mCar not drawing right

#1

Hi All;

I hope all is well.

Working on getting mCar going.

  • It’s all assembled correctly, check.
  • Software updated / latest version.
  • Got it moving and drawing, but the images don’t come out right.
  • I checked and adjusted the torque on the stepper motor, etc.

Attached is a drawing of what were supposed to be two squares as the test image, a small and larger square… no luck. I get a strange triangle drawings.

20170828_073619[1].jpg1008x1814 386 KB

Looked in the forums / online support pages, could find anything.

Any ideas on how to fix ?

#2

Hi kekolalada,

First, please make sure the wiring connection is correct refer to pictures below:

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Secondly, The Microstep should be set to HHH (pull the small white switches on each motor driver to H side). And make sure the order for the color wires from each stepper motor is correct.

Thirdly, check the settings on the mDraw software, make sure you set the correct directions for both motor A and motor B.

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#3

Hi, Thank you for the detailed response. Much respect. I reviewed all of the above, and re-checked on the mCar (aka… Peezu) . All was correct. I started messing around with the servo motors and adjusting the gain screws on each side. After some lengthy trial and error, was able to draw a square ! whoo hoo ! I will keep working on it to dial in the resolution, but I think we good to go. Thx again. Check out the attached.

20170831_082730[1].jpg2580x1451 890 KB

#4

Very interested in your stepper motor robot. I didn’t know that Makeblock was selling these. I am developing a less-elegant version of this robot, using an mbot arduino board and a couple of very inexpensive stepper motors. I have modified the mbot code so that it uses I2C to activate a small arduino board (arduino mini pro) and a Darlington transistor chip that drives the motors. How does your robot do the drawing on paper? I drilled a hole in the base of the robot (which I made of plastic) and the user simply inserts a marking pen into the hole. Works pretty well. In your drawings, I notice that small arcs are drawn at the turns. I had the same problem - solved by making sure the pen is exactly halfway between the wheels and directly in line with them. Is there a way of adjusting that on the mCar? Are you using this for teaching purposes? I am and I’d be happy to share ideas with you. Best, Eric

#5

Hi Eric; The way I was able to get it to work, was via the gain control on the motors and a lot trial and error figuring out what settings to use. On the arcs, I could not get it to solve this issue, but maybe by some more tinkering, I may. No, the project is more for my own use in learning about robotic. I hope yours works !

#6