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Topic: Converting 220 AC to 5 DC (Read 2213 times) previous topic - next topic

LiborVojtek

Hi,
I know it is really old topic, but in my humble opinion it was not fully answered or at least no consensus was reached. :-P

I think, that there might have been slight language gap, but point of the question was probably in terms of "how can I power my Adruino from mains cables dangling from the ceiling going to my ceiling lamp".

As this is a question which I am facing right now and the main problem is space as it would be quite a challenge to fit "high" transformer with other components under lamp cover. :-(

Of course safety is also concern, as hooking up just four diodes and a resistor between mains and Arduino can possibly produce "mixed" results. ;-)

So is there some small, safe solution to convert 220AC to 5DC?

Thanks,
Libor

BJHenry

So is there some small, safe solution to convert 220AC to 5DC?
Absolutely, they look something like this.

Sacharja

So is there some small, safe solution to convert 220AC to 5DC?
Yes, go to a certified electrician and ask him what can be done, and do not do that yourself, besides that the quality of the DC may be lacking, you may cause a fire in your house or kill yourself. And even if it costs a couple of hundred €, your life is still worth more.

dochawk

I think, that there might have been slight language gap, but point of the question was probably in terms of "how can I power my Adruino from mains cables dangling from the ceiling going to my ceiling lamp".

Buy a replacement extension cord socket end, attach it to the dangling wires (which are generally a *bad* thing to have about anyway!), and plug a cell phone charger into that socket

MarkT

Good grief!

         -  well it might - I haven't flogged through the sums.. and it would be terribly inefficient even if it did.  If ( a quick glance ) it needed to supply 300mA, your resistors would be dissipating 80 + watts to deliver only 1.5 watts into the 5v load!

BUT it means there's live mains all over the place, with serious safety issues.


Please buy for a couple of quid/euros etc  a  standard plug-mounted device from ebay or any hobby shop.

Be sure to get a regulated one.

regards

Allan
Having seen the inside of an unbranded wall-wart that came with an expensive small monitor recently,
I would advise against ever using any mains power supply from eBay unless you have destructively
examined it for safety...  You literally risk death with these cheap PSUs.

My supply had only the enamel on the enamelled copper wire separating 240V mains from the low
voltage side in the (tiny) transformer.  The interwinding insulation didn't quite reach the edge of
the primary, and was inadequate thickness anyway. Shocking.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

LiborVojtek

Absolutely, they look something like this.
I honestly never saw such a small adapter, it might be the solution after getting rid of those pesky plug sticks. ;-)
Buy a replacement extension cord socket end, attach it to the dangling wires (which are generally a *bad* thing to have about anyway!), and plug a cell phone charger into that socket
Well, the problem is, that I want that ceiling lamp, too. So a socket and phone charger would not do and also I want to pack everything under the round cover of that lamp (10x4cm).
(The cables are not actually dangling around, they are currently connected to said lamp. ;-) )

LiborVojtek

Yes, go to a certified electrician and ask him what can be done, and do not do that yourself, besides that the quality of the DC may be lacking, you may cause a fire in your house or kill yourself. And even if it costs a couple of hundred €, your life is still worth more.
I have intermediate understanding of electricity so killing myself is quite unlikely.
(Always turn off Your breakers before You start sticking screwdrivers to cables.)

Also fire should not be a great risk as there would not be so much of flammable stuff around.
(Always turn on Your breakers after You stop sticking screwdrivers to cables.)

Also also couple hundred € for essentially USB charger adapter is quite high.
(Never allow a car dealer or car mechanic talk You to something You do not want or need.)

Grumpy_Mike

Quote
I have intermediate understanding of electricity
I don't think so. Those things are an elementary understanding at best.

LiborVojtek

I don't think so. Those things are an elementary understanding at best.
At the one hand, I do not think, that product awareness is part of understanding of something.
At the other hand, I do not think that there is so much to electricity other than VIR and PIV.

Nevertheless, BJHenrys answer probably concludes my question with a small problem of Australia been quite few kilometers out of reach for me. ;-)
So I will have to find some other seller.

BJHenry

Sure, that was just an example. You should be able to find that sort of thing in whatever country you're in.

dochawk

(The cables are not actually dangling around, they are currently connected to said lamp. ;-) )
It just occurred to me . . . there are socket extenders for lamps that screw in, have an AC outlet on their side, and then provide a bulb socket.

I haven't seen one in years, but that could be a clean solution.

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