TYNGSBOROUGH, Mass. - The knock on Brian Hart's door came at 6 a.m. An Army colonel, a priest and a police officer had come to tell Hart and his wife that their 20-year-old son had been killed when his military vehicle was ambushed in Iraq.

Brian Hart didn't channel his grief quietly. Committed to "preventing the senseless from recurring," he railed against the military on his blog for shortcomings in supplying armor to soldiers. The one-time Republican teamed with liberal Sen. Edward Kennedy to tell Congress that the Pentagon was leaving soldiers ill-equipped.

And then Hart went beyond words to fight his cause. He became a defense contractor.

He founded a company that has developed rugged, relatively inexpensive robotic vehicles, resembling small dune buggies, to disable car bombs and roadside explosives before they detonate in hot spots like Iraq and Afghanistan.

Now, Hart has won over the military brass he so harshly criticizes. Three years after starting Black-I Robotics Inc., Hart and his four employees won a $728,000 contract from the Pentagon in June to further develop the "LandShark" robot..........