multipal stepper motots with touch screen controll

Hey guys, i'm a newbie to Arduino uno and while learning code to make it blink is cool i want to advance. I have a project that is like this:

I have 24 small stepper motors Specs here, very small.

Dimensions Size: 50 mm square × 11 mm1 Weight: 90 g Shaft diameter: 5 mm

General specifications Steps per revolution: 200 Current rating: 1000 mA2 Voltage rating: 4.5 V Holding torque: 14.16 oz·in Resistance: 4.5 Ohm2 Inductance per phase: 2 mH Number of leads: 4 Lead length: 30 cm

Touch screen dispaly:

https://www.sparkfun.com/products/11740

I would like each one to rotate 1 revolution in 1 hour, then if i want to select say #5 motor to rotate to a certain point (pre programmed for position 1,2,3,4) i could do that with the touch screen display and then once exited the screen it would go back into formation with the rest.

What would i need to make this happpe? would i need more than 1 uno and a easy driver (sparkfun) or would i need mulltipal UNOs to do this ?

Current rating: 1000 mA2

?

A "servo" (as in the thread title) suggests some form of feedback. What does this mean?

I meant stepper motors :)

And amps squared?

https://www.pololu.com/product/2297

The link from a supplier

Are you saying you have 24 of those motors - each requiring 1 amp of current ? Stepper motors draw their full current even when stationary.

What stepper motor driver boards are you using? You will also need one of them for each motor - perhaps Pololu A4988 drivers.

What power supply are you using for the motors - volts and amps?

Have a look at stepper motor basics and this simple stepper code. The second version (using millis() ) should be adaptable to your requirement.

Do you want the motors to be controlled independently or could several (or all) motors be controlled using a single step signal from the Arduino?

...R

Robin2: Are you saying you have 24 of those motors - each requiring 1 amp of current ? Stepper motors draw their full current even when stationary.

What stepper motor driver boards are you using? You will also need one of them for each motor - perhaps Pololu A4988 drivers.

What power supply are you using for the motors - volts and amps?

Have a look at stepper motor basics and this simple stepper code. The second version (using millis() ) should be adaptable to your requirement.

Do you want the motors to be controlled independently or could several (or all) motors be controlled using a single step signal from the Arduino?

...R

Hi Robin, since i would like each of them to spin at the same time but when selected one can spin faster to display different angles seems like i may need to have them on individual because if i use one signal from the UNO to control all Steppers then they cannot spin individually.

I have only the uno and motors, i know i need a stepper driver but for all units and the way i want to set them up i need to get 24 drivers ?

it will be 2 12V ac/dc inverter for the 24.

Im new to Arduino so i want to set my sights strait and learn for my goal

epsilon: I have only the uno and motors, i know i need a stepper driver but for all units and the way i want to set them up i need to get 24 drivers ?

YES And it would probably be easier to work with a Mega which has many more I/O pins than an Uno. The 24 drivers will each need a step connection to an I/O pin and if you want to control direction for each motor you will also need a direction connection - that would require 48 I/O pins.

You could possibly extend an Uno with some external port-extender chips but that would add a lot of complexity compared with buying a Mega.

it will be 2 12V ac/dc inverter for the 24.

I don't understand this.

You will also need to consider carefully how many step signals you need to send per second when all 24 motors are working. Can a 16MHz Arduino keep up? As long as the motors only need to move slowly that should not be a problem.

...R

Robin2: YES And it would probably be easier to work with a Mega which has many more I/O pins than an Uno. The 24 drivers will each need a step connection to an I/O pin and if you want to control direction for each motor you will also need a direction connection - that would require 48 I/O pins.

You could possibly extend an Uno with some external port-extender chips but that would add a lot of complexity compared with buying a Mega. I don't understand this.

You will also need to consider carefully how many step signals you need to send per second when all 24 motors are working. Can a 16MHz Arduino keep up? As long as the motors only need to move slowly that should not be a problem.

...R

I will have 2 power supplies that are 12V each

I’ve added a simple diagram of what i would like to accomplish with each unit independently.

NOW, stepper motors from what i know cant tell where they are like a servo unless there is an added sensor no instead of adding a sensor to 24 spinning plates i was thinking of only on 1.

epsilon: I will have 2 power supplies that are 12V each

The important question is how many amps they can supply?

NOW, stepper motors from what i know cant tell where they are like a servo unless there is an added sensor

That is correct. The normal arrangement is to drive a motor step by step until it triggers a switch (optical or mechanical) so that the Arduino can say to itself "now I know the motor is at position zero".

Obviously that is more complex with 24 motors.

Sorry, although it is a nice diagram, I don't understand it.

I think it might be time for you to tell us what the project is all about. For example why can you not use sail-winch servos which allow about 3 full revolutions with full position control.

...R

Here is a video i made for more detail.

https://www.youtube.com/watch?v=c17wG6hAruk

It says that your video is private.

...R

Robin2: It says that your video is private.

...R

Fixed it

Also i want to order a stepper shield bit not sure which one, there are shields that will do multiple and some that will do one.

Having looked at your video I reckon that is an application that can much more easily and more cheaply be managed with servos. A sail-winch servo can do 3 full revolutions with position control and, in reality, there seems no reason why the models should do more than (say) 405deg in one direction and then rotate back in the other direction.

Each servo each only needs one connection to an Arduino and include all the necessary electronics.

If you look at the servo-sweep example in the Arduino IDE you will see how you can easily control the speed by making it move a little at a time.

I have not heard of any stepper shields. Unfortunately some of the motor shields are touted as suitable for stepper motors, but they are a very poor choice compared with specialized stepper drivers and they need 4 connections to the Arduino for each stepper.

...R

And there are many servo shields out there i presume, i chose the stepper bc of its low low profile but there are small servos.

I have a servo that i made continues but for this application i will have to leave it so the potentiometer in the servo can feed back to the IC so the IC knows where its at (the IC on the servo)

I guess with the servo i can have it go 300deg and then stop then go back the other way....but, how would i be able to take one model that is spinning with the rest and tell it to show me an anlge then once i exit tell it to go back to formation ?

Still thinking of useing a TFT display like what Sparkfun has:

display

video for display

video

epsilon: I guess with the servo i can have it go 300deg and then stop then go back the other way....but, how would i be able to take one model that is spinning with the rest and tell it to show me an anlge then once i exit tell it to go back to formation ?

If you use a sail winch servo you could turn much farther if you need to.

To change the angle and then return to the original angle just save the angle it was at before you change it.

I don't know why you would need a servo shield, but I believe they do exist.

...R

With the UNO i wont be able to hook up 24 servos directly, i would need a PWM shiled

like this one servo shield

For the rotation, if all of them are on a continues formation and i take one out of formation to display a certain part of the model; how can i tell it to go back to formation.

Example, if the selected model i am viewing at different angles is not in formation for 10 minutes the other models are at a different spot in there spinning .

epsilon: For the rotation, if all of them are on a continues formation and i take one out of formation to display a certain part of the model; how can i tell it to go back to formation.

I told you how in Reply #16

Do NOT use continuous rotation servos. Use normal servos so you can send them to a specific position.

If (say) the servo is a 85deg when you want to turn it to a different position you can easily send it back to 85deg later. Look at the servo-sweep example in the Arduino IDE.

...R