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Robotics Worksheet: Line Follower Light Sensors

Robotics lesson 18: Light sensors and lines · Set 139 · 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 30 over black and 80 over white. A good threshold is halfway between them. What is it?
  2. 2.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 36. What is under the sensor? (a) the black line (b) the white floor
  3. 3.⬛ A reading below the threshold means the sensor is over … (a) white (b) the sky (c) black (d) water
  4. 4.🔦 A light sensor reads 10 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 30. What is under the sensor? (a) the white floor (b) the black line
  6. 6.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 65. 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 20 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
  8. 8.⬛ The threshold of a light sensor is … (a) the top speed (b) the black/white cut-off (c) the wheel size (d) the battery size
  9. 9.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) under the right sensor (b) between the two sensors (c) far behind it (d) under the left sensor
  10. 10.⬛ Why does a light sensor read a LOW number over a black line? (a) black is wet (b) black soaks up light (c) black is loud (d) black is hot
  11. 11.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 60. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
  12. 12.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
  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 light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
  15. 15.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
  16. 16.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
  17. 17.🔦 A light sensor reads 20 over black and 60 over white. A good threshold is halfway between them. What is it?
  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 90. Which sensor is over the black line? (a) neither sensor (b) the left sensor (c) both sensors (d) the right sensor
  19. 19.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 9. What is under the sensor? (a) the black line (b) the white floor
  20. 20.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 30. Which sensor is over the black line? (a) both sensors (b) neither sensor (c) the right sensor (d) the left sensor
  21. 21.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 10. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
  22. 22.🔦 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
  23. 23.🔦 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 white floor (b) the black line
  24. 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 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
  25. 25.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 65. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the right sensor (d) the left sensor
  26. 26.🔦 A light sensor reads 20 over black and 90 over white. A good threshold is halfway between them. What is it?
  27. 27.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 40. What is under the sensor? (a) the black line (b) the white floor
  28. 28.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 25. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) neither sensor (d) the left sensor
  29. 29.🔦 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
  30. 30.🔦 A light sensor reads 30 over black and 70 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 95 and the right sensor reads 35. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
  32. 32.🔦 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
  33. 33.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 25. What is under the sensor? (a) the white floor (b) the black line
  34. 34.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 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
  35. 35.🔦 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
  36. 36.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 45. What is under the sensor? (a) the black line (b) the white floor
  37. 37.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 81. What is under the sensor? (a) the white floor (b) the black line
  38. 38.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 10. What is under the sensor? (a) the black line (b) the white floor
  39. 39.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 35. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) neither sensor (d) the right sensor
  40. 40.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 57. What is under the sensor? (a) the black line (b) the white floor

Answer key

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

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