A small simple circuit to get 5 volts from 230 volts mains.

Thread Starter

simmi

Joined Dec 29, 2009
8
Hi.
Summer is approaching and my fan has finally been taken out from its resting place. Which reminded me that I have always wanted to make it wireless.
It runs from the mains so it uses 230 volts.

I would like to know if there is a simple way to get 5 volts from the mains 230 volts to power the peripherals I need to make it wireless. This would most likely be an Arduino chip connected to a Bluetooth module. So I would require 5 volts and something like 100mA making 0.5W.

Smallest and least complicated design wins! :D

Cheers!
 

KMoffett

Joined Dec 19, 2007
2,918
Not only cheap, but free. Check with your friends. They probably have some laying around in a junk drawer. I get mine from a thrift store for $0.75US...5VDC/2.0A

Ken
 

WBahn

Joined Mar 31, 2012
29,976
I agree -- a wallwart is definitely the least complicated (from your perspective) and almost certainly the cheapest. It may or may not be the smallest, but they aren't very big so it should be small enough.

Do NOT build a transformerless power supply if you run across the design for one. My guess is that you probably lack the experience to work with these circuits safely and you don't want to go poking around your 5 V circuitry only to find yourself tangled up with 230 VAC.
 

Thread Starter

simmi

Joined Dec 29, 2009
8
When you say "wall mart" I assume you mean an already produced power supply that is plugged into a wall socket and provides a different voltage. In this case 5 volts.
If so, then that is exactly what I am trying to avoid.
I would like the electronics to be inside the fan's casing.

I agree with you that that is the easiest solution though. But not what I want. Unless it is small enough to fit inside the fan housing and I can "plug it in" the mains inside the housing. Hmm. I have not thought of that before :) Might be viable if I find a super small power supply.
 

WBahn

Joined Mar 31, 2012
29,976
Depending on how much room you have inside the casing, you may very well be able to put the body of the wallwart inside it. You probably want a corded unit so that you can cut the cord and splice it into the fan's cord. Be sure to take into account any polarization of the cord when you do so.
 

#12

Joined Nov 30, 2010
18,224
We see a lot of this. It sounds something like, "I saw one, therefore I must have the education, skills, and test instruments required to build them better, faster, and cheaper." Sorry, pal. Those days are over.
In 1950, anything a man could build, a man could fix. It just isn't true now. There are thousands of things so far advanced that you could pick any 5 and the smartest person you can find couldn't repair most of them. High frequency power supplies are an excellent example of turning me into a dinosaur. I can still do bloody wonderful things with an analog power supply design, but out-classing a high speed switcher isn't one of them.
 

AnalogKid

Joined Aug 1, 2013
10,986
I agree with you that that is the easiest solution though. But not what I want. Unless it is small enough to fit inside the fan housing and I can "plug it in" the mains inside the housing. Hmm. I have not thought of that before :) Might be viable if I find a super small power supply.
That was going to be my suggestion. An iphone charger clone is small and cheap. If you don't have room for the receptacle end of an extension cord, solder the line cord wires directly to the AC plug pins. Important: cover the connections with shrink tubing, preferably two layers of it on each pin. This is what I travel with instead of a USB male-female extension cable. 10 feet long, can reach far-away airport wall outlets, cost pennies. Geek travelers envy me.

ak
 

KMoffett

Joined Dec 19, 2007
2,918
I gut wall warts frequently. The only problem I have is how to mount them. Components are mounted to the very edges of the PCBs. You have to be creative. ;)

Ken
 

Picbuster

Joined Dec 2, 2013
1,047
Hi.
Summer is approaching and my fan has finally been taken out from its resting place. Which reminded me that I have always wanted to make it wireless.
It runs from the mains so it uses 230 volts.

I would like to know if there is a simple way to get 5 volts from the mains 230 volts to power the peripherals I need to make it wireless. This would most likely be an Arduino chip connected to a Bluetooth module. So I would require 5 volts and something like 100mA making 0.5W.

Smallest and least complicated design wins! :D

Cheers!
One chip, plus some low cost components , is doing this. Its the lnk304gn.
However no mains separation so be careful.
Picbuster
 

tracecom

Joined Apr 16, 2010
3,944
In addition to being against the TOS, an lnk304gn, 6 resistors, 5 diodes, 1 inductor, 6 capacitors, and 2 transistors plus a PCB isn't a simple power supply by my definition.
 
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