Monday, September 8, 2014

Project 3D Printer - Oh No!!! I released the magic smoke from Arduino Mega and Pololu

Made a lot of progress Saturday on my 3D Printer build. Sunday I focused on configuring the Marlin firmware on the Arduino Mega and getting all the electronic components working correctly:
  • verifying that each axis getting power
  • dialing in current settings on the stepper drivers
  • making sure that stepper directions are set correctly
  • hot end and temp sensor working correctly
I tested using Pronterface (this was my first time using it, checked tutorials later but learned nothing new – the interface is very understandable).
  • able to move x and z axis
    • x-axis moves in opposite direction
      • Inverted the movement direction for x axis in Marlin firmware and now it moves in correct direction
    • z-axis moves but not well
      • increased current to steppers using trim-pot on Pololu board to max current (I did try decreasing also but no movement at all at lower current) and it moves more reliably
  • no movement on y-axis
    • doesn't seem to be getting any voltage – can turn motor with no resistance, even when sending moves in opposite direction.
  • Extruder moves when stepper driver is set at max current but with very little force (light pressure from 1 finger stops rotation)
My main goal Sunday to figure out why the Y-axis is not moving/ getting power. I tried connecting the Y axis motor to the X axis controller (using the original Y axis wiring) and the motor works. Testing the Y axis controller with other stepper motors resulted in no movement. Switching out driver boards – still no movement on Y axis.

To get a cleaner test I removed all wires/plugs/boards from the RAMPS board (including the Arduino Mega) and carefully re-connected everything (or so I thought).  Once I was done re-assembling everything I switched on power to the board and... POOF the x-axis stepper board let out smoke and my computer shut  down.  I instantly cut the power off but I was to late.  On close inspection of the stepper driver board I saw that I had plugged it in incorrectly (2 pins were hanging off the end).  It turns out that not only did I kill the stepper board I also rendered the Mega useless because the USB-to-serial converter on the board got fried, so I can power the board but serial communication is essentially gone.

I guess I've earned another one of these badges http://www.adafruit.com/products/565

I ordered a new Mega board and another RAMPS board (just to be safe since I can't test the one I have).  I think I need a higher voltage PSU to power the stepper motors that I have (minimum voltage for them is 12V) but the  good news is that since I am not using a heated bed my total power requirements are lower that I thought.