thinking of digging into 3D printing, can i just add a head to my CNC router?

andypugh wrote:

Of course, if you want a _real_ project then you could write a driver for the MAX38155 using the Mesa BSPI module.....

I think that is this, right?

github.com/sleepybishop/linuxcnc/blob/fi...s/max31855_bspi.comp

if you have an arduino and a mesa card, you mgiht be able to do what the mojov3 FPGA board does, its a spartan6 with onboard arduino, and someone has written a comp to use the arduino analog pins as an adc

github.com/LinuxCNC/linuxcnc/compare/mas...op:fishybearG-master
load all the commits, its kinda buried

here is my post from the one thread about 3doprinter configs, and what i found reguarding other people using mesa cards for 3dp

forum.linuxcnc.org/additive-manufacturin...nfigs-comps-examples

Something i thought of, if i am running BSPI to my MAX31855 modules, my bed heater thermocouple will be fine, but my head thermocouple will be about 10feet (Mesa to machine cable) + about another 10feet through the two 56" cable drag chains on the Y and X axis. the top of the X axis just rides up and down with the Z axis, so no extra chain for the Z rise and fall.

but 20 feet of wire is a bit much for SPI... so i thought, RS-485 can run the same voltage over longer distance. so why not use a pair of RS-485 transceivers, one for clock, and one for data return (no data is sent to the MAX31855), and the chip-select pin can be a single wire. it will take twice the wires, but i can run a cat5e cable for the twisted-pair for the RS-485 differential signal, and use the 3rd and 4th pairs for power and ground for the transceivers and the MAX31855 at the far end.

only question i have, how do i find the BSPI pins on my Mesa7i80HD-16? the dmesg method doesn't seem to work for me. though if i botch the configs and cause LinuxCNC to error, it shows the Mesa pin config, but no BSPI pins are shown. if i change:to be:and do the same (cause a botched config to generate an error), will it then show the BSPI pins? or am i supposed to selet what pins are used?

~Travis

working with an arduino and a .comp file (compiled and installed) to control my master power, other than the 5V buss powering the Mesa 7i80 and the arduino.
.comp file here: github.com/travis-farmer/linuxcnc/blob/master/serialcon.comp
arduino sketch here: github.com/travis-farmer/linuxcnc/blob/m...ialcon/serialcon.ino
hal config that uses it:everything loads and compiles without errors, even the .comp via halcompile.
yet nothing is sent to the Arduino, and nothing is received from the arduino. i have confirmed the serial port dev is correct, so as i am somewhat new territory, writing .comp code, i am unsure where my error would be. anybody have any thoughts? questions? the arduino and .comp will be used to control master power for my machine, and report back power bus volts.

~Travis

got it
well, partly... i needed HAL to send a signal to the Arduino to let it know it is alive, and if the arduino doesn't get the signal for over 5 seconds, it powers down the power supplies.
so, 5V will come from an old ATX power supply via +5v-StandBy, which is just enough current for the Mesa card and the Arduino. 12v will come from the ATX +12v bus. 24v will come from the ATX +12v bus, by way of a step-up dc-to-dc converter (low current on 24v). the stepper voltage will be powered on by a 12v relay, powered by the ATX +12v turning on. it will be an independent switch mode power supply. currently 36v, but thinking of stepping up to 40v or so.

so that is planned out (not solved until it is in action). really it is overly complicated. a future revision will simply take an input signal from the Mesa card to signal when to power on. E-STOP off, likely. so i need a pin to go high when E-Stop is off, and to confirm, another pin to go low from the same signal. this way, if both are low, or high, then power off (incorrect signals) when the signals are correct, power on. i could use a charge-pump... but all my stepGen signals are in use, currently... can i bitbang a charge-pump on any pin? probably with a custom .comp file... i could just turn a pin on and off at a certain rate, faster than N seconds. then the arduino checks for a change at least every N seconds... seems pretty easy to figure out... solved that

~Travis

github.com/travis-farmer/linuxcnc/blob/m...rge_pump.compexample of use in HAL:it is a little quick and dirty, but hey, if anybody needs a BitBanged Charge Pump with diffrential output. and you can set the rough speed by altering the timer delay, currently ~250ms.
i hope somebody else finds a use for it as well.

now i just have to design the Arduino end, and be done with it, so i can get back to my 3D printer planning.

~Travis

1. The goal is to adapt a 3-5 Axis Machine Frame, LinuxCNC & MESA Controller to the job of 3D Printing. 

A1. LinuxCNC & MESA are not Tailored to 3D Printing which is not included in PNCConf.  For 3D Printing with LCNC & MESA, one could attempt the HAL as formated in this post or similar to obtain the appropriate result.

HM2 HAL for 3D Printing: 
Minimum Requirments: 

1. Controller Temperature: 
   1. Analog Thermistors
   2. Heat Controller
2. Controller Extrusion: 
   1. Steppers