Go Down

Topic: Controlling multiple motors  (Read 1 time) previous topic - next topic

aakthoo

Hello

Noob in this world. Aim to control a couple of stepper motors with an arduino pro mini.

Exact use: Trying to come up with a writing machine.
Motor control required: start/stop, direction and speed . All functions should work independently in all motors.

What exact hardware is required ?
Reading around suggests a motor driver is required to control a motor . Q) If multiple motors are connected does this mean multiple drivers are required ?
For multiple motors a 'relay' is suggested . Which is supposed to be an electronic switch ? But how does it all has to be setup ?

I am pretty lost on how to proceed. Any help please ? Or any comprehensive guide about controlling motors with arduino , that is not a book ? Like a detailed article or youtube series.

Thanks

Robin2

#1
May 02, 2019, 12:38 pm Last Edit: May 02, 2019, 12:41 pm by Robin2
Exact use: Trying to come up with a writing machine.
Motor control required: start/stop, direction and speed . All functions should work independently in all motors.
You need to give us much more detail about the machine you want to create and the roles for the different motors. How many motors?

Based on your very vague description it sounds to me like a job for stepper motors. These links may help.
Stepper Motor Basics
Simple Stepper Code

If the purpose of the project is to move a pen to draw shapes then the movements of the motors will need to be very closely coordinated. It may help if you learn how 3D printers work - for drawing with a pen you will only be doing 2D but there will be a lot of similarities.

...R
Two or three hours spent thinking and reading documentation solves most programming problems.

MarkT

#2
May 02, 2019, 02:12 pm Last Edit: May 02, 2019, 02:13 pm by MarkT
Hello

Noob in this world. Aim to control a couple of stepper motors with an arduino pro mini.

Exact use: Trying to come up with a writing machine.
Motor control required: start/stop, direction and speed . All functions should work independently in all motors.
Stepper motors just take steps+direction, your code or library generates the steps.
Quote
What exact hardware is required ?
Reading around suggests a motor driver is required to control a motor . Q) If multiple motors are connected does this mean multiple drivers are required ?
Stepper driver per stepper motor, something like DRV8825 module.  Size of motor depends on the torque required.  Supply voltage depends on the top speed wanted.  Use motors with a winding resistance in the 0.5 to 3 ohm range with modern stepper drivers.  Do not use DC motor H-bridge
modules even if they say they can drive stepper motors.
Quote
For multiple motors a 'relay' is suggested . Which is supposed to be an electronic switch ? But how does it all has to be setup ?
No, every motor needs its own motor driver/controller.  Add relays and you fry all your stepper drivers...
Quote
I am pretty lost on how to proceed. Any help please ? Or any comprehensive guide about controlling motors with arduino , that is not a book ? Like a detailed article or youtube series.

Thanks
The GRBL project is appropriate here, you can directly drive several steppers direct from GCODE, for coordinating several axes, worth a look at.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

aakthoo

offtopic: found a helpful forum. yay !



@Robin2 That stepper motor post was nicely detailed.

@MarkT Thanks a lot man. Your post is very helpful. I got a lot to process from this, but it seems I have all required knowledge to move forward. One question: I you mention to go with motors with resistance of .5 - 3ohm , but I have seen writing machines made with DVD drives, whose motors I measured to have resistance of 10/19 ohm. So? It is possible that those DVD drives had different motors OR/AND winding resistance and resistance are different things ?

MarkT

A DVD stepper motor is tiny.  The problem is finding a driver module for them, as that low current
level isn't supported by most cheap stepper driver modules (you may need a custom current shunt
resistor to be able to dial in a small enough current)

You want to do position control, a stepper is a natural choice.  Unless hobby servos are enough to
do the job.

The economics of steppers mean that NEMA17 are cheaper than NEMA14 and NEMA11 which would
otherwise be a natural fit for a smaller lower force application.  NEMA17 and NEMA23 low impedance
motors are in the range 0.5 to 3 or 4 ohms.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Paul_KD7HB

There was a similar stepper motor that came with my Arduino learning kit from several years ago. It ran directly from the Uno pins.

Paul

aakthoo

@MarkT I see. I just bought the motor driver L293D , which seems to be one of those H-Bridge things that you told not to use. But I saw lots of people using it and thought what the hell.. Any better motor driver  for a 3V 300ma motor?

@Paul That's interesting! I'll try that tomorrow

Go Up