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Author Topic: Hardware Setup Questions  (Read 1758 times)

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Offline vidamTopic starter

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Hardware Setup Questions
« on: December 31, 2007, 10:09:23 AM »
My hardware setup consists of the following:

I have an open-source software package on my laptop that I can send velocity commands to my motors via the USB port.

My DC brushless motors have encoders built in.

Can I use a micro-controller to read the encoder values and send the encoder values back to my laptop via the USB port?

I would like to know if this is possible, before I waste too much time.

Thanks in advance,

Offline dunk

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Re: Hardware Setup Questions
« Reply #1 on: December 31, 2007, 10:37:12 AM »
it's definitely possible.
what is your experience with microcontrollers?

the way i would approach this is to connect the encoder outputs to general I/O pins on your microcontroller.
next i would connect the UART on your microcontroller to a USB to UART chip allowing you to connect it straight to another USB port on your computer.

many ready built microcontroller boards will already have a USB to UART converter built in but if you intend to make your own, sparkfun do a breakout board that has saves you from having to work with surface mount components: http://www.sparkfun.com/commerce/product_info.php?products_id=718

maybe you already have spare I/O pins on your USB motor controller?
what are you currently using to control your motors?

dunk.

Offline vidamTopic starter

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Re: Hardware Setup Questions
« Reply #2 on: December 31, 2007, 10:45:30 AM »
it's definitely possible.
what is your experience with microcontrollers?
maybe you already have spare I/O pins on your USB motor controller?
what are you currently using to control your motors?

I have *not* worked with this microcontroller a Robostix made by Gumstix. So I have to get ramped up on that part of the project too. My past experience with micro-controller was a custom-made board by some genius at MIT for a legged walker for my MS thesis at USC. I used GreenLeaf Comm++ to do the serial comms with the robot via a tether link. (Side Note, never use a tether with legged robots.)

Yes, and I am currently using the Sparkfun USB breakout kit with the Sabertooth motor driver circuit. The motor driver doesn't have any extra pins for the encoder.

I think that the Robostix will have it's own USB port to send the encoder values to the laptop.

And i"m using Java API to communicate with the motor driver. It is some code written by RoboRealm that does the communications.




Offline dunk

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Re: Hardware Setup Questions
« Reply #3 on: January 01, 2008, 04:30:03 PM »
Quote
I think that the Robostix will have it's own USB port to send the encoder values to the laptop.
i don't think so but the Robostix is just a ATMega128 based board with access to all that chips functionality so you will be able to connect another Sparkfun USB breakout kit to the ATMega128's UART.

Quote
(Side Note, never use a tether with legged robots.)
ooo. tangles.


good luck.

dunk.

Offline vidamTopic starter

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Re: Hardware Setup Questions
« Reply #4 on: January 01, 2008, 04:37:26 PM »
Quote
(Side Note, never use a tether with legged robots.)
ooo. tangles.


good luck.

dunk.
[/quote]

Thanks dunk. Not just tangles but affects the stability of the gait.

 


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