My project:
I need twelve different stepper motors to open and close with a light switch.
When a switch is flipped, a stepper motor will pull open a blast gate door.
The door is 500g and 15cm of movement.
When the switch is turned to off the door will close again.
I am willing to change the current hardware as I realize I may need an Adruino Mega as well as it looks like this board is the most commonly suggested board and this seems to be the most common Nema 17 suggestion.
But I have not been able to find any good information on a power supply needed. It seems like I can buy something simple like this 12v 1amp from Amazon and just cut the end off.
Am I able to run 12 motors off a single Arduino? Will a single power supply be enough if no two motors will be operating at the time time? How can I even power these motors?
Can someone please just help point me in the right direction to get started. Thank you and I apologize for what I assume is a repetitive post. I am just so lost on how to start that I am not even sure how to properly ask for assistance.
The driver board linked first will burn out if you use it with a 12V power supply. It is rated for 10.8V.
Pololu has a good selection of driver boards. Choose one with a maximum supply voltage higher than 12V. You do not need a current limiting stepper driver, like the one linked second, with that high impedance motor.
Am I able to run 12 motors off a single Arduino?
Possibly, if you have enough output pins. You will need a power supply that can supply MORE current than required by the sum of all the motors running at once (700 mA per motor at 12V).
The proper starting point, and you likely have already done this: Design and build the mechanism to open and close your door using a stepper motor to do the movement. Measure the FORCE necessary to operate the mechanism. That will tell you the TORQUE required from the stepper motor. Your mechanism will also require some switch or sensor to tell when the door is open and when it is closed, so the motor can be stopped.
The torque necessary will let you size the stepper motor to fit the project.
Then you will know the power requirements.
All just one step at a time!
Good luck with an interesting project.
Paul
This is so true, but then you must design stuff that will stay in place when the power is removed. You gave no clue as the speed needed for opening and closing the door, nor does the motor need to HOLD the door in position. A stepper could be stopped and powered and hold the door, while a dc motor cannot do that.
Paul
A DC motor driven linear actuator like I suggested cannot be budged. Powered or not. Not even a "little bit".
For a task as simple as opening and closing a blast gate, an actuator is in fact a complete electromechanical solution. All it needs is to be mounted and wired appropriately.
The final goal will be 12 doors operated by independent switches. None of while will be in operation simultaneously. The doors will be approximately 15 feet apart from one another.
The doors will be mounted parallel to the ground so the door movement will be horizontal and will be able to stay open without and holding.
I guess the only reason I was looking at the stepper motor was it seemed like it could handle the torque over a long period of time, it seemed affordable, and it was a linear solution. I believe I found the same Amazon listing you found the picture of.
So the possible new goal would be to use these actuators
I will need to redo my research on what additional components this would need (I assume no driver board) but I my previous power supply question would still be relevant.
Can I use one single power supply to operate 12 of these units with the assumption that none of the units will be moving at the same time?
Thank you for the input so far. I will continue to look into the option of linear actuators and may need to restructure my line of questions when I get enough information.
That particular actuator doesn't have the stroke length that you need, but there is a huge selection of similar ones.
Yes, you need a suitable brushed DC motor driver for each actuator, or a relay board and some means of knowing where the actuator arm is positioned.
If the stroke length is chosen correctly, then look for an actuator that has built in limit switches and automatic shutoff. Then all you need to do is to cause the actuator to move to one end stop or the other.
Many such actuators have diodes to override the limit switches. In that case, if movement is automatically terminated at one end stop, you can still drive the actuator in the other direction.
How much force is needed to open, and to close the door? I guess the doors are sliding in a track?
What speed of opening and speed of closing? Do you need to know when the door is open and when it is closed?
Paul
That link had a 6” version that just isn’t carrying through with the link
The doors are on a sliding track
The doors speed is flexible and would prefer something under 1-2 second.
the doors will be visible and will easily know if they are open or closed.
That doesn't help, a stepping motor will draw the maximum current when it is stationary, not when it is moving.
So to find the current you need just find the current you are driving through one coil, multiply by 2 for the current for one motor, then multiply by 12 for the total current you need.
This will be way way bigger than 1Amp.
The data sheet says
"35 ohms per winding"
So at 12V that gives you 0.375 Amps per winding.
Giving you 0.75 Amps per motor.
So for 12 motors you need 9 Amps.
Probably the closest is a 10 Amp supply, and you will need large capacitors on each motor's supply to act as decoupling.
