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 80 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 33. What is under the sensor? (a) the black line (b) the white floor
- 3.🔦 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
- 4.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 90 and the right sensor reads 15. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) neither sensor (d) the left sensor
- 5.⬛ The threshold of a light sensor is … (a) the battery size (b) the wheel size (c) the black/white cut-off (d) the top speed
- 6.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 10. Which sensor is over the black line? (a) the right sensor (b) both sensors (c) neither sensor (d) the left sensor
- 7.⬛ Why does a light sensor read a LOW number over a black line? (a) black is loud (b) black is wet (c) black soaks up light (d) black is hot
- 8.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 43. What is under the sensor? (a) the white floor (b) the black line
- 9.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 40. Which sensor is over the black line? (a) both sensors (b) the left sensor (c) the right sensor (d) neither sensor
- 10.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 70. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
- 11.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 80 and the right sensor reads 15. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
- 12.🔦 A light sensor reads 10 over black and 60 over white. A good threshold is halfway between them. What is it?
- 13.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 47. What is under the sensor? (a) the black line (b) the white floor
- 14.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 15 and the right sensor reads 40. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) both sensors (d) neither sensor
- 15.🔦 A light sensor reads 10 over black and 70 over white. A good threshold is halfway between them. What is it?
- 16.🔦 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 white floor (b) the black line
- 17.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 65 and the right sensor reads 20. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
- 18.🔦 A light sensor reads 30 over black and 90 over white. A good threshold is halfway between them. What is it?
- 19.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 18. What is under the sensor? (a) the white floor (b) the black line
- 20.🔦 A light sensor reads 40 over black and 90 over white. A good threshold is halfway between them. What is it?
- 21.🔦 A light sensor reads 30 over black and 60 over white. A good threshold is halfway between them. What is it?
- 22.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 70. What is under the sensor? (a) the white floor (b) the black line
- 23.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 37. What is under the sensor? (a) the white floor (b) the black line
- 24.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 16. What is under the sensor? (a) the white floor (b) the black line
- 25.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 26. What is under the sensor? (a) the black line (b) the white floor
- 26.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 95 and the right sensor reads 40. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) neither sensor (d) the right sensor
- 27.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 43. What is under the sensor? (a) the black line (b) the white floor
- 28.⬛ A reading below the threshold means the sensor is over … (a) water (b) the sky (c) black (d) white
- 29.🔦 A light sensor reads 30 over black and 80 over white. A good threshold is halfway between them. What is it?
- 30.🔦 A light sensor reads below 50 over a black line and above 50 over the white floor. It reads 61. What is under the sensor? (a) the white floor (b) the black line
- 31.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 25 and the right sensor reads 35. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
- 32.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 20 and the right sensor reads 80. Which sensor is over the black line? (a) both sensors (b) the right sensor (c) neither sensor (d) the left sensor
- 33.🔦 A light sensor reads below 30 over a black line and above 30 over the white floor. It reads 7. What is under the sensor? (a) the white floor (b) the black line
- 34.🔦 A light sensor reads 20 over black and 70 over white. A good threshold is halfway between them. What is it?
- 35.🔦 A light sensor reads below 40 over a black line and above 40 over the white floor. It reads 58. What is under the sensor? (a) the black line (b) the white floor
- 36.🔦 A light sensor reads below 60 over a black line and above 60 over the white floor. It reads 46. What is under the sensor? (a) the white floor (b) the black line
- 37.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 85 and the right sensor reads 40. Which sensor is over the black line? (a) neither sensor (b) the right sensor (c) the left sensor (d) both sensors
- 38.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 40 and the right sensor reads 15. Which sensor is over the black line? (a) the left sensor (b) both sensors (c) the right sensor (d) neither sensor
- 39.🔦 A light sensor reads 20 over black and 80 over white. A good threshold is halfway between them. What is it?
- 40.🔦 A robot has a left and a right light sensor. Below 50 means black. The left sensor reads 75 and the right sensor reads 75. Which sensor is over the black line? (a) the right sensor (b) the left sensor (c) neither sensor (d) both sensors
Answer key
- 45
- the white floor
- the white floor
- the right sensor
- the black/white cut-off
- the right sensor
- black soaks up light
- the white floor
- the right sensor
- neither sensor
- the right sensor
- 35
- the black line
- both sensors
- 40
- the white floor
- the right sensor
- 60
- the black line
- 65
- 45
- the white floor
- the black line
- the black line
- the black line
- the right sensor
- the black line
- black
- 55
- the white floor
- both sensors
- the left sensor
- the black line
- 45
- the white floor
- the black line
- the right sensor
- both sensors
- 50
- neither sensor
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