Let's Make Robots!

LMR's & Coursera

Wondering how many LMR's are doing the coursera " Control of mobile robots" course. I have been blown away with the global response to the course. It's my first involvement with such a course.I last attempted matices & eigenvalues over 45 years ago. Bit of a challenge now but managing 90 % at the moment. Really adds another dimension to thinking about projects.

H bridge safety

I want to drive 4 seperate motors, the largest would be 7V 550 mA and about 1.2A stall. I intend using a pair of SN754410's. Power supply will be a good 7.2V. My question is, how safe is my Arduino Duemilanove board if I use the same 7.2V supply for the motors and the micro processor. Would it be a better design to have 2 seperate power supplies. I have room.

Motor Voltage

I have a few small motors that have no specs available. I can measure the internal resistance and calculate the stall current for a given voltage or actually measure the current draw under stall conditions using say 5 volt supply to motor. But how can I determine the ideal voltage range to drive a motor without any specs?