Switching on/off 5V power to a USB port
rcm at fuzzwad.org
Wed Apr 4 01:16:53 UTC 2012
On 4/3/12 5:26 PM, Ian Lepore wrote:
> On Tue, 2012-04-03 at 17:13 -0500, Ron McDowell wrote:
>> I just got a little USB powered fan and it sure would be nice if I could
>> have cron on my FreeBSD box turn it on or off at certain times by
>> switching off the 5V line on a USB port. Anyone know how I can do
>> that? Thanks.
>> BTW this is a pretty decent fan for the money. :)
> The usbconfig(8) command has power_on and power_off commands. I've
> never used them so I can't say for sure they'll do what you want.
> -- Ian
The good news is that "usbconfig -u 4 -a 5 power_off|power_on" works fine.
Hardware is a Dell Latitude D-430 notebook running:
FreeBSD d430 10.0-CURRENT FreeBSD 10.0-CURRENT #0 r232714M: Fri Mar 9
12:41:34 CST 2012 rcm at d430:/usr/obj/usr/src/sys/GENERIC amd64
When booting up, the fan powers up just as:
uhub7: <vendor 0x413c product 0xa005, class 9/0, rev 2.00/25.07, addr 5>
shows up, which was a pretty good clue to what device it is.
Automatically turning it on is pure laziness on my part... turning it
off is more about forgetfulness though. :)
On 4/3/12 5:45 PM, Devin Teske wrote:
> Alternatively, you could just plug your USB fan into your monitor. A
> fellow engineer and I discovered that most monitors power-down the USB
> ports when entering power-save mode (with Dell, HP, and Viewsonic,
> this is whenever the screen blanks due to inactivity; are you using
> DPMS and/or greensaver?). Walking away from the PC will cause the fan
> to [eventually] turn off, while waggling the mouse brings it back to
Devin, sorry, my monitor is too old to have USB ports on it...if it did
that would be even a better solution.
Thanks for the help everyone!
San Antonio TX
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