1. Motors and Sound Troubleshooting Tips

2. © 2005 4H-CCS Problem 1 Why can’t I download my program to the RCX?

3. © 2005 4H-CCS Solution 1 The RCX was facing the wrong direction. (Don’t forget to turn it on too!) InfraRed receiver must face IR Tower

4. © 2005 4H-CCS Problem 2 Why won’t the motor work?

5. © 2005 4H-CCS Solution 2 It was connected to a sensor port. Motor ports are A, B, and C. Sensor ports Motor ports

6. © 2005 4H-CCS Problem 3 What is wrong with this program?

7. © 2005 4H-CCS Solution 3 Bad wiring. Always check for bad wires. Bad wire Missing wire

8. © 2005 4H-CCS Problem 4 This program is supposed to turn on Motor A for 4 seconds, then turn off the motor. What’s wrong?

9. © 2005 4H-CCS Solution 4 There was no “Stop Motor” icon.

10. Wiring Tips and Troubleshooting

11. © 2005 4H-CCS Many of the problems associated with programming in Robolab have to do with mistakes in wiring the Icons or Modifiers.

12. © 2005 4H-CCS Problem 5 This Program looks good at first glance, but notice the broken black arrow on the upper left hand corner of the screen. If you click on the arrow, you will see the list of errors

13. © 2005 4H-CCS Solution 5 The List of Errors shows that neither the input nor the output of the ‘Wait For 4 Seconds’ Icon are wired. It looks like the programmer just laid the icon over the wire. If you grab the icon and drag it down, you can see this clearly.

14. © 2005 4H-CCS

15. Problem 6 This Program looks just like the previous one, and again notice the broken black arrow on the upper left hand corner of the screen. If you click on the arrow, you will see a different list of errors.

16. © 2005 4H-CCS Solution 6 This time, there’s only one error listed. It says that the end of the ‘Stop All Outputs’ Icon isn’t wired. If you’re in the ‘Select’ mode of the tools palette (that’s the arrow) and highlight the wire connected to the Red Light, you’ll see a ghost image of the wire connected from the input of the Stop Sign to the input of the red light.

17. © 2005 4H-CCS

18. Problem 7

19. © 2005 4H-CCS The List of Errors tells us that the ‘Motor C Forward’ Icon isn’t wired. But when we click on one of the errors, neither corner of the ‘Motor C Forward’ Icon flash. And, when we look at the icon, we can see that it is correctly wired……hmm!

20. © 2005 4H-CCS Solution 7 What happened here is that our programmer took the icon off the palette by mistake and rather than delete it, he tried to put it back on the palette. In trying this, all he did was hide the icon under the palette. Delete this icon and the arrow will turn white.

21. © 2005 4H-CCS Problem 8 The robot is supposed to go forward for 4 second but it stops after only 1. What could be wrong?

22. © 2005 4H-CCS Problem 8 Someone forgot to wire the modifier to the ‘Wait for Time’ Icon. Every icon that can have a modifier has a “Default Value.” The default value for the ‘Wait for Time’ icon is 1 second.

23. Modifiers, Loops and Jumps Troubleshooting Tips

24. © 2005 4H-CCS Problem 9 Write a program that plays a beep three times in a row. This plays sound #3, NOT 3 sounds.

25. © 2005 4H-CCS Solution(s) 9 Use 3 Play Sound icons, or use a loop that loops 3 times.

26. © 2005 4H-CCS Problem 10 Turn on motor A at power level 1. This is a numeric constant modifier NOT a power level modifier. (Strangely enough, it does not show a bad wire. Hmmmm…..)

27. © 2005 4H-CCS Solution 10 Use a Power Level 1 modifier.

28. © 2005 4H-CCS Problem 11 Write a program that beeps forever. What’s wrong? This is a yellow jumpBut this is a red land

29. © 2005 4H-CCS Solution 11 Make sure jump and land pairs are the same color.

30. © 2005 4H-CCS Problem 12 Write a program that beeps forever. What’s wrong now? Start Jump to green land Land hereEnd Oops!

31. © 2005 4H-CCS Solution 12 Be careful not to mix up the order of your jumps and lands!

32. Sensor Wait-for’s Troubleshooting Tips

33. © 2005 4H-CCS Problem 13 Why won’t the light sensor work? This is a motor port.

34. © 2005 4H-CCS Solution 13 Sensors need to be connected to sensor ports 1, 2 or 3. Sensor ports

35. © 2005 4H-CCS Problem 14 What’s wrong with this set up? The touch sensor is connected to port 1. But the software says the touch sensor is on port 3.

36. © 2005 4H-CCS Solution 14 Connect the touch sensor to port 3. Or, change the port number in the software.

37. © 2005 4H-CCS Problem 15 Why won’t the touch sensor work?

38. © 2005 4H-CCS Solution 15 Make sure the cable is connected to the front of the touch sensor. WRONGRIGHT

39. © 2005 4H-CCS Problem 16 What isn’t too great about the way the light sensor is mounted?

40. © 2005 4H-CCS Solution 16 If the light sensor is too high, it has a harder time distinguishing between dark and light. Mounting it lower to the ground will help.

41. © 2005 4H-CCS Problem 17 What’s wrong with this program? What is the default port?

42. © 2005 4H-CCS Solution 17 Remember: Different sensors MUST be on different ports in the software. If a port is not specified, it assumes Port 1.

43. © 2005 4H-CCS Problem 18 This program should turn on motor A until the rotational sensor has turned 2 revolutions, then turn off the motor. Why doesn’t it work? Hint: What is the default number of ticks in a Wait-for Rotation icon?

44. © 2005 4H-CCS Solution 18 The default number of ticks is 16, or 1 revolution. For 2 revolutions, you must specify the number of ticks with a numeric constant modifier. 32 ticks = 2 revolutions

45. Conditional Statements Troubleshooting Tips

46. © 2005 4H-CCS Problem 19 What’s wrong with this program?

47. © 2005 4H-CCS Solution 19 Remember: All forks need a fork merge.

48. © 2005 4H-CCS Problem 20 This program is supposed to turn on motor A if the touch sensor is pressed, otherwise turn on motor C. What’s wrong?

49. © 2005 4H-CCS Solution 20 The branches of the fork are mixed up. This is a common mistake.

50. © 2005 4H-CCS Problem 21 In this program, if the light sensor reads a value above 80, it should turn on motor B. Otherwise, it should beep. Why doesn’t it work? Hint: What is the default light level value?

51. © 2005 4H-CCS Solution 21 The default light level value is 55. To specify a different value, you must use a numeric constant modifier.

52. © 2005 4H-CCS Problem 22 What’s missing from this program?

53. © 2005 4H-CCS Solution 22 Before every rotational sensor fork, you must reset the rotational sensor. Rotational sensor reset

54. Multiple Tasks & Timers Troubleshooting Tips

55. © 2005 4H-CCS Problem 23 What’s wrong with this program?

56. © 2005 4H-CCS Solution 23 Remember: Only forks need a fork merge. Task splits need red stop lights at the end of each task.

57. © 2005 4H-CCS Problem 24 What’s wrong with this program? Hint: What do all forks need?

58. © 2005 4H-CCS Solution 24 Unfortunately, if you use a task split after a fork, there is NO WAY to merge the fork back together, so just don’t do it.

59. © 2005 4H-CCS Problem 25 This program should beep for exactly 5 seconds, but it beeps forever! What’s wrong? Hint: What do you do immediately after you land on the Red Land?

60. © 2005 4H-CCS Solution 25 The problem is, the timer was being reset back to 0 every time you landed. In this program, the timer is reset only once at the beginning of the program.

61. Containers Troubleshooting Tips

62. © 2005 4H-CCS Problem 26 This program wants to use the value of the red container, which is 22, in the light sensor fork. What’s wrong?

63. © 2005 4H-CCS Solution 26 The number 22 was stored in the red container, but the light sensor fork was using the value of the yellow container.

64. © 2005 4H-CCS Problem 27 Why is there a bad wire in this program? bad wire

65. © 2005 4H-CCS Solution 27 Remember, forks and loops need to use the value of the container (modifier with white background). container value

66. © 2005 4H-CCS Problem 28 Why is there a bad wire in this program? bad wire

67. © 2005 4H-CCS Solution 28 To store a sensor value in a container, you must use the sensor port’s value. sensor port value