add 8 motors

How do I add 8 more stepper motor controllers to the ramps1.4? How do I control the motors? I want to add 8 more extruders.

I don't have any experience with RAMPS but what are you trying to do? Maybe there is a mechanical solution. Are all the extruders independent or slaved to each other?

use different colors, one at a time.

Okay, I don't know how to do this but I know it can be done. You will need to have someone else fill in the details. You technically are only driving one of your extruder steppers at a time. Theoretically you can use one driver to run as many different steppers as you want as long as they don't need to operate at the same time. It is called multiplexing if you want to google for more help.

Good luck.

richrap did this with three extruders - see details here. He ran the same stepper channel to three different stepper drivers and controlled their enable lines individually.

Simba is working on a 10 motor design, but it may not be ready yet...

If you're ok with really low-tech, you could get four 1-pole 8-position rotary switches (one switch for each output wire of the stepper driver). That way you would only need 1 stepper driver.

MattMoses Wrote:
>
> If you're ok with really low-tech, you could get
> four 1-pole 8-position rotary switches (one switch
> for each output wire of the stepper driver). That
> way you would only need 1 stepper driver.

Not a good idea, disconnecting and connecting stepper motors to a driver under power will damage the driver.

> Not a good idea, disconnecting and connecting stepper motors to a driver under power will damage the driver.

For something low power like a Pololu driver it probably doesn't matter that much. I have hot-swapped stepper motors by simple "plugging and unplugging" and the Pololu drivers don't seem to care... But you're right that it is not good practice.

If you're worried about it, you can simply disable the motor driver before turning the switches. In most printer communication programs this just takes a click of a button.

It looks like there is nothing available yet. I have some ideas but I need a good readable RAMPS 1.4 schematic. I have found several schematics that are small and do not take well blowing up to print. Any links anybody? The other issue is software. I thought the mega 2560 is looking for a sketch not a c++ program. What is the actual program the mega2560 is running? Where can I find the source? Is there a color definition standard for 3D? I am thinking to use the Opengl RGB definition to send to the printer.

The RAMPS 1.4 wiki page should have all the schematics you need.

The actual program the mega2560 is running is called "firmware". There are many kinds. Here's a big list of firmwares. Many people use Marlin, you can get the Marlin source here.

I don't think there is a "standard" for color in 3D models. Some commercial printers use VRML for color, see here for example. The AMF standard supports color, but I don't know of any software (either modeling or slicing) that currently supports it.

As far as I know, none of the hobby level slicers or firmware actually interprets true RGB color information in the 3D models. The multi-color models you see on thingiverse are typically done by printing two disjoint, interleaved solids - one for each color. Richrap's beautiful multicolor prints are done by switching manually between extruders or coloring the filament with dye.

If anyone out there has better information on this, please correct me .

It looks like you will be charting some new ground, gwbcomm...

8 extruders is a lot! That implies total of 11 stepper drivers. I don't think anyone goes up to 11 yet

The RepRapPro use a slave board to provide more extruders, that might be a general way to do it. Certainly you could chain RAMPS board to get 10 drivers, some work would be needed in firmware.

Depending on how many extruders need to be active at the same time, I don't know how feasible it is to multiplex several motors on to one stepper driver. I think switching inductive loads is always going to be ugly, voltage spikes are good at killing electronics.

The other solution is cheaper drivers, but manufacturers are generally adding features rather than cutting prices. I did look at creating stepper drivers from some cheap MOSFETs and a PIC or similar to drive them, but getting expected features like current control and microstepping would take a lot of development effort.