Posting here because this is the closest thing I could find to an Audrey newsgroup.
I am using a 3COM Audrey. I would like to take it to the back yard or the middle of the living room without having to run a long AC cable to it. Can anyone recommend any battery solutions? I don't just mean an Audrey battery pack (since I don't think they exist); something like a UPS that I could charge from an outlet and then let the Audrey power from it for n hours would be good.
Thanks.
Try these:
The stock power supply puts out 3.3@1.5Amps and 5.0@2Amps. You could power it for a while on something like a 6v motorcycle battery using some voltage regulators to drop the voltage.
Here is the pinout:
I just noticed you found the I-Appliance BBS (linux-hacker.net). But I will post this anyway...
Thanks for the reponse. I had seen the 2001 question on the linux-hacker board, and a few other posts elsewhere on the web, but I had never seen a clear HOWTO or site that simply sells a solution.
The Audrey isn't the first luggable item that needs power, so I figured there was something out there. I really don't have the skills to work power pinouts and etc. What would a 6v motorcycle battery look like, and how would that itself be charged? See, I am a lightweight. :)
I have recently hunted around presentation equipment companies for solutions (eg something that would extend a laptop's power without having to swap batteries) and still come up dry.
Hmmm..
Audrey is not the first thing to need portable power but it's power plug appears to be unique to itself so you won't find a "off the shelf" solution.
have you checked with the people at audreyupgrade.com about building you something? They should have the parts and expertise to fabricate something. Drop them a email.
The motorcycle battery approach requires some fabrication and circuit design skills. If you decide to fool around with batteries be sure to use a fuse.
The cheapest solution is likely a UPS to power the stock power supply. This is not very efficient since the 6 or 12 volt DC battery in the UPS will be stepped up and converted to 120 volts AC only to be stepped back down and converted to 5 and 3 volts DC in the Audrey's power supply. With each change power is lost in heat so the Audrey will not run as long from the same size battery if you were to go the motorcycle battery and voltage regulator route. However with a 500VA UPS selling for around $50 it is worth a try. The problem may be that the Audrey power supply may not draw enough current to start the UPS. If you are going out to buy one be sure there is a decent return policy...
I did check with the folks at audreyupgrade.com. They answered 1001 and questions I had, and were very patient and knowledgeable. They are not willing to build a one-off custom solution for me, but might do something for sale in the future if enough demand was identified.
Sooo....
I think I found a solution:
Sounds like what I need. The picture is a little small on the site, and I am not sure if I need to buy anything else (eg does this pack plug into an AC outlet itself to get charged), but it looks promising. I think I can just plug the Audrey wall-wart DC brick into it and run portably.
What do you think?
That unit is a bit ugly and appears to have the inverter outside the main unit. I would look at Xantrex. Everything is built in.
Eh, looks like the wrong idea. It's just a car jumpstarter with an inverter plugged into it's cigarette lighter socket. Not very portable and rather overpriced as well!
so the circuitry that you would need to get these two voltages is essentially already in your existing power supply. I would look into hacking that power supply to accept low voltage DC instead of 110V AC. Internally, it probably uses a transformer to get the voltage down to 9 or 12V AC and then uses additional circuitry to step down to 3 and 5V DC.
I'm not an expert in electronics, don't own an Audrey and have never seen their power supplies, but my guess is that if you rip the transformer and the AC/DC converter out of the power supply, and connect a powerful 9 or 12V battery at that point, you would have everything you need.
If you're real handy, you could break the circuit on the board and make it switchable between 110V AC and battery powered. So you could still use it plugged in as well.
Peter
Most power supplies these days are of the switching variety instead of the older transformer type. Unless you know what you are doing you don't want to be messing around with switching supplies. They can knock the #@%$ out of you!
A battery and two voltage regulators is a trivial circuit for anyone with experience in electronics.
ok, never mind my ignorance - last time I played with power supplies they were still all transformer based. I put google to work and couldn't find any mass production DC/DC converters with dual outputs, but I did find a component that seems perfect for this application; the Max1630-Max1635 power supply controllers for notebook computers.
If you can read a datasheet and use a soldering tool, you can build your own dual output 3.3V/5V DC/DC converter with this:
hope this helps. Peter
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