I am planning a project that will require two rows of multiple stepper motors, that are moving in sync.
My idea is to have them wired in parallel so I only need to send two separate 4-wire-control outputs from one Arduino, each for one entire row of motors. For now I am planning this with 2x5 28BYJ-48 5V stepper motors with an ULN2003 motor controller each, and a separate power supply for all of the motors. the data sheet of the 28BYJ-48 says it uses 5V and has 50Ω Resistance, so a 5V 2.5A power supply should be able to supply 10 of these motors.
Only if it turns out that I have to add more of these or use bigger motors, I have to get a power supply with higher current rating, or I use one power supply for each of the two rows of motors.
Thanks! That strip board was more to be able to visualise this in Fritzing, in reality this will be cables because the motors are at least 50cm apart each.
Okay great, thanks!
Of course, the two power supplies would be connected like shown in the schematic.
So I need a 7V source for this to supply the motors with the 5V it needs, do I understand that correctly?
If I understand you correctly, then all 10 motors should move in sync.
Five clockwise, and five anticlockwise.
To make sure, you should drive all motors from the same four Arduino pins.
Pin order determines motor step direction.
Have fun working it out.
No, forget about the comment in post#2.
5volt for motor+ULN is more than enough.
7volt for motor+ ULN would result in a bit more torque and rather hot motors.
Leo..
Not necessarily, I just need the five motors in the top row to be in sync and the five in the bottom row to be in sync, and the top row has to be able to move in a different speed and direction than the bottom row, that's why I was planning to do 2x separate four pins to control each row
I have one more question: All versions of the ULN2003 board I could find have pre-soldered header pins on them. I would like to make this permanent and solder the wires directly to the board, would you recommend desoldering the header pins and removing them, or is it okay to solder the cable onto the header pin instead of directly onto the board?
Can't you solder the wires to the underside.
When I had to space out 48 of those motors I did cut the motor wire, and extended that.
Leaving the board and connector intact.
Leo..
Ah I guess I was a bit unclear... I want to solder the cables to the IN1, IN2, IN3, IN4, pins on the board as well as the VCC and GND connections. As mentioned earlier, the strip board won't be there in reality, instead I will have cables that branch out to each motor.
My curiosity has been aroused. How would you or anyone looking at your project be able to tell if the motors were synchronized or even moving in opposite directions?
Hi,
Have you worked out how to make sure they all start in the same position when you turn your project on?
Because when you turn your project off, the knowledge of the steppers position will be lost.
Have you tried getting at least one stepper working and used a DMM to measure the current?
Will the steppers be under any load of just turning a light load object?
Yes I know about that, first I was planning on using limit switches to do a calibration when starting up the Arduino, but I found that this wouldn't be necessary as I can control the position of the parts that the motors are moving and manually set them to "zero" before starting up, and then working from there.
Not yet, but I do have one of them now to make some tests before building the whole thing.
Yes I guess that would describe it best. The motors would have spools attached and move strings, so there would be some light load on them but the torque of these motors is sufficient to do this just fine.
I don't understand the question. How would someone not notice a motor moving out of sync or in the wrong direction?
Because when i tried one of those steppers, I had to put a piece of tape on the shaft to detect the motion and direction. Someone even a few feet away would have the same problem.
@Paul_KD7HB Of course this is not about the motors themselves, they will be used to move something around in a coordinated motion, and you would certainly be able to see it if one motor steps out of line.
