. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left 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 60. Which sensor is over the black line? (a) both sensors (b) neither sensor (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 80. What is under the sensor? (a) the white floor (b) the black line
  40. 40.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 47. What is under the sensor? (a) the white floor (b) the black line

Answer key

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

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