-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 So I finally cobbled together enough pieces to glue LinuxCNC to my 3D printer and get a print. Figured I'd share in case anyone else reading this list is as crazy as I am. :)
Photos: https://plus.google.com/photos/106079792142766516843/albums/5802703397921008689 Video: http://www.youtube.com/watch?v=DqnAU1g5Rys The first print (in the video) failed because I don't have the bed heater working yet, so I added some blue tape and printed again successfully (photos). Details: Motor control is via straight-forward connection of parallel port pins to the appropriate step/dir pins on RAMPS, although VCC on the RAMPS is tied to 3.3V instead of 5V to insure the A4988 stepper drivers recognize the 3.3V parallel port logic levels. The extruder heater is implemented using an open-collector inverter on one of the parallel port lines to provide 12V swing instead of the 3.3V my parallel port drives. The resulting 12V signal is used to control the stock FET on the RAMPS board. The extruder temperature is sensed with the existing RAMPS thermistor circuit (running on 3.3V VCC), using an I2C A/D converter on my interface board. The I2C interface is implemented using two output pins and one input pin. The SDA output pin is inverted and drives an open collector inverter to allow bidirectional communication. I wrote a custom HAL module to bit-bang an I2C interface to the ADC using the existing parallel port driver, and another one to turn the raw ADC readings into degrees Centigrade. Add a comparator HAL module to serve as a bang-bang thermostat control, and it's time to print! Oh...and everything is running under a stock Debian system using the preempt-rt patched version of LinuxCNC (not required...the Ubuntu version with a custom RTAI kernel will work just fine too). I'll post the code and more details as I get time, probably on the RepRap wiki. The ultimate goal of all this is to make a delta-arm 3D printer and use kinematics in LinuxCNC for the tricky math bits that are hard to do on the AVR micro-controllers most 3D printers use for control. - -- Charles Steinkuehler char...@steinkuehler.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlCHYq8ACgkQLywbqEHdNFwG9wCgvmSbm4fN5e0KtGRSfXqgPZrm 2EoAoKwOGIVqSaopPwJE2wWzDpziajaK =3yWP -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
