15 October 2011

SumPods Have Landed and Dancing Motors

I spoke with Richard earlier this evening and he confirmed other SumPods had been released into the wild.  This can only be a good thing, with eager owners now (feverishly? God I've got to get out more!) building their new 3D printers and Richard getting the feedback he desires.

Me, I'm still waiting for a print bed part to arrive. I noticed at the beginning of the week when I started assembling the SumPod MDF parts that something was missing.  I'll proceed with the mechanical build when the missing part arrives - it should have turned up two days ago checking with Richard.  Richard isn't the only one suffering from delays - hurry up Royal Mail!  Rather than sit on my hands or write  more of my thesis (God I hate thesis writing and this blog provides some light relief), I soldered up a few more bits of the SumPod and coaxed a few of the stepper motors into life.  The following short video shows my progress.

It may not seem much, but to me it's significant, the equivalent of getting a LED to flash at the right frequency on a newly designed board.  It proves the software toolchain and hardware are working.  For the SumPod it means I've correctly soldered the RAMPS board; downloaded the complete Sprinter firmware from GitHub, modified it to work with the RAMPS hardware and uploaded it to the Arduino Mega 1280 board; soldered up the steppers correctly and got ReplicatorG working.  Phew!

The following steps describe how you could replicate this experiment to check your software and hardware setup:

Stepper motors connections are as follows (taken from here)

Zapp Automation / SY42STH47-1684B

Stepper motor datasheet

Pololu PinColour
I used some of the leftover socket headers from the RAMPS build, soldered to the stepper motor leads to connect to the RAMPS board.  I'll post later the updates I've made to the RAMPS board.

Plug the Arduino board to a computer using the supplied USB cable. Now for the software.
  1. Download the Arduino software
  2. Download the Sprinter firmware I've selected this because it has built in support for printing from an SD card.
  3. Extract the Sprinter firmware into the hardware folder of the Arduino software directory.
  4. Open the Sprinter.pde file using the Arduino IDE and edit configuration.h for the correct board #define MOTHERBOARD 33 
  5. Now edit the pins.h firmware file, changing the X_MIN_PIN, Y_MIN_PIN, Z_MIN_PIN to -1 (to disable them otherwise your steppers will only go in one direction during your test) in the MOTHERBOARD == 33 section.
  6. Click verify in the Arduino IDE to recompile the firmware.  You shouldn't get any errors and the updated firmware can be uploaded ready for the next stage.
  7. Download ReplicatorG
  8. Run the ReplicatorG and connect to the board.  Select the correct serial port and Klimetkip (115200 baud) Drive under the main Machine menu.
  9. Now click the Control Panel button after connecting and you should be able to replicate the little stepper motor dance from the video.
SumPod Guinea Pig signing off


  1. Be sure to select from the Arduino IDE menu "Tools > Board > Arduino MEGA" or you will get compile errors...

  2. Have you considered using Marlin instead of Sprinter? It's said to be a lot faster and smoother in printing due to its linear acceleration and look ahead (to keep speed) functions. And it still supports printing directly from SD cards as it derives from Sprinter. As I don't own a Printer yet, I couldn't try it...so it's more an advice out of the blue, but might be worth a try.

  3. Hi Andy,
    I'll certainly give it a try, I started with Sprinter upon Richards suggestion - I'm still waiting for the SumPod tailored version of Sprinter. I'm just back from my holiday and when I get a chance I'll investigate your suggestion.

  4. when trying this make sure to not set the output current of the pololu A4983 Stepper Motor Driver Carrier too high, otherwise your drivers may smoke up. just nearly happened to me...
    should richard have provided heatsinks like officially recommended?

    1. I can supply heatsinks cheaply if needed. I fully intend to heatsink my stepper drivers.

  5. Fixer, do you have a recommended way of setting the output current? i just reduced the current (turn pot counterclockwise) will the motos's constant "whining" stopped

    and thanks for the blog btw, it's really really helpful

    1. Set the pot to a third from minimum initially and adjust from there. Minimum is fully counter clockwise and be careful the pots are fragile.