Well how 'bout that, it sorta works. I don't know if I am going to kit this one or just have fun with it, but either way, here it is.
I still need to finish the lift mechanism for the pen, but other than that, 100% solid. Woo Hoo!
so are cheap steppers from lmr shop
Also how do you plant to lift the pen?
i like the idea of using steppers. would make a great desk bot not to fast .might be a good platform for mapping robots as well as drawing ,good stuff
No, I usually stick with Ebay. I saved a couple bucks over the "LMR shop" as well. In terms of the pen, I started with a parallelogram set-up and servo to lift it, but I was getting too much slop out of the pivots and thus, went with the pencil in a tube system. In terms of the new lift, I think something as simple as just a collar around the pencil and just an extended arm of the servo. --Gotta KISS.
Really nice and tidy turtlebot loving the use of the nano under shield. Maybe use an electromagnet to lift the pen up when switched on and drops pen down when switched off, or viceversa with a spring..
I know this is an older project. But would you have the code available to post. I am curious how you controlled the 2 stepper motors.
I used the "Stepper" example included with the Arduino IDE. The only change is that these little $5 steppers require two pins to be swapped. The example is: Stepper myStepper(stepsPerRevolution, 8,9,10,11);
It should be: Stepper myStepper(stepsPerRevolution, 8,10,9,11);
Other than that, it was just a matter of trial and error to determine how many "clicks" = how far traveled and how many clicks = 360 degree spin. After that, it was just the Arduino "map" function to convert these numbers to what I needed for each move. That's it!