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Science Forum Index » Electronics Forum » Help Building a USB-Controlled USB Outlet?
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| Guest |
 Posted: Wed Jan 02, 2008 6:36 pm |
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I am a novice and would like to build a 120V AC outlet which can be switched
on and off by USB. I'm not sure what all I will need and want to make sure
that I'm not trying to do something much harder than it sounds. My end goal
is to have a single plug where I could plugin a lamp, TV, power strip, etc
and have the power to that device controller by a PC via USB port. Now I've
seen some devices out there like X10-compliant home automation controls and
there has always been a severe limitation in one way or another. I would
love the pulg to be grounded but it doesn't have to be if that is a
complicating factor.
It seems to me that I need a relay which can switch the 120V on/off and then
need a USB controller to control the relay. And I have seen USB controllers
which have serial interfaces on them but then how to get from a pin or two
of a serial port to the relay is where it breaks down in my head. I'm not
sure what I need between the two or if that would even work. I can handle
the software part of it once I get a hardware solution idenfitied.
Can any of you pros offer advice to get me going in the right direction?
Thanks!
Frank |
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| DJ Delorie |
| Posted: Wed Jan 02, 2008 7:28 pm |
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Guest
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Easiest way I can think of - get a FTDI 232R chip, hook up DTR to an
opto-isolated triac driver, to a triac, to the power.
Then, at least on Linux, you can toggle DTR just by changing the baud
rate to 0 (dtr off) or anything else (dtr on) via "stty" or the
termios() functions.
The FTDI chips also have some GPIO pins you can use; in theory you can
control six outlets with one chip that way (four GPIO, plus DTR, and
RTS). You'd need to use their DLL and API to do that, though. Not a
big deal if you know how to do any programming; the API is pretty
straight-forward.
You can even get a vanilla USB to Serial adapter cable, and use DTR
off that.
I have some triac circuits here:
http://www.delorie.com/house/furnace/
But the opto-triac-power circuit is pretty common; you should be able
to find schematics all over the web. I think the triac data sheets
usually have schematics too.
Beware - messing with 120v power is dangerous. This isn't a
beginner's project, although I think most beginners successfully pull
it off anyway. I know I did  |
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| TonyR |
| Posted: Wed Jan 30, 2008 2:55 pm |
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Guest
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Have a look at Diolan.com
On Wed, 02 Jan 2008 22:36:29 +0000, noreply wrote:
Quote: I am a novice and would like to build a 120V AC outlet which can be switched
on and off by USB. I'm not sure what all I will need and want to make sure
that I'm not trying to do something much harder than it sounds. My end goal
is to have a single plug where I could plugin a lamp, TV, power strip, etc
and have the power to that device controller by a PC via USB port. Now I've
seen some devices out there like X10-compliant home automation controls and
there has always been a severe limitation in one way or another. I would
love the pulg to be grounded but it doesn't have to be if that is a
complicating factor.
It seems to me that I need a relay which can switch the 120V on/off and then
need a USB controller to control the relay. And I have seen USB controllers
which have serial interfaces on them but then how to get from a pin or two
of a serial port to the relay is where it breaks down in my head. I'm not
sure what I need between the two or if that would even work. I can handle
the software part of it once I get a hardware solution idenfitied.
Can any of you pros offer advice to get me going in the right direction?
Thanks!
Frank |
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