-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 8/29/2012 11:49 AM, Lars Segerlund wrote: > What I was thinking is do the kinematics on the PC and just dump > positions per axis on the avr ..... point in time and space so to > speak .... it should work to stream to it ... > > I mean it's an open loop system ?
Yes, it's an open loop system, driving step/dir stepper motor controllers that have no feedback (ie: missed steps ruin your print). There are folks doing the math on the PC. The bottleneck then becomes the serial communications link to the AVR, so there is work in progress to support g-code files with some form of binary compression so the thousands of little line segments can be sent quicker. The Arduino *IS* connected via USB, but there is an actual serial link running at apx. 1 MBit/s or so on the AVR that limits the ultimate speed: Google Groups thread about hacking compressed G-code for Rostock: https://groups.google.com/forum/?fromgroups=#!topic/deltabot/NI9WrN1Vmio IMHO getting LinuxCNC to do the math *AND* drive the steppers seems like a much better overall solution. I realize some hardware would be required, but folks in the RepRap world are already buying hardware, with a pretty typical setup listed below. Note that the designs are open source and there is enough volume in these parts that the Chinese are direct selling through e-Bay and drop-shipping straight from the orient: Arduino AVR controller board: $25-80 http://www.ebay.com/itm/Arduino-MEGA2560-ATmega-8U2-ATMEGA2560-16AU-USB-Cable-/270970778895?pt=LH_DefaultDomain_0&hash=item3f171df50f RAMPS 'shield' board to interface the Arduino to the printer: $50-80 http://www.ebay.com/itm/RAMPS-1-4-electronics-SD-RAMPS-and-cables-RepRap-3D-printer-/170902524785?pt=LH_DefaultDomain_0&hash=item27ca959371 Qty 4-5 Polulu stepper motor drivers: $10-15/ea http://www.ebay.com/itm/4-x-A4988-stepper-driver-pololu-compatible-3D-printer-reprap-prusa-mendel-/150871293385?pt=LH_DefaultDomain_2&hash=item2320a13dc9 Note: First price is Chinese e-bay, second price is US/EU sourced. A LinuxCNC based solution would still need the stepper motor drivers, but that leaves $75-$150 to create an interface board to connect a parallel port to some thermistors and high-current 12V FET switches (all of which except for the A/D converters is on the RAMPS board). - -- Charles Steinkuehler [email protected] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlA+Z/UACgkQLywbqEHdNFxYhgCgi11q9jrSQM6l+j4BXFhqkyKL RwYAoJ1NJvclSCVdEby5WtT3EtRFugsY =XxQk -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
