Damaged computer from arduino?

[tpg]

Hello,
I had my laptop connected to the arduino uno with the motor shield. External power supplied to the motor shield from a 18 volt drill battery.
Stepper motor worked ok connected to motor port 3 and 4, when I connected a dc motor to motor port #1 and downloaded the soft ware to test motor I accidently connected one of the motor wires to the center ground tap and Poof!! Magic smoke from the L293D. The USB cable was still connected to the computer and now the
laptop computer is dead. I did not know the computer would be damaged through the USB port. Any suggestions?
Thanks,
TG

[Franklin97355]

18 volts on any ground can do damage. If it's just one port you may be able to live with it or you can get it repaired. Also it was not the Arduino as your title says that damaged your computer, perhaps you could reword that?

[adafruit]

I had my laptop connected to the arduino uno with the motor shield. External power supplied to the motor shield from a 18 volt drill battery. Stepper motor worked ok connected to motor port 3 and 4, when I connected a dc motor to motor port #1 and downloaded the soft ware to test motor I accidently connected one of the motor wires to the center ground tap and Poof!! Magic smoke from the L293D. The USB cable was still connected to the computer and now the
laptop computer is dead. I did not know the computer would be damaged through the USB port. Any suggestions?
Thanks, TG

wow! we've never heard of this happening before, but based on what you said we believe it's definitely possible to damage any computer with what you were doing (that's a pretty dangerous recipe). although you said you accidentally connected the motor wires to ground, we don't think that is what could have damaged the computer - what's more likely is the 18V somehow was connected and fed in to to the USB and that can definitely damage a computer. there is some protection for USB but 18V is pretty high and it also depends on the computer of course.

-adafruit

[OLIMEX]

next time you can use USB isolator to protect your computer

Best regards
Tsvetan

[tpg]

Thanks Guys,
My computer was a Dell Insprion 1526 using Windows Vista.
Now when I turn it on the leds flash twice across the top of the keyboard and I hear a rurru, rurrr then nothing happens. After that if I do not turn it off the cpu gets hot and the cooling fan will come on. You think the whole thing is fried or maybe just the usb port? It has four usb ports.I took the back cover off and found the copper cooling thingy that connects to a heat sink and it would get hot to the touch when I would turn it on.
Do not know if the arduino uno or the motor sheild is ruined or not. I will definitely buy a "usb protector" when I get this straightened out.
Do you think it would be safe to connect just the UNO board to another computer? I will order a new L293D chip and socket for the motor board.
Any advice is all good for me.
Thanks for the comebacks
TG

[adafruit_support_bill]

Do you think it would be safe to connect just the UNO board to another computer?

The Uno by itself should pose no danger.

Drill batteries are another story. They are designed for very high discharge rates and at 18v can do a lot of damage in a hurry. As Adafruit said, there is typically some overload protection on the USB ports, but it is probably not designed to handle something like that.

[Agent24]

Probably the USB controller is integrated into the southbridge chip and you've blown that up.