I am very new to the motor/motor shield world, and the Arduino for that matter and would like some help. I am currently working on a project that requires me to control two stepper motors with a pretty high torque as I will be moving an entire window (it's supposed to be an automatic moving window). How would I power the two motors/what kind of external battery supply will I need in order not to damage the Arduino or any components?
Why stepper motors? Why not a linear actuator? Some more details are needed. Phrases like "pretty high torque" aren't helpful, your idea of "pretty high" could mean almost anything.
I am currently working on an automated window system, where the system can detect rain through an app and automatically close the window from there, or open if the temperature gets too hot. I need two motors (one for automatic blinds and one for the window), and am thinking about using stepper motors since those don't require a feedback. I will drive the motors using the Adafruit motor shield. Only problem I am having is what kind of external battery supply will I need? I am fairly new to the Arduino world and would really like some feedback/advice.
It is hard to recommend anything without knowing how much current, voltage and time used by the project. You need to flesh out your requirements so you have solid numbers to work with.
I though stepper motors would be better since they do not require a feedback, making it easier to control when to start and stop the window. Since I am very new at this, I thought using a motor would be much more easier to figure out.
Batteries are not really suitable for powering stepper motors because the motors are very inefficient and consume almost the full current when stationary in order to hold position.
A stepper is easy to position but you will need something that allows the Arduino to detect when the motor is at the zero position every time the Arduino starts.
A diagram of the mechanism you want to move would be a big help - both to understand the motor requirement and the positioning requirement. How much control of the position do you need?
A DC motor driving a threaded rod could be used as a linear actuator. And it would hold position without any power.
I though stepper motors would be better since they do not require a feedback
You're going to need some king of 'feedback'. Let's suppose it takes 5000 steps to open or close the window. But 5000 steps from where? How are you going to determine where the window's current position is? You could assume that the last operation closed the window and therefore can assume that the widow is closed. But did the stepper miss steps during the last operation? Perhaps it is not closed but 345 steps away from the closed position. Presumably the next operation would be to open the window. If the situation mentioned did occur, the window will try to move 345 steps beyond the open position. Will that break something?
What if the arduino loses power? Where is the window; open, closed?
I would make sure to incorporate at least 2 switches. One at each end of the window travel. But if I were to do that and only needed to fully open or close the window, I would seek another drive since there would be no need to use a stepper. Steppers are needed when any position in a movement's range must be targeted and reached. What makes the stepper less attractive is that there are an abundance of inexpensive motors with gearing that would be easier to incorporate.
- Scotty
I am currently working on a project that requires a casement window to open and close automatically through the use of an online applet. I am having trouble trying to decide which motor I need to control the window. From what I have researched, a stepper doesn't require a feedback mechanism whereas a servo does and a stepper is easier to control in terms of when it should stop and also has a higher holding torque? I have never really worked with any motors before and would like some opinions from those who have a better idea of which one would be better for this project.
So as opposed to stepper, would a servo work better in this case? Since we are doing it automatically, would we need sensors in order to tell the motor when to stop turning as its feedback? Sorry if any of this sounds stupid, this is my first time working on something this intricate (for my level of knowledge) and am trying to learn as much as I can.
thrainbow:
So as opposed to stepper, would a servo work better in this case? Since we are doing it automatically, would we need sensors in order to tell the motor when to stop turning as its feedback? Sorry if any of this sounds stupid, this is my first time working on something this intricate (for my level of knowledge) and am trying to learn as much as I can.
Post a diagram of the apparatus you want to move and give us some idea of weights and dimensions.
Without those basic facts it is impossible to give useful advice.
...R
Why don't you tell us a little about what this motor has to move? Doesn't that seem like it would be some important detail for a question like this?
Steppers are usually cheaper than servos.
With a stepper you'll need a limit switch to provide a reference starting position.
Holding a window in a fixed position with a servo or stepper motor will consume power all the time. Perhaps think about a brake or latch so the motor can be powered down until needed.
thrainbow:
I am currently working on an automated window system, where the system can detect rain through an app and automatically close the window from there, or open if the temperature gets too hot. I need two motors (one for automatic blinds and one for the window), and am thinking about using stepper motors since those don't require a feedback. I will drive the motors using the Adafruit motor shield. Only problem I am having is what kind of external battery supply will I need? I am fairly new to the Arduino world and would really like some feedback/advice.
I think steppers are dangerous in this application, they can produce lots of force (more at lower speeds)
without anyway to sense the force. If someone gets caught in these windows the stepper is just going to
push harder if it encounters resistance and cause injury.
If you use a DC motor and limit switches / encoder you can monitor current and detect obstructions
and shutdown.
Hi,
If this is going to be in the environment and you need torque, use a linear actuator.
Google linear actuator
They are setup ready to mount, sealed against the environment, have built in limit switches and potentiometer feedback.
Motor, gearbox and pushing arm all in one.
You then just need to control DC power in most cases, and read the position feedback.
Feedback is not a problem, in fact its a help.
Tom..... 
Delta_G:
Why don't you tell us a little about what this motor has to move? Doesn't that seem like it would be some important detail for a question like this?
As described in my post, we are working on an automated window, so the motor would be in charge of moving the window so that it closes and opens.
TomGeorge:
Hi,
If this is going to be in the environment and you need torque, use a linear actuator.Google linear actuator
They are setup ready to mount, sealed against the environment, have built in limit switches and potentiometer feedback.
Motor, gearbox and pushing arm all in one.
You then just need to control DC power in most cases, and read the position feedback.
Feedback is not a problem, in fact its a help.Tom.....
The thing is we are planning to use something called the Particle Photon microcontroller since we are planning on connecting it to the weather app that the microcontroller is already configured to. I'm not really sure whether the linear actuator could be compatible with it or not?
thrainbow:
As described in my post, we are working on an automated window,
We know that.
I have asked twice (this is the third and last time) for a diagram of the system and dimensions and weights.
It may surprise you to know that there are different sizes of windows and a wide range of opening systems.
...R
Hi,
I'm not really sure whether the linear actuator could be compatible with it or not?
Can you tell us your electronics, programming, Arduino, hardware experience?
You need to do some research, if your controller can control a stepper, it will have no problem with a simple DC motor and driving circuit.
Tom...