Ultra minature power supply (250Vac -> 5Vdc/250mA) from the mains?

Other Hardware General Electronics
1

I've been working on a little project with ATTiny controlling a relay and using ESP8266 for communication.
I want to power it from the mains, so I never have to touch it again.

It needs to be tiny, so I can put it inside of the existing mains socket in the wall.

ESP8266 and ATTiny are super compact. I found a ultra-miniature relay which is small, but the power supply is causing the issue.

I looked up few SMPS's which could do the job and they are fairly small 30x25x20mm but it seems not small enough... ie.

Are there any smaller power supplies?

Here is what I need:
Input - 250V
Output - 5V / 250mA ~ 1.25W
Dimensions - smaller than 30x25x20 mm

I need something small and I don't think I am good enough with electronics to build my own SMPS.
Are there any alternatives for powering electronics?

Peter

2

Not as much fun as building one, but they come ready made and certified in different styles to suit your country
https://www.google.co.uk/search?q=electrical+socket+with+usb+port&rlz=1C5CHFA_enGB531GB531&espv=2&biw=1022&bih=489&tbm=isch&imgil=216nhLXGsVB5TM%253A%253Bwcm7sGqVFTcE2M%253Bhttp%25253A%25252F%25252Fgigliwood.com%25252Fblog%25252Fusb-power-ac-wall-outlets.html&source=iu&pf=m&fir=216nhLXGsVB5TM%253A%252Cwcm7sGqVFTcE2M%252C_&usg=__mh14-oqtuEnKp51uDpvYambUHxE%3D&ved=0CFwQyjc&ei=BBHrVPDbIZTzarf7gagG#imgdii=_&imgrc=216nhLXGsVB5TM%253A%3Bwcm7sGqVFTcE2M%3Bhttp%253A%252F%252Fgigliwood.com%252Fblog%252F_Media%252Fusb_charger_outlets_med_hr.jpeg%3Bhttp%253A%252F%252Fgigliwood.com%252Fblog%252Fusb-power-ac-wall-outlets.html%3B562%3B300

3

@Jackrae,
Great link !
I never thought about that but it reminds me of the USB ports in the Aria Casino Hotel rooms. That's probably the perfect item for an arduinoist. (you know, one in every room) Also great for charging your cell phone (if you have the cable handy)

Highest power device on the market
Two vertical high powered USB Ports
3.6A charging capacity

4

Now there is an interesting thought!

How would it be if it was not just a power outlet, but surreptitiously sucked your data? :astonished:

5

Really no different from having your wifi capable PC/laptop/tablet or mobile phone switched on. Are they not capable of being used as similar snooping devices, after all some very clever (and some not so clever) people wrote their operating systems.

6

I appreciate the usb charger as a power source. The thing is I am looking for stand-alone power source so I can use it in other circumstances.

In the meantime I found this:
http://www.powerpax.co.uk/power-supplies/pcb-mounting-power-supplies/1w-to-5w-miniature-pcb-mount-ac-dc-power-supplies/1w-to-3w-miniature-pcb-mount-ac-dc

The question remains:

Is there a tiny 250Vac -> 5V/250mA power source smaller than 34.026.010.5mm.

7

This one is pretty small - 40mm x 40mm x 15mm.
Only supports 120V tho, I use one to charge my smart phone at work.

There's this 250AC to 5VDC/400mA adapter

33.7 mm L x 22.2 mm W x 17.75mm H

200mA unit is a little less tall, 17mm

You can search for similar units and perhaps find one a little thinner.

8

This one is similar size

Ratings seem to be 1W and 2W, you are looking for 1.25W.