[dorkbotnyc-blabber] voltage differences: powering a 9-volt thing with a wall socket powered device

[jeb boniakowski]

If its direct-wired to the lights, you could just unscrew the bulbs and put
in one of those adapters that converts a normal incandescant bulb socket
into a power outlet.  that would probably be the easiest thing.

(oddly, my old roommate did a proj that involved doing this exact thing last
year, and as you would expect there's some simple circuit in there that
flips a relay to power the lights.  For a variety of reasons, though, he
said once you start taking it apart its actually much easier to just build a
new circuit using the sensing element then to adapt the one in the box.)

On Dec 21, 2007 9:47 AM, douglas repetto <douglas at music.columbia.edu> wrote:

>
> It's probably just a relay that's switching the 110v wall current on and
> off when it detects motion. Check it with a voltage meter to be sure! If
> it is, then you can simply plug in a 9v DC power transformer ("wall
> wart", available at Radio Shack). That way when the sensor turns to
> power on and off it'll be just like you plugging and unplugging the wall
> wart from the wall.
>
> What does the physical connection between the sensor and the lights look
> like? If it's a 2 or 3 prong jack then just plug in the 9v DC
> transformer as you would plug it into the wall. If it's directly wired
> to the lights then you'll need to get a bit creative -- but be careful!
> Wire it up with the sensor UNPLUGGED and make sure you understand what
> you've done before you turn it on. You're dealing with 120v AC wall
> current, and if you make a mistake you can get hurt! Maybe best to ask
> someone who's done it before.
>
> best,
> douglas
>
> Jascha Narveson wrote:
> >
> > Hello, Dorkbot -
> >
> > Quick question:  i've got a 9-volt battery powered circuit which I want
> > to power with an off-the-shelf
> > turn-the-lights-on-when-the-bad-guy-gets-near-your-house motion sensor.
> > The sensor runs off normal 110 AC power, and I'm not sure what kind of
> > power it's feeding to the light bulbs, but it's higher than 9 volts.  Is
> > there an easy way to change the output of the sensor to safely power the
> > circuit?
> >
> > thanks,
> >
> > jascha
> > ........................................................................
> > .........dorkbot: people doing strange things with electricity..........
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