DC Motor through Serial Port

[shyam4uall]

How can i control two bi-directional motor through PC serial port ?

Please help me asap.Any website links would also help but if anyone gives his personal experience then its better.

[airman00]

you have quite a few options for a serial port motor driver
I will need to know your budget and how much amps and voltage the motor draws.

Heres one option for one 10AMP bidirectional motor to be controlled through a serial port-  http://www.pololu.com/catalog/product/120
Another , more expensive, option is the Phidgets Motor Controller - http://www.phidgets.com/products.php?product_id=1064

EDIT: I found this tutorial - http://www.strout.net/info/robotics/tutorials/Pololu0410.html

[Admin]

also, the sabertooth at dimensionengineering.com

[shyam4uall]

one..more thing is that i am unable to chose a motor and its torque rating.My bot would weigh around 10-12 kgs including the 2 motors and batteries and a 2.25 Kg laptop.What would be a typical current rating and what should be the torque rating of each motor to carry the weight ?I would use two wheel of 70mm diameter and 2 castor wheels.

Also to make the motor driver i think L293D would not work,what should be used in place of that ?L298 would do ?

[Admin]

http://www.societyofrobots.com/RMF_calculator.shtml

[householdutensils]

If you don't want to go with the pre-made solutions, my rudimentary understanding is as follows :

Under Linux, you can just use a regular H Bridge like the one detailed on this site and then write bits to the serial port to turn the control lines high or low, just like if you were running it offa mcu. You can find numerous tutorials on the net detailing writing and reading from the serial port.
 
http://www.societyofrobots.com/robotforum/index.php?topic=5729.0

I wrote an example in the above post about writing to the parallel port so if you've got one of those, it might be a good alternative to a serial port.


Under windows 2000 and later things get a bit more complicated because of the port security features of the kernel, and you're better off using a commercial controller that comes with software because otherwise your going to have to write a kernel level driver.

One more thing. You should be careful with your serial port, chucking some octocouplers between the h bridge and the serial port will reduce the chance of frying your serial bus.