Most compact method of powering Arduino from wall socket

Question 1

There are a lot of methods to power an Arduino from a large range of voltages:

USB cable from PC or from a phone charger or an USB hub
step down converters
step up converters
switching power supply
batteries (connected to the power jack or USB or to Vin)

What I can't seem to find is a small 220V-5V converter. I'd like to put an Arduino in the wall, under a light switch, so size matters.

The last resort option is to open a 5V phone charger and replace the metal prongs that go in a socket with two wires, and replace the USB socket with another pair of wires that go the Arduino board, but still, an Arduino Pro Mini or an Arduino Nano is smaller than the phone charger.

Question 2

Check your insurance if you are covered in case of fire caused by your construction.

Question 3

@Josef Your comment looks like a question. If you have a new question please post it as such.

Question 4

The last resort option is to open a 5v phone charger and replace the metal prongs that go in a socket with two wires, and replace the usb socket with another pair of wires that go the arduino board, but still, an Arduino Pro Mini or an Arduino Nano is smaller than the phone charger.

You will probably have to do something like that.

Because of the nature of conversion between AC and DC, there has to be some large parts.* I'm not going to go into the specifics here. There is usually a diode bridge (because AC waveforms reverse the current ~60 times a second) and a transformer (to lower the voltage for the diode bridge). They almost always include a regulator and a capacitor to make sure voltage is exact and it outputs a "clean" power supply.

*Switching power supplies, although considerably more expensive, are a lot smaller and more power efficient.

This adapter seems to be the most compact adapter I can find for 220V. You'll never get something near the size you are desiring, even with a switching power supply. I don't know the size of the Amazon adapter I gave a link for, but in the US (120V), iPhone chargers are very small and they should fit in a standard depth outlet box (with a little room left over for relays and such). If you really need to get everything smaller, I recommend using a ATtiny chip.

How I recommend connecting this:

I would avoid ripping this apart at all costs from a safety perspective. It would be really easy to send 220V to your Arduino if you're not careful. If you absolutely have to, you might want to coat it with some non-conductive epoxy or other coding. Note: this may act as a thermal insulator, therefore reducing the lifespan of the part. You should just coil some wire around the prongs, and then melt a little solder onto each of the terminals. Then, cover that with electrical tape and pigtail (with a wire nut) into a source power line. Note: you probably are doing wiring that could be illegal in your area. Check your local building codes before attempting this.

After that, attach a USB cord to the socket and to the Arduino or the ATtiny/ATmega328 chip 5V/GND input (of coarse, after cutting and stripping one end of the USB cord). I would also, after finalizing all the code and circuitry, seal that with some epoxy or somehow add it to an enclosure to make sure you don't fry your Arduino if a loose wire touches the Arduino circuitry.

If you don't feel safe doing any of the above, don't do it. You can live without a Arduino light switch.

That being said, happy hacking! :P

Question 5

I don't think you can get much smaller than this for a mains -> 5V converter that is isolated from the mains. There are tricks to get non-isolated low voltages, but they are not generally safe.

Question 6

Thank you, I will order a few of these adapters and post here with the results.

Question 7

@Vladb If you haven't ordered them already I would suggest asking a question on Amazon for the dimensions. Editing my post to suggest how to connect those to the wiring and your Arduino.

Question 8

@Vlad Updated post.

Question 9

No. This is big because it is a linear power supply where the transformer operates at line frequency and so must by physically larger. It's also unregulated and poorly filtered. Switching power supplies as have largely taken over in the past few years are much smaller, because their transformers are operated at the higher switching frequency.

Question 10

I can suggest you to try this : AC DC Step Down Converter

It is as small as the Apple's tiny cube, and it can be placed inside of a wall easily. (I'm personally using this with an arduino micro)

Question 11

Thank you for the information, i have ordered a few of these too.

Question 12

Im not quite about things that go to the mains from aliexpress. Anyone used that thing?

Question 13

Nowadays, most smartphones come with a charger that is linked to the USB plug of the phone.

The charger for my HTC says: 5V, 1A, I guess this voltage must be regulated (but I haven't checked it has the charger is sealed).

enter image description here

The charger itself has a female USB socket on which you can plug any USB cord to link to your Arduino.

IMPORTANT! I have never tried it myself! I would not bet my life on it! It would be wise to check the output voltage is well regulated.

Question 14

It's regulated. I've cracked those units open to use the circuit inside in other projects. It's amazingly compact.

Question 15

Simplest and cheapest solution...if it's good enough for Samsung et al then it's...

Question 16

I use this one, 5V, 3W, very small, and only 3ドル on Aliexpress. http://www.hlktech.net/product_detail.php?ProId=54

Question 17

Using this, following safety tips at skippy.org.uk/quick-look-at-the-hlk-pm01

Question 18

It's 34mm x 20mm x 15mm, which is very small.

Question 19

The smallest is probably a plug-in USB charger such as Apple's tiny cube. The cheapest is bound to be a ~9v (output) wall-wart scrounged from the lost and found in a tourist's/traveller's hotel.

Question 20

There are small board-mount AC/DC converters like this one http://www.digikey.com/product-detail/en/BP5063-5/BP5063-5-ND/658569

Question 21

The website says it only works for 120VAC, but the OP says they want a 220V adapter. I guess the title is a little misleading... and there might be another model for 220V.

Question 22

true. i don't know how much power OP needs but one of these similar ones might work. digikey.com/product-detail/en/BP5041A5/BP5041A5-ND/658559 , digikey.com/product-detail/en/PBK-3-5/102-3106-ND/4332643 , digikey.com/product-detail/en/PBK-1-5/102-3101-ND/4332638

Question 23

Any good idea is worth investigating. It might be for 110V but now I can look for the 220 version, if there is such a thing. Thank You! DrewTM - you posted right before I did. Thank you again for the links!

Question 24

An obvious answer has been omitted which is: transformerless power supply. If your average power requirements are low (<10mA) then this is the most compact way to achieve the desired voltage.

For an in-depth study see: http://ww1.microchip.com/downloads/en/AppNotes/00954A.pdf

Another solution: jeelabs.org /2011/11/27/ultra-low-power-supply/

Some limitations:

safety - NONE - your circuit might now be floating at line voltage
heat dissipation - calculate here: www. daycounter.com/Circuits/Transformerless-Power-Supplies/Transformerless-Power-Supplies.phtml
low current - no servos or relays
voltage fluctuations on the line might affect the circuit

Question 25

Best answer, much smaller than other options.

Question 26

wanted to do a similar thing and I found and just ordered these:

http://uk.farnell.com/recom-power/rac03-05scr-277/conv-ac-dc-3w-90-305v-in-5v-out/dp/2289701

A fully sealed power supply, disk-shaped, 5cm diameter and 11mm thick. THey are available in 3.3V, 5V, and 12V. They are designed to be put inside walls or behind switches.

Question 27

That's pretty neat. The product is discontinued anyway. Is there a version around that can output 2A instead of 600ma?

Question 28

Try an LED driver. Their typical output is 11.8V DC, which is in perfect specs for the Arduino. You can find them nowadays in all shapes and sizes, round or square, low profile or boxy. A 500ma version (6W) is more than enough for your needs.

Question 29

Try something like this. It's 29x15mm and does 220V AC to 5V/3W DC.

Question 30

This one is 51 x 30 x 17.5mm

Question 31

What if you replace the nearest outlet with some kind of USB Wall Socket and attach to that (either through a standard USB plug, or inside the wall) ?

Question 32

This looks like the smallest and cheapest one from all of the above mentioned: http://www.ebay.co.uk/itm/AC-DC-Power-Supply-Buck-Converter-Step-Down-Module-5V-700mA-for-Arduino-U-/121355318138

Question 33

It would be helpful if you mentioned some of the details of that converter in your answer.

Question 34

Ordered a few of these, will add comment with the results when I get them.

Question 35

Nov 2016 Here is a list of compact PCB mounted power supplies that are small (~50mmx25mmx20mm) from Mouser:

http://www.mouser.com/Power/Power-Supplies/AC-DC-Power-Modules/_/N-dv0g5?Ns=Output+Current-Channel+1%7c0&No=25&P=1yxt7eu

These all take in 120-240VAC and provide outputs in the range of 3 - 5 vdc with varying options for current.

The 5V 1A from Meanwell (IRM-05-5) looks like a good deal at 8ドル.52 each. http://www.mouser.com/ProductDetail/Mean-Well/IRM-05-5/?qs=sGAEpiMZZMuWiaalG5TUgH52QN1%252bIKAVmGC9ENLDVf688EuOMfqROg%3d%3d

Paul.

Question 36

Wow, that's a nice one. Does it have output galvanically isolated from input (i.e. "can I touch the board powered by this thingie")? The datasheet mentions resistance between input and output and also has a couple of coils on schematics, but I'm still not sure.

Question 37

The datasheet quotes "Isolation Class II". See: en.wikipedia.org/wiki/Appliance_classes#Class_II

Question 38

It's entirely dependent on whether or not you want to isolate the circuit from the mains. You could use a drop resistor a rectifier and a 5v zener diode but I do not recommend this if you are a hobbyist, in fact I don't recommend this at all, but it is done by some manufacturers with appropriate circuit protection.

score 8 · Accepted Answer · 2014-03-19 15:55:13Z

The last resort option is to open a 5v phone charger and replace the metal prongs that go in a socket with two wires, and replace the usb socket with another pair of wires that go the arduino board, but still, an Arduino Pro Mini or an Arduino Nano is smaller than the phone charger.

You will probably have to do something like that.

Because of the nature of conversion between AC and DC, there has to be some large parts.* I'm not going to go into the specifics here. There is usually a diode bridge (because AC waveforms reverse the current ~60 times a second) and a transformer (to lower the voltage for the diode bridge). They almost always include a regulator and a capacitor to make sure voltage is exact and it outputs a "clean" power supply.

*Switching power supplies, although considerably more expensive, are a lot smaller and more power efficient.

This adapter seems to be the most compact adapter I can find for 220V. You'll never get something near the size you are desiring, even with a switching power supply. I don't know the size of the Amazon adapter I gave a link for, but in the US (120V), iPhone chargers are very small and they should fit in a standard depth outlet box (with a little room left over for relays and such). If you really need to get everything smaller, I recommend using a ATtiny chip.

How I recommend connecting this:

I would avoid ripping this apart at all costs from a safety perspective. It would be really easy to send 220V to your Arduino if you're not careful. If you absolutely have to, you might want to coat it with some non-conductive epoxy or other coding. Note: this may act as a thermal insulator, therefore reducing the lifespan of the part. You should just coil some wire around the prongs, and then melt a little solder onto each of the terminals. Then, cover that with electrical tape and pigtail (with a wire nut) into a source power line. Note: you probably are doing wiring that could be illegal in your area. Check your local building codes before attempting this.

After that, attach a USB cord to the socket and to the Arduino or the ATtiny/ATmega328 chip 5V/GND input (of coarse, after cutting and stripping one end of the USB cord). I would also, after finalizing all the code and circuitry, seal that with some epoxy or somehow add it to an enclosure to make sure you don't fry your Arduino if a loose wire touches the Arduino circuitry.

If you don't feel safe doing any of the above, don't do it. You can live without a Arduino light switch.

That being said, happy hacking! :P

I don't think you can get much smaller than this for a mains -> 5V converter that is isolated from the mains. There are tricks to get non-isolated low voltages, but they are not generally safe.
Thank you, I will order a few of these adapters and post here with the results.
@Vladb If you haven't ordered them already I would suggest asking a question on Amazon for the dimensions. Editing my post to suggest how to connect those to the wiring and your Arduino.
No. This is big because it is a linear power supply where the transformer operates at line frequency and so must by physically larger. It's also unregulated and poorly filtered. Switching power supplies as have largely taken over in the past few years are much smaller, because their transformers are operated at the higher switching frequency.

Stack Exchange Network

Most compact method of powering Arduino from wall socket

14 Answers 14

If you don't feel safe doing any of the above, don't do it. You can live without a Arduino light switch.

Your Answer

Sign up or log in

Post as a guest

Post as a guest

Linked

Hot Network Questions

Most compact method of powering Arduino from wall socket

14 Answers 14

If you don't feel safe doing any of the above, don't do it. You can live without a Arduino light switch.

Your Answer

Sign up or log in

Post as a guest

Post as a guest

Linked

Related

Hot Network Questions