Ramps 1.4 with 6 stepper motors

[yeoyeo]

Hello,
I’m fairly new to Arduino but I am working on a project where I have to control at the minimum 5 motors independently along with a solenoid and possibly a 6th motor.

My project runs 3 axis similar to a 3d printer but I need a few extra motors and solenoids for another operation (like a large pick and place machine).

I was going to order a ramps 1.4 since I could control 5 motors and there seem to be tutorials posted online.

Here are some of the questions I have after looking at some diagrams and reading some posts:

1a. Is 6 stepper motor control possible with the ramps? The first two diagrams attached below have 2 motors connected to the z axis driver.

I believe these are connected in parallel (I’m not sure what the board I have circled in red is for in the second picture).

Since they are both connected in to one driver, I’m assuming they both run at the same time + in the same direction etc?

Is there anyway I can run these independently?

1b. I’ve seen people suggest a stepper expander as seen here (Adding more extruders - RepRap). But I am not able to find this on amazon to ship for my project in time.

Is there anyway I can run the 6th motor on an uno and somehow have the mega and uno communicate with each other?

2a. Could I use the extruder bed power points to power a solenoid + relay and use any remaining pins eg. thermistor pins to tell the arduino when I want to turn on the solenoid?

2b. If 2a isn’t possible can I have a solenoid circuit separate on an uno and somehow communicate to the mega controlling the ramps?

Any help/links would be greatly appreciated. I feel like I’ve been reading forums and watching videos for two days but I’m having a hard time understanding some aspects of the board and arduino as they apply to my project.

If you have any other suggestions for motor controllers I could order please do let me know. I came across ramps as I saw many people using it for hobbyist projects so I thought it would work for my application (plus i can order it off amazon prime).

[Robin2]

Images from Original Post so we don't have to download them. See this Simple Image Posting Guide

...R

[Robin2]

yeoyeo:
Is there anyway I can run these independently?

That part is easy to answer - NO. Not if they are connected to the same driver.

I'm not an expert but I think when two motors are connected to a single stepper driver they should be connected in series so that the same current flows through both motors. Connecting them in parallel seems likely to overload the driver.

I suspect you will be much more likely to get useful advice about this problem on the Reprap Forum.

...R

[Grumpy_Mike]

Connecting them in parallel seems likely to overload the driver.

Most mechanical designs require two motors to be driven at the same time and all the circuits I have seen have the motors in parallel. As these stepping drivers are controlled current devices, there is little or no danger of overloading them.

[Robin2]

Grumpy_Mike:
As these stepping drivers are controlled current devices, there is little or no danger of overloading them.

Indeed. But if you have a driver that can provide 1.5amps and a single motor that uses 1.5 amps everything works sweetly. If you then add a second 1.5amp motor in parallel the driver won't be able to supply the 3 amps required. If they are connected in series the driver can supply 1.5amps through both motors (assuming the power supply voltage is adequate).

I suspect the more common arrangement is to have a driver for each motor and feed the same step and direction signals to both drivers.

And none of these arrangements can guarantee that the two motors remain in step.

...R

[Grumpy_Mike]

I suspect the more common arrangement is to have a driver for each motor and feed the same step and direction signals to both drivers.

Well if we are considering 3D printers the most common arrangement is to have them in parallel. The point being is that the Z axis does not require twice the power of the other axis, just that it is spread evenly over two sides. So running two motors at half the power each is absolutely fine.

[yeoyeo]

Thanks. I will try to ask on the reprap forum!