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news from the lab…
Adding an extruder fan to the Solidoodle
Categories: 3D-Printing

Trying to print PLA with the Solidoodle was a nightmare so I wanted to add a cooling fan to see if that helps anything to keep the plastic from flowing all over the place.

so I downloaded and printed (from ABS) this nice fan duct:

added a MOSFET and followed all the instructions here
but still could not get the fan running from inside Repetier.

Until today I found out by pouring over the Sanguinololu firmware that I have to actually enable the fan pin and update the firmware on the board.

In the file pins.h you have to change #define FAN_PIN -1 to

#define FAN_PIN 4

but attention, you’ll have to do it in the right section of the file, in the definition for the Sanguinolulu board, so look for

* Sanguinololu pin assignment

in there…

Fun fact, the Marlin firmware uses a very strange way of assigning pin numbers – not Atmels way of doing it, nor the physical pin numbering on the chip, but consecutive numbers for digital pins and another set of numbers for the PORTA pins (so pin 4 means actually physical pin 5 on the Atmega644, go figure!). Fortunately there’s an ascii-schematic for the Atmega644 in pins.h – just not for the Sanguinolulu…

1 Comment to “Adding an extruder fan to the Solidoodle”

  1. ndavis says:

    Thanks! I was having trouble getting it to work. After poking around with a multimeter I found that it was something on the Sanguinolu board, not my shoddy soldering skills :)

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