Robotics Worksheet: Line Follower Light Sensors
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.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
- 2.🔦 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
- 3.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 85. Which sensor is over the black line? (a) the left sensor (b) the right sensor (c) both sensors (d) neither sensor
- 4.⬛ The threshold of a light sensor is … (a) the wheel size (b) the black/white cut-off (c) the battery size (d) the top speed
- 5.🔦 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
- 6.🔦 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
- 7.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 80. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
- 8.⬛ In a two-sensor line follower, both sensors see white. Where is the line? (a) far behind it (b) under the left sensor (c) under the right sensor (d) between the two sensors
- 9.⬛ Why does a light sensor read a LOW number over a black line? (a) black is loud (b) black is wet (c) black is hot (d) black soaks up light
- 10.🔦 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
- 11.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 55. What is under the sensor? (a) the black line (b) the white floor
- 12.🔦 A light sensor reads 10 over black and 90 over white. A good threshold is halfway between them. What is it?
- 13.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
- 14.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 47. What is under the sensor? (a) the black line (b) the white floor
- 15.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 56. What is under the sensor? (a) the white floor (b) the black line
- 16.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 70 and the right sensor reads 25. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) the left sensor (d) neither sensor
- 17.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 30 and the right sensor reads 60. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) the left sensor (d) both sensors
- 18.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 8. What is under the sensor? (a) the white floor (b) the black line
- 19.🔦 A light sensor reads 40 over black and 70 over white. A good threshold is halfway between them. What is it?
- 20.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 70. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
- 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 10. Which sensor is over the black line? (a) the right sensor (b) neither sensor (c) both sensors (d) the left sensor
- 22.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
- 23.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 5. What is under the sensor? (a) the white floor (b) the black line
- 24.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
- 25.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 21. What is under the sensor? (a) the white floor (b) the black line
- 26.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
- 27.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 68. What is under the sensor? (a) the black line (b) the white floor
- 28.🔦 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 black line (b) the white floor
- 29.⬛ A reading below the threshold means the sensor is over … (a) white (b) black (c) the sky (d) water
- 30.🔦 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 white floor (b) the black line
- 31.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
- 32.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 57. What is under the sensor? (a) the black line (b) the white floor
- 33.🔦 A light sensor reads 40 over black and 60 over white. A good threshold is halfway between them. What is it?
- 34.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 33. What is under the sensor? (a) the white floor (b) the black line
- 35.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 60. Which sensor is over the black line? (a) neither sensor (b) both sensors (c) the left sensor (d) the right sensor
- 36.🔦 A light sensor reads 40 over black and 80 over white. A good threshold is halfway between them. What is it?
- 37.🔦 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
- 38.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 26. What is under the sensor? (a) the black line (b) the white floor
- 39.🔦 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 white floor (b) the black line
- 40.🔦 A light sensor reads 10 over black and 80 over white. A good threshold is halfway between them. What is it?
Answer key
- 40
- the white floor
- neither sensor
- the black/white cut-off
- the white floor
- the white floor
- neither sensor
- between the two sensors
- black soaks up light
- the black line
- the white floor
- 50
- 35
- the white floor
- the white floor
- the right sensor
- the left sensor
- the black line
- 55
- neither sensor
- the right sensor
- 45
- the black line
- both sensors
- the black line
- 65
- the white floor
- the white floor
- black
- the black line
- 50
- the black line
- 50
- the white floor
- neither sensor
- 60
- the white floor
- the black line
- the white floor
- 45
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