I am new to electronics but I need to incorporate the use of a motor into a project.
I intend to control my stepper motor by my computer via USB.
How do I connect the EasyDriver via USB?
Thanks!
`j
jonnyzwi,
Two questions come to mind:
-
Why do you want to use an EasyDriver?
-
What indicates to you that it’s suitable for your application?
AFAIK, EasyDriver is intended to be controlled by logic level signals, without much overhead. I don’t believe it has a USB interface, although one could certainly build a USB ↔ EasyDriver interface. There are, however, USB-controlled stepper drivers commercially available, including the [EiBotBoard, which SparkFun sells.
While I’m asking: Have you checked to see if the type, voltage, and current of the motor you intend to drive are compatible with EasyDriver?
Good Luck,
Eric,
Thanks so much for your message.
Like I mentioned, I’m new to electronics and so it seems I made some wrong assumptions about the components that I will need.
Maybe you would have some better suggestions as to how to implement my project.
I plan to have a small platform hanging from four thin cables - one from each corner. Each of the cables will be attached to a motor and as the motors turn (forward or backwards) the platform will be raised up or down.
I plan to have each motor running independently so that the platform can change heights independently.
I want to have a microphone collecting ambient sounds and sending them to a computer that will determine (depending on the pitch and volume of the sound) what height to lift or drop each side of the platform.
When I looked into motors, the Arduino stepper motor and the EasyDriver seemed like the most accessible (cheap and easy to use) products. I just bought one of each to test things out, but I got hung up right away when I realized that there was no way to connect via USB.
So you still suggest I try an EiBotBoard or build a USB to EasyDriver interface?
Just out of curiosity, how would that be done?
I have looked around on google to find answers to this, but I havent come up with anything.
Thanks again for your help.
Happy fourth!
`j
jonnyzwi:
I plan to have a small platform hanging from four thin cables - one from each corner. Each of the cables will be attached to a motor and as the motors turn (forward or backwards) the platform will be raised up or down. I plan to have each motor running independently so that the platform can change heights independently. I want to have… a computer that will determine (depending on the pitch and volume of the sound) what height to lift or drop each side of the platform.
You have me thoroughly confused on a rather basic question: How many degrees of freedom to you want this platform to have? In the material I just quoted, you appear to describe vertical motion of the platform, separate control of “each side” (but I don’t know whether you mean two “sides” (calling the other edges, for example “front” and “back”), or four “sides”), and independent control of each of four cables. The EiBotBoard can control only two stepper motors, so it won’t provide independent control of four stepper motors. There’s a comment on its page that indicates synchronizing two of them may present some difficulty.
jonnyzwi:
I want to have a microphone collecting ambient sounds and sending them to a computer that will determine (depending on the pitch and volume of the sound)
Is there some particular reason to use some computer with a USB interface? Why not use a microcontroller, such as an Arduino, to do the whole job.
jonnyzwi:
So you still suggest I try an EiBotBoard or build a USB to EasyDriver interface?
I don’t believe I ever suggested that you try to build a USB to EasyDriver interface. If you do need to drive four stepper motors independently from your computer, you’d probably find it less painful to use a single board that has a USB interface and can control four stepper motors. I suggest you do a bit of searching for “usb stepper motor”. I took a quick look and didn’t find an attractive USB-> 4 stepper motors offering, but I did find [this, which appears to be able to connect a single USB port to 4 stepper motor drivers. (Whether it will work with 4 EasyDriver boards, I don’t know, but that’s probably worth investigating.
jonnyzwi:
Just out of curiosity, how would that be done?
Rather like the metaphorical porcupines mate: very carefully. Seriously, I don’t think that’s a good beginner project.
jonnyzwi:
Thanks again for your help.
You’re welcome!
Eric,
Indeed, I plan to have independent control of each of the four cables.
I imagined that having a USB interface would be the easiest option for plugging the controller into the computer.
Thanks for pointing me to the Arduino microcontroller and the CNC PBX-USB controller. I have taken a look at them both, but to be honest I don’t know enough about this to know which would serve me better. It seems as if the Arduino is a more common product and so I imagine I could get more help troubleshooting it if I decide to incorporate it. Would you agree or is the CNC product better and worth using?
—Is there some particular reason to use some computer with a USB interface? Why not use a microcontroller, such as an Arduino, to do the whole job.—
From your comment, it seems as if it would be possible to implement my project without a computer at all?!
I was under the impression that a computer would be a necessary component. I thought I would need the microphone feeding info to a computer that would then send commands to a controller that could activate the motors. The Arduino microcontroller can stand alone and handle it all? As long as it can control the four motors independently, that seems to be a good solution.
Ill definitely stay away from the mating porcupines…
Thank you!
jonnyzwi:
I thought I would need the microphone feeding info to a computer that would then send commands to a controller that could activate the motors. The Arduino microcontroller can stand alone and handle it all? As long as it can control the four motors independently, that seems to be a good solution.
If you’re willing to give us some more information as to what it is you’re trying to accomplish, [southern_drawl] we’all [/drawl] might be able to give you more ideas to ponder over. I can only guess that the 4 wires are needed to be able to aim your platform (or it’s a really heavy platform). If the platform’s purpose is to aim the microphone, would an array of mics, suitably mixed, work as well ? Is the mic on the platform or does it carry something else that needs aiming ? Would a 2 servos and a pan/tilt rig work as well ?
jonnyzwi,
It’s still not clear to me what motions are intended and, therefore, how many degrees of freedom (and, therefore, stepper motors (or other actuators)) are required. If you are basing the motion on only two factors (pitch and volume), two degrees of freedom should suffice to display them.
I know you think you need independent control of each of four motors, but that doesn’t answer my question. Therefore, I will try to do a better job of asking (and add a few more questions):
Whether it will be better to use a USB->4 stepper driver board and a PC, or use a microcontroller to calculate the positions depends primarily on how you are going to evaluate the audio and how complex a process for calculating positions you have in mind.
Have you looked, for example, at [this, or the [chip on which it is based? If you can compute (without unreasonable complexity, such as FFT) your desired platform position from the outputs of that chip, then you should be able to do all of what you describe with an Arduino and one controller per degree of freedom of the platform motion.
Eric](http://www.sparkfun.com/products/10468)](http://www.sparkfun.com/products/10446)
Eric,
Thanks for your message - Ill do my best to answer your questions.
In regards to questions 1-2: I intend to have the platform lift and drop (vertical movements only), not rotate. However, I do want all movements to be automatic in response to sound.
3: The center of the platform will move up and down as a result of the corners moving.
4: My idea is to parse all audible sound into 4 ranges. Each range of the spectrum will be associated with a particular corner of the platform (ex. R1-upper left, R2-upper right, R3-lower left, R4-lower right). The height that a particular corner will raise/drop will be determined by the average intensity of volume of a particular range upon sampling.
5: I’m not exactly sure yet how much it will all weigh - perhaps around 10lbs
6: Not exactly sure about this either, although I hope I will attempt to balance the weight equally across the platform
7: I would like for the platform to move as quickly as possible. Ideally, the platform would move/react seamlessly with the aural environment. However, I realize that there are some real-world inhibitions such as speed of the motors, speed at which computer can parse and process the incoming audio input, etc.
In the end, I would like it to be as quick and organic looking as possible.
8: The total range of the platform will be small. Only around 2 total inches of vertical movement.
9: I imagined the cables being connected to the corners in order to keep them out of the way, allowing the platform to have as much surface area as possible.
Also, attaching the cables to the corners would make it easier to balance the platform and, most importantly, it would give the motors the greatest amount of leverage (strength) and precision when lifting and dropping the platform.
** I thought the idea of suspension cables would look nice. However, I have considered using 4 small elevator-like contraptions that would lift/drop the platform from underneath. Again, I envision one elevator underneath each corner, allowing for 4 independent degrees of vertical motion.
The Colorganic Spectralizer Kit and the Graphic Equalizer Display Filter look very interesting. Thanks for the links! They actually look like products that would work very well for what I intend to do.
Regarding the use of a computer vs. a stand-alone Arduino multicontroller, I am still not sure what would work out the best. Im not sure exactly what you mean by computing the platform position without too much complexity. I’m not sure what qualifies as too complex. I also dont know what FFT stands for?!
Thanks again
`j
Mee_n_Mac
Thanks for your input.
Did my recent reply to Eric give you a clearer idea of what I am trying to accomplish?
Thanks
`j
jonnyzwi:
3: The center of the platform will move up and down as a result of the corners moving.
It could, or the platform could pivot around a pair of axes that pass through its center.
jonnyzwi:
4: My idea is to parse all audible sound into 4 ranges. Each range of the spectrum will be associated with a particular corner of the platform (ex. R1-upper left, R2-upper right, R3-lower left, R4-lower right). The height that a particular corner will raise/drop will be determined by the average intensity of volume of a particular range upon sampling.
I think you need to study a bit of geometry. If you move the four strings independently, there’s a very high probability that one of them will be slack at any time. Three points define a plane and, as “you can’t push a rope”, the one that isn’t part of the definition of the plane will be slack.
jonnyzwi:
5: I’m not exactly sure yet how much it will all weigh - perhaps around 10lbs
That’s enough that I’d give careful consideration as to whether I wanted the center of gravity to move vertically. If you just pivot, that should require much less force.
jonnyzwi:
Also, attaching the cables to the corners would make it easier to balance the platform and, most importantly, it would give the motors the greatest amount of leverage (strength) and precision when lifting and dropping the platform.
“Leverage” and “strength” are not the same thing.
jonnyzwi:
Regarding the use of a computer vs. a stand-alone Arduino multicontroller, I am still not sure what would work out the best. Im not sure exactly what you mean by computing the platform position without too much complexity. I’m not sure what qualifies as too complex. I also dont know what FFT stands for?!Thanks again
`j
If you use a spectrum analyzer chip, you probably can run this in a microcontroller. FFT is Fast Fourier Transform.
Again, you’re welcome!
Eric