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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 215 · 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 60 over white. A good threshold is halfway between them. What is it?
  2. 2.⬛ The threshold of a light sensor is … (a) the wheel size (b) the battery size (c) the top speed (d) the black/white cut-off
  3. 3.🔦 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
  4. 4.🔦 A light sensor reads 20 over black and 80 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 54. What is under the sensor? (a) the black line (b) the white floor
  6. 6.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 30. What is under the sensor? (a) the white floor (b) the black line
  7. 7.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 65. Which sensor is over the black line? (a) the left sensor (b) neither sensor (c) both sensors (d) the right sensor
  8. 8.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 49. What is under the sensor? (a) the white floor (b) the black line
  9. 9.⬛ A reading below the threshold means the sensor is over … (a) black (b) the sky (c) white (d) water
  10. 10.🔦 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
  11. 11.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 12. What is under the sensor? (a) the black line (b) the white floor
  12. 12.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 70. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) the left sensor (d) neither sensor
  13. 13.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
  14. 14.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 90. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the left sensor (d) the right sensor
  15. 15.🔦 A light sensor reads 10 over black and 70 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 23. What is under the sensor? (a) the white floor (b) the black line
  17. 17.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 45. 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 25 and the right sensor reads 20. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
  19. 19.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) between the two sensors (b) under the left sensor (c) far behind it (d) under the right sensor
  20. 20.⬛ 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
  21. 21.🔦 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 black line (b) the white floor
  22. 22.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
  23. 23.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 27. What is under the sensor? (a) the black line (b) the white floor
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 30. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
  25. 25.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 42. What is under the sensor? (a) the white floor (b) the black line
  26. 26.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 82. What is under the sensor? (a) the black line (b) the white floor
  27. 27.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
  28. 28.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
  29. 29.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
  30. 30.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  31. 31.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 20. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
  32. 32.🔦 A light sensor reads 30 over black and 70 over white. A good threshold is halfway between them. What is it?
  33. 33.🔦 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 white floor (b) the black line
  34. 34.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
  35. 35.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 49. What is under the sensor? (a) the black line (b) the white floor
  36. 36.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 52. What is under the sensor? (a) the white floor (b) the black line
  37. 37.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 42. What is under the sensor? (a) the black line (b) the white floor
  38. 38.🔦 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
  39. 39.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
  40. 40.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?

Answer key

  1. 35
  2. the black/white cut-off
  3. the black line
  4. 50
  5. the black line
  6. the black line
  7. neither sensor
  8. the white floor
  9. black
  10. the white floor
  11. the black line
  12. neither sensor
  13. 45
  14. neither sensor
  15. 40
  16. the black line
  17. the black line
  18. both sensors
  19. between the two sensors
  20. black soaks up light
  21. the black line
  22. 45
  23. the black line
  24. the right sensor
  25. the black line
  26. the white floor
  27. 50
  28. 65
  29. 60
  30. 55
  31. the right sensor
  32. 50
  33. the white floor
  34. 50
  35. the black line
  36. the black line
  37. the black line
  38. the black line
  39. 55
  40. 60

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