enter image description hereenter image description hereMy team created a simple program to drive robot out. It consists of a MyBlock to drive straight a specified distance and speed utilizing the Gyro sensor. The program then activates a third large motor to actuate the green large motor block to rotate the motor 45 degrees to activate one of the missions. On the drive out (MyBlock), the large motor also starts running at the same time instead of sequentially. Can anyone help me figure out why this occurred? Drive motors were plugged into B+C, and Large Motor was plugged into A.

The first picture is just the three blocks. The little fuzzy interference pattern indicating which block was active (when it glitches) was on both the MyBlock and the Large Motor Green block. This was confirmed because the robot was still driving out and the arm started rotating.

  • 2
    Can you share a screenshot of the program? Apr 12, 2022 at 1:27
  • I will try, but the glitch isn't consistent.
    – John
    Apr 12, 2022 at 15:53
  • I have a screenshot, but not sure how to share it in a post. It's not allowing me to paste the picture, and I don't see a way to attach it.
    – John
    Apr 14, 2022 at 15:05
  • 1
    If you edit the question, there is an "image" icon you can click on to add the image. Apr 15, 2022 at 15:45

2 Answers 2


The final block in the sequence is telling motor D to rotate 1 revolution at 75% power.

In the description of the problem, it says "and Large Motor was plugged into A."

Any chance that is the bug? Put the wire in D instead of A, or change the last block in the program from "D" to "A".

  • Good catch. Actually, the offending program was changed and I tried, unsuccessfully, to recreate it. Still wouldn't explain in my mind why two sequential blocks were going off concurrently.
    – John
    Apr 16, 2022 at 20:05
  • I was able to duplicate the condition again and captured it on camera. The video shows the robot moving out and simultaneously lowering an arm which it shouldn't do until it was done moving out.
    – John
    May 9, 2022 at 20:59

Inside of the loop, the motor block tells motors B+C to start and keep running forever.

screenshot of motor "on" block

However, there is no block that tells motors B+C to stop, so they keep on running even after the loop ends. Adding a block to stop the motor after the loop ends should get the desired behavior.

screenshot of motor "off" block

  • When the motor is inside a loop, it runs for 25 ms or so and then proceeds to next block, so you don't have to stop the block manually. And, it doesn't always do this. In fact, I changed the cord from the "A" motor and the incident hasn't yet repeated. Not sure how a cord could cause such a problem.
    – John
    Apr 19, 2022 at 14:29

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