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makes something that runs on battery, run on wall outlet

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peppers

New Member
i have this vacuum canister for coffee that uses 4 AA bateries to run. this is a very stupid idea b/c it sits next to a wall outlet and it eats batteries like crazy b/c every time it detects a lose in chamber pressure it starts pumping. i want to make it so that it does not run on batteries but instead runs through a wall outlet. what would i need to buy and what would i need to do to make this happen. it does not look difficult i just dont know how to do it with out burning down my house. thanks
 

KMoffett

Well-Known Member
You need a DC wall-wart that will output 6 volts DC at a current sufficient to run the motor (my guess is > 1A), and a dummy battery pack. I did this for my wireless doorbell. 4 C-cells for each of 2 chime units. $$$$ 3 times a year. The battery pack is to connect the wall wart wires to the battery compartment.

Got a photo of the battery compartment?

Ken
 

peppers

New Member
the battery compartment just has 4 batteries in a row. each facing the opposite way like in an old gameboy or something. why do i need dummy batteries? can i use wire to connect all the battery terminals together? where do i get a wall wart? give me a link if u can. what do u mean by "$$$$ 3 times a year?" i dont understand. thanks
 
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KMoffett

Well-Known Member
"$$$$ 3 times a year?" was what I was paying for replacement batteries. :(

The dummy batteries was just a way of connecting to the unit without soldering into the existing terminals. You can connect it any way you want. Companies like Mouser Electronics or Jameco Electronics have wall warts that should work. Not knowing the exact current requirement of your vacuum pump, I can't recommend a specific one. My guess is that any one with a current rating higher than 1 amp should work. Go for 2 amps to be safe.

Ken

Ken
 

Sceadwian

Banned
You don't need dummy batteries, if they're opposite facing like that they're series so all you need is the first + lead and the last - lead and you solder the power cord leads on, just make sure you get the polarity right. I just wired a set of LED desk lights that ran on 3 AAA batteries using only two wires, and no dummies. The current requirements for a motor are going to be high, test the power supply before you solder it on. 2 amps like KMoffett suggests sounds good just don't do too much more as the motor will use it at the start and it could be bad for the unit.
 

Frosty_47

New Member
Just get a regular 6V adapter (forget all that wall wart B.S.). For your needs 500mA adapter will most likely do the job however, I recomend you get 750ma - 1Amp adapter to be safe. You can pick one up for less than $10 at any store that sells electronics components. Just remember that the wire that has a white stripe on it is your Negative.

---Hope This helps....
 

Sceadwian

Banned
Frost you feeling okay?... a regular 6V adapter is a wall wart =)
 

Frosty_47

New Member
Frost you feeling okay?... a regular 6V adapter is a wall wart =)
Yes, I was attempting to simplify things. Wall Wart is not familiar name to the general public (especialy to the sales people at the counter). So when you mention an adapter to the ppl at electronic stores, they will know what you are talking about, as opposed to just giving you a puzzled look...
 

Sceadwian

Banned
Anyone working in an electronics store that doesn't know what a wall wart is needs to be fired, or at least informed =)
 
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Frosty_47

New Member
Anyone working in an electronics store that doesn't know what a wall wart is needs to be fired, or at least informed =)
Lolz I agree however, in that case there will be not one employee left in the store unless its Electrosonic but thats about the only one place I know where employees know the products they sell (at least somewhat).
 
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NukeMan06

New Member
I agree with Frosty Most people that didnt go to EE school dont have a clue what a wall wart is. What i recommend saying to the clerk is where are AC/DC Power Adapters if they dont understand that then they should be fired lol.
 

NukeMan06

New Member
One other thought, the motor on this coffee vacuum thing is probably controlled with a small microcontroller which is sensitive to voltage ripple. A 6V wall wart in most cases is not going to output exactly 6v dc without some ripple. I would check to see if there is a voltage regulator circuit inside the device if not you run the risk of ruining the controller.
 
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Sceadwian

Banned
A micro controller in coffee vacuum? I'm all for using micro controllers, but that is most definitely NOT a place I would think to find one =) It's probably just a very basic vacuum motor with possibly an air pressure activated cutoff switch. I'd be more worried about a wall wart being able to supply too much current relative to the batteries and burning out the motor. 4AA's in series is a pretty decent amount of series resistance so it should self limit the current, a wall wart will give as much as it can.
 

Hero999

Banned
Use a 5V regulated wallwart if you're worried about fluctuation in the supply.
 
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