axis 2100 camera only runs 12v ac

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I have an axis 2100 webserver cam that runs from a 12vac plugpack. I
want to run it on 12v dc and it refuses to work. It seems to want ac,
perhaps the 50hz for a clock or something.

I DONT want to have a 12v>240v inverter just to run this as
the camera will run from a car battery and solar panel so dont want to
waste power.     Can I trick the camera by somehow making a 50hz
oscillator and somehow mixing it on the gnd line  of the 12v dc??
Im not sure how to do this.

Any tricks/tips/links to a circuit appreciated.


Re: axis 2100 camera only runs 12v ac



Axis has a mailing list, you might find more answers from there.  They've
changed their website, so I'm not sure how to find anything anymore.  The
mailing list is at snipped-for-privacy@axis.com.   You might try sending that
address an email with "Subscribe" as the subject or body.

Dan

On Thu, 22 Mar 2007 15:55:11 -0700, lentildude wrote:

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Re: axis 2100 camera only runs 12v ac



"lentildude"

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** Most devices that run off AC plug packs do so in order to generate
internal DC rails of both polarities.

 Some employ voltage multiplier ccts to generate DC rails of double the peak
AC voltage.




........   Phil






Re: axis 2100 camera only runs 12v ac


put finger to keyboard and composed:

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Assuming your camera can tolerate a square wave, use a H-bridge to
convert your 12VDC car battery source to AC.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: axis 2100 camera only runs 12v ac


I was looking at inverter circuits, I would need 12vac at 1 amp but
would need to be efficient to not
drain car battery.   If you have any links to any simple low cost
circuits, most appreciated

BTW

Here is a look inside the 2100
http://www.alttokyo.com/Jauction/2100.JPG
I took a hires picture, you can see a little of the powersupply input
circuitry.




Re: axis 2100 camera only runs 12v ac


put finger to keyboard and composed:

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See http://www.axis.com/products/cam_2100/2100to.htm#hard

 The AXIS 2100 consists of:

  Power connector (12 V AC or DC, 9.6 VA), Axis PS-D
                              ^^

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Re: axis 2100 camera only runs 12v ac




lentildude wrote:
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How many amps does it need?

If your a scrounger, find a 9 volt or so DC wall wart that has
screws in it rather than being welded together.

Break the case open. Take the diodes and caps out and run directly from
the transformer secondary. Might be close enough to work.

Bob

-

Re: axis 2100 camera only runs 12v ac



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Maybe a closer read of the original question is needed here. This answer
aint gonna help. He's got a 12v AC plugpack, but wants to run the camera
from a 12DC source (actually, a car battery I suspect).



Re: axis 2100 camera only runs 12v ac


Lentildude,
            Probably the AC is used to generate the negative bias for
the camera IC thus a square wave drive will be fine.

I would suggest a small microcontroller driving a H bridge circuit.

A PICAXE chip should be cheap and easy to program to generate a 50Hz
signal on 2 different output lines.

If accuracy is required then a 32KHz watch crystal could be used to
stabilise the frequency, but a firmware program would have to be written
and burned to the chip with a PIC programmer.

Several different H bridge circuits can be found at

http://library.solarbotics.net/circuits/driver_tilden.html

I hope that this helps.

Regards,
        Brenden Ede


lentildude wrote:
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Re: axis 2100 camera only runs 12v ac



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If you connect anything to the ports then be careful, as they may have
assumed that the source of AC power would be completely floating, so they
might have grounded either side of the AC input to the signal ground, or
they might feed it to some rectifiers to generate positive or negative
supplies or both, and they may have chosen to use any of those power rails
as the signal ground for the other connectors.  If your new power source is
not floating with respect to whatever you plug into the ports, then bad
things might happen that the designers of the product had not intended.

I suggest tracing the part of the circuit around the power input, if that is
feasible, or use an oscilloscope to measure the waveform on both terminals
of the AC input with respect to the signal ground of the other ports, when
the device is working normally from the proper AC adapter.

Chris

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