Let's Make Robots!

Need help in choosing the board or microcontroller

Hi,
I have been searchinf for hours adnd now I have came here to get some help in my problem.
I wanna control 6 dc motors of 48V. I wanna run them through image processing, So kindly suggest me some board or microcontroller for this. I have looked at arduino and raspberry pi. But I am confused which one I should get??????


And my next question is that I have calculated distance b/w object and my robot through image processing, now how I can send this distance to robot's motor that should move for some specific time???????????
Thanks! 

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If the image processing is being done on a regular computer your probably best off with arduino rather than the pi. Pi has alot of IO constraints which had you bothered doing your research you would have immediately seen as a limiting factor. Hell, even if you were doing the image processing on the pi (openCV+the official CSI camera give excellent results compared to when people had to use webcams, but it still might not be enough), you would still be glad to have an arduino or something to control your motors because the pi frankly isn't so great at that.

I think I have almost solved the problem of driving 48V motor!
Motors are of 48V and it's stalling current is less then 1A, almost 0.6A,0.7A. I have h-bridge. And I am giving driving voltage of 48V through H-bridge to run motor. Now I think I just have to connect PWM pin with arduino PWM pin.

Sorry all guys for such a confusing post, I'm gonna correct it. I was in great hurry when typing it.

If you don't know how to control some motors then I think this project is too advanced for you.

First of all, there are not many hobby robotic motor controllers that will work at 48V. You have not told us what the motors stall current is. Without that information no one can suggest the correct motor controller for you. If you only want to drive the motors in one direction then you can just use a FET.

When you know the stall current then look at SparkFun and Pololu for a suitable motor controller. If you cannot find any that are rated for that voltage and current then you will need to look at sites for industrial controllers such as Ocean Control.

I would suggest you change to motors that are 24V. It is much easier to get controllers that work at this voltage.

 

Motors stall current is less then 1A. I wanna drive them in dual direction.

Stop doing this "???????????"

It is stupid, it makes you look like a moron, and I am getting damn sick of it.

Fix this post now.

Sorry for confusing post! Infact I was in hurry when I was Posting it. Now I'm fixing it!!!!

To answer the motor control question, I will offer some ideas in that thread.

Last question first. How to move motors a specific distance.

I would suggest you look at encoders. Knowing the circumference of your tires and how many pulses per revolution will allow you to manage to control motors pretty well with respect to moving a set distance.

First question last because it is more difficult to answer.

You want to (paraphrasing) take a picture and figure out distances based on some unstated data. I say unstated because all you have said is you want to calculate a distance from a b/w image. IF you had 2 cameras, and, IF you were doing some fancy calculations with the two pieces of data, you might be able to approximate a relative distance to the object. That being said, I am not sure either one of the two boards you mentioned will have enough "horsepower" to do anything with that much data in a reasonable timeframe. I can pretty much assure you that an 8bit arduino will not be able to handle the kind of image processing you are after. I would not bet that an RPi can manage to do much with that amount of data at a reasonable speed. Given that you are running 6 48v motors, you might be able to step up to a used laptop or a small form factor (ITX/mini ITX) board.

Once you more explicitly state how and what. I believe you will get more, better answers. 

I got your last question's answer :)
And now more details about first question!
I am taking images from a bluetooth webcam and then taking images constantly at specific intervals. I am doing this in laptop in Matlab. Then after image processing, I have calculated the distance b/w the object and robot. Now my question is that how I can send this distance to robot through arduino. 

Serial comm to Arduino through Matlab:

http://www.mathworks.com/help/simulink/ug/configure-serial-communications.html

Motor Control with Arduino: A Case Study in Data-Driven Modeling and Control Design

http://www.mathworks.com/company/newsletters/articles/motor-control-with-arduino-a-case-study-in-data-driven-modeling-and-control-design.html

I don't know if they're any help but they came up on Google after searching out of curiosity. I don't speak matlab but the last one looked full of info lol