230V power supply to Arduino

[tbowmo]

What is the efficiency of these "cheap" mains -> 12V/5V converters?

Also, it means that you need a second regulator (be that a linear, or a switching) from 12/5V -> 3.3V.

If you KNOW what you are doing, you could use SR036 from supertex, that can deliver 3.3V directly from mains (non isolated output).

it could probably be used for mysensor connected dimers / light switches on mains. (something where human interface is not needed).

Again, ONLY if you realy know what you are messing with

[axillent]

@tbowmo said:

What is the efficiency of these "cheap" mains -> 12V/5V converters?

they are quite efficient. 5V version can deliver 400mA while unloaded supply consumes only 0.2W

Also, it means that you need a second regulator (be that a linear, or a switching) from 12/5V -> 3.3V.

output voltage is defined by output resistor divider. I have an experience on changing 12V output to 5V by replacing a single SMD resistor. Theoretically the same way you can get 3.3V directly from the supply.

If you KNOW what you are doing, you could use SR036 from supertex, that can deliver 3.3V directly from mains (non isolated output).

it could probably be used for mysensor connected dimers / light switches on mains. (something where human interface is not needed).

that is true. I have the experience with SR036 (SR037 provides 5V output) and can say that you will never find smaller supply. But the output current will not exceed 50mA and this will depends on your mosfet output capability. Such a supply consumes about 1W while unloaded. Etc. not that green from the power consumption. This is my one side SR037 supply:

if you know what you are doing it is also other choice - linkswitch chips LNK302/304/306. The last one can deliver up to 350mA not isolated power directly 5V or 3.3V. It is as efficient as isolated - unloaded it will consume about 0.2W. A bit bigger than SR036. Easy to construct because you do not need custom transformers. For example Duwi zwave wall switches are using this type of the supply. This is my one side SMD version with regulated output:

next one is a classical low frequency transformer. The smallest here http://www.hahn-trafo.com/english/pcb-transformers-bv20.php - BV 201 0128 is ideal to power low power arduino device. It will consume unloaded about 1W. Can deliver about 60mA with linear regulator or about 100mA back regulated at 3.3V output. This one is my light controlling arduino using BV 201 0128:

and the last one is capacitive supply. Most chinice cheap devices are using this type, most cheap supply:

[tbowmo]

@axillent said:

that is true. I have the experience with SR036 (SR037 provides 5V output) and can say that you will never find smaller supply. But the output current will not exceed 50mA and this will depends on your mosfet output capability. Such a supply consumes about 1W while unloaded. Etc. not that green from the power consumption. This is my one side SR037 supply:

I just took a quick google, where the SR036 showed up, so no in depth analysis of alternatives.

if you know what you are doing it is also other choice - linkswitch chips LNK302/304/306. The last one can deliver up to 350mA not isolated power directly 5V or 3.3V. It is as efficient as isolated - unloaded it will consume about 0.2W. A bit bigger than SR036. Easy to construct because you do not need custom transformers. For example Duwi zwave wall switches are using this type of the supply. This is my one side SMD version with regulated output:

That one seems very interesting, for powering arduino things (from an efficiency point of view).

Only one problem, I don't have the time for it at the moment.. I have to restrict my self, in starting new projects :). So for the moment it's battery powered sensors, that are getting my attention,

[axillent]

@tbowmo said:

I just took a quick google, where the SR036 showed up, so no in depth analysis of alternatives.

SR036/037 is very hard to purchase. Even ebay/ali you will find very limited proposal.
It seams that Supertex has stopped a production

[jocke4u]

@Hausner said:

I have with succes used these:

http://www.aliexpress.com/item/Travel-Convenient-EU-Plug-Wall-USB-Charger-Adapter-For-Samsung-Galaxy-S5-S4-S3-Note-3/32220133044.html

They are really easy to dismatle, and the result is this - https://www.dropbox.com/s/ep43uyve5v0msv6/20141206_214210.jpg?dl=0

At $1.10 I didn't even think about making my own PSU

Yes, that is an option. I did it with one and it was pretty easy.

Also found this https://github.com/openhardwarelabs/arduino-power-supply and I like some parts being isolated/encapsulated .

https://raw.githubusercontent.com/openhardwarelabs/arduino-power-supply/master/pictures/IMG_8030.jpg

[axillent]

@jocke4u said:

Also found this https://github.com/openhardwarelabs/arduino-power-supply and I like some parts being isolated/encapsulated .

myrra also provides regulated modules without need of external regulator
for example this one http://ru.farnell.com/myrra/47121/power-supply-3-3v-2-5w/dp/1825772

[RJ_Make]

What kind of protections are embedded?

[RJ_Make]

Never mind...
http://www.farnell.com/datasheets/606238.pdf

[klim]

SR036/SR037 are discontinued products.
Take a look at supertex (microchip) SR086 (Fixed 3.3V) or SR087 (Fixed 5V) or SR10 instead.

[axillent]

thanks for the reference. interesting chip even it requires more external parts than sr036/037
sr036 is still possible to purchase from China
sr086 is available only in brand stores like farnel

[klim]

Here i found a size example of that chips:
power supply

SR086, SR087 and SR10 you can get at ali too.

[axillent]

very cool picture! easy to imagine
SR10 the most interesting for low power
do you have any links to aliexpress?
I'm not able to find any new chips

[klim]

Hi, sorry not available at aliexpress anymore, maybe it was just temporary.
But the SR10 (fqn is SR10LG-G) is available at RS-Components and Alibaba.

Powering the mcu and some peripherals is ok, but do you know the maximum burst time of the NRF24l01 when sending? As all of the chips are limited in current by a few mA, i'm not shure if it will work reliable. I know that big capacitors can fix such issues, but is it sufficient?

[axillent]

All is fine) I found them at local seller
Will be cool to try

NRF24L01 + MCU needs 15mA
If you have other things to connect you need to count them too
for example SSR needs at least +10mA

I'm currently looking for a small supply for the wall switch build based on arduino.
So, I will need 15 + 10 = 25mA. Both SR086 and SR10LG can be sufficient,
SR10LG datasheet has very clear table - power ability is very depends on input capacitor.
25mA should be not a problem. For 240V you need 0.68uF with full rectifier schema
For 120V you will need at minimum 1uF with full rectifier schema

[axillent]

@Hausner said:

I have with succes used these:

http://www.aliexpress.com/item/Travel-Convenient-EU-Plug-Wall-USB-Charger-Adapter-For-Samsung-Galaxy-S5-S4-S3-Note-3/32220133044.html

They are really easy to dismatle, and the result is this - https://www.dropbox.com/s/ep43uyve5v0msv6/20141206_214210.jpg?dl=0

At $1.10 I didn't even think about making my own PSU

Just got it today and made some tests. Price is cool, but I will not recommend to use this for loads higher than 500mA and also will not recommend to supply arduino without an additional 1000uF capacitor. It is a conclusion from the measurement:

• without load 5.34V output with 440mV pulsation, 0.1W consuption
• 10 Om load gives 470mA current 4.74V output with 440mV pulsation, 3.5W consuption
• 5 Om load gives 848mA current 4.43V output with 520mV pulsation, 6W consuption
• 3.33 Om load gives 1.06mA current 4.07V output with 880mV pulsation, 7.4W consuption

[tbowmo]

@axillent

What if you place a 3v3 ldo at the 5V output, what is the ripple then, at the different loads?

[axillent]

@tbowmo said:

What if you place a 3v3 ldo at the 5V output, what is the ripple then, at the different loads?

with good ldo supported by sufficient capacitors it can be fine for arduino
but still I will not recommend to go above 500mA with this supply

[tbowmo]

@axillent

500mA should also be sufficient for a sensor node, even with a couple of relays, mysensors in GW mode, etc. it's not even near the 500mA limit

[axillent]

sure. sensornode without relays requires 15-20mA
with SSR relay will need +10-15mA for each relay
+50-100mA for each regular relay

[Tibus]

Hello, I'm also searching a way to get 5V from AC to make a beatiful mysensor wallPlug... I'm searching the smallest and cheapest way to do it. My problem is I want to drive a regular relay (a SSR is not very good for plug and other things no?), an atmega328 tqfp, a NRF24 and some other things like a current sensor,... so, I think I need 150ma +-? (100ma for the relay, max 25-30ma for the NRF and arduino and some ma for the status leds,...)

I found here the SR086 but I don't know if I could take 150ma on it.
What is the best way for my projet?

I also found these one but don't know if it ok too :
http://www.newark.com/vigortronix/vtx-214-001-105/ac-dc-conv-fixed-1-o-p-1w-5v/dp/45X5484?ost=VTX-214-001-105

I'm searchin the smallest way because i also would like to make a in wall module for interuptor,... so the VTX above is ok for a wallplug but a bit big for a in wall module... How the cubino for exemple make a DC module so small?

[axillent]

@Tibus your selection is fine. Any one above is also fine

what is you worry?

[Tibus]

@axillent My worry is taking 150ma out of a SR086? Is the SR086 ok to give 150ma?

The VTX is ok but big for an inwall module so is there a good way to get 150ma in 5V from 220VAC in the smallest form factor possible? (or in less than 1cm height?)

I also found these one but a SR086 would be fine for a inwall relay... (but 150ma?)

http://fr.rs-online.com/web/p/alimentations-a-decoupage-integrables/7719379/

[axillent]

@Tibus SR086 able to provide 100mA from 9-50V. For example you can set it to provide 20V and add DC-DC step-down for example based on MP2359. This will give you current-UP benefit at 5V etc. 20V@100mA will give you 5V@360mA maximum with 90% efficiency

My preference in your case LNK306, you can get directly up to 350mA. Using ceramic capacitors and SMD inductors you will fit in 7-10mm height (see one of my picture above)

And at last. Why not SSR? What type of the load do you have?

[Tibus]

@axillent Thank's verry much. I didn't know the current up benefit of a step-down. I think it's the key of my problem!
I'll test the lnk306. Hope It will work for my project.

For my "in wall module", it's just lights so no problem for an SSR. But for the wall plug, The user chose the load they want... so if it's a TV or a washing machine or a power supply, I read an SSR is not verry good for these things...

[axillent]

@Tibus YAW
For LNK take a look for AN37, especially optimization at table 9
an37-linkswitch.pdf

SSR is fine for most of the loads. But you need to follow recommendation of their use and to control limitations (like maximum ratings and heat dissipation)

[axillent]

I'm expecting to receive my SR086 and SR10 this week
I have a plan to run some tests

[klim]

Regarding the SR10 i've already here a few, but just no time to build up something ;-(
The more i'm curious for your results.

[axillent]

@klim I made a test PCB

I succeed to get about 34mA with 1uF capacitor and probably it will provide 40mA stated in the datasheet
it is not possible to use it directly without an additional LDO or step-down because of a very high ripple.
According to my measurement ripple is 2.8V with 12.6V average output (figures in table should be multiplied by 10):

consumed power from AC is 0.8 W with 36mA output
this means 57% efficiency, not bad for such thing

[Tibus]

hox much current could you get with a LDO ort step-Down to 5V or 3.3V? 80ma?

[axillent]

@Tibus the output current from SR10 is depends on the capacitor and rectifier. See the table inside the datasheet

with step-down I can get from my prototype about 100mA at 3.3V
with LDO you will get out as many as you get in minus quiescent current of LDO itself

[axillent]

I made a success by replacing polymer capacitor by ceramic one in the usage of SR10
it leads to a dramatical decrease in needed space. I believe that it will be the smallest AC-DC fotprint

But still I have som problems with DHT sensor to work from SR10 (http://forum.mysensors.org/topic/971/small-wall-outlet-sensor-node)

[jeylites]

@axillent

I like the case you are using. Where did you get it from?

[marceltrapman]

@jeylites said:

@axillent

I like the case you are using. Where did you get it from?

It looks like it was printed.

If so, are you willing to share the files?

[axillent]

yes, all cases are printed
sure, I can share if you need
the case developed for a particular custom made PCB

[marceltrapman]

@axillent said:

the case developed for a particular custom made PCB

I understand but the design is still a good starting point

[axillent]

@marceltrapman sure, just give me some time to publish it on thingerverse

[marceltrapman]

Nice, thanks...

[Magiske]

Was looking into the same and ordered 2 different 230/110v to 5v of ebay to get a cheap 5v powersource. Just got them today.

The White around $1.5 and the Black was $1.0

Before wirering everything up, I just added the smaller white's pcb to the black case incl. radio and pro mini. And there is room for a bit more.
So unless it goes up in flames I will try to create a default sensor node.

[Vladut Grecu]

If you don`t go over 50-60% of the amps that that charger can output, there will be no problems. I suggest you replace the capacitor on the 5V area with a bigger one and change the 220/110v capacitor with a higher quality one. What I figure from your pictures is that the black charger doesn't have a bridge rectifier.. It's safer for you to use one. (Don't forget about the fuse)

[ferpando]

Anyone tested one of these cheap power supplies with an osciloscope?
I got a couple yesterday but not sure if they are good enough

[gadu]

I've seen these and also got interested. Any input on these is appreciated.

[Jan Gatzke]

@Magiske I am using a power supply similar to the black one. My one has a fake optocoupler. The output voltage is unregulated. Have a close look before using this pcb.

[Roberto Brunialti]

May be too big or too expansive... but it is for sure a good (and safe...) product with a 33x22 mm footprint..

http://www.mouser.com/ProductDetail/RECOM-Power/RAC01-33SC/?qs=waQl70lBfV2Z5QQrs%2FIAaw%3D%3D

[Jan Gatzke]

Does it fit on 2.54 mm prototype boards?

[Didi]

Yes it does.
Look data sheet http://www.mouser.com/ds/2/468/RAC01_02-SC-16262.pdf

[Roberto Brunialti]

I've got a couple of them (3.3 and 5 V models), the wired models. Just received. Still to test...

[scalz]

you can disassemble some components like transformer and cap. So you can make your own mysensors design and you get very small and cheap transformer. I can't find cheaper I think. or maybe on alibaba!
I have these http://fr.aliexpress.com/item/AC-220V-DC-3V-10V-5V-9V-1w-1x1w-2w-2x1w-3w-3x1w-Constant-Current-Constant/1900256299.html?recommendVersion=1

[msebbe]

@scalz said:

you can disassemble some components like transformer and cap. So you can make your own mysensors design and you get very small and cheap transformer. I can't find cheaper I think. or maybe on alibaba!
I have these http://fr.aliexpress.com/item/AC-220V-DC-3V-10V-5V-9V-1w-1x1w-2w-2x1w-3w-3x1w-Constant-Current-Constant/1900256299.html?recommendVersion=1

Can this convert 230v to 5v and supply enough power for say an pro mini with motion sensor?

[scalz]

@msebbe : yes it can.

[Moshe Livne]

@scalz these are constant current. how come they supply constant voltage?

[scalz]

@Moshe Livne: when I tested it, it was with atmel standalone. So I added a voltage regulator. And you can add a little filter if you want..

[Moshe Livne]

@scalz Oh I see. Thanks!

[axillent]

@scalz said:

I have these http://fr.aliexpress.com/item/AC-220V-DC-3V-10V-5V-9V-1w-1x1w-2w-2x1w-3w-3x1w-Constant-Current-Constant/1900256299.html?recommendVersion=1

I'm using similar one, it is also called 3 x1 W Led driver and by my measurements provides 300mA and 17V without load

I use 220uF to filter its output and I use 78L05 to regulate down to 5V. This can give up to 5V@40mA output. The restriction is a heating desipation rating for 78L05.
For higher loads I would recomment to use DC stepdown. With DC stepdown you can get up to 5V@650mA with 80% efficiency

[scalz]

Sorry for my imprecision. So I agree with @axillent . If it is just for a motion, it should do the trick. But for higher loads, you should add a dc dc step down or use a better thing.

[themoloch]

@axillent said:

if you know what you are doing it is also other choice - linkswitch chips LNK302/304/306. The last one can deliver up to 350mA not isolated power directly 5V or 3.3V. It is as efficient as isolated - unloaded it will consume about 0.2W. A bit bigger than SR036. Easy to construct because you do not need custom transformers. For example Duwi zwave wall switches are using this type of the supply. This is my one side SMD version with regulated output:

Hello axillent, I just bought some of those LNK306 and would like to make a test board, could you share your schematic or components you used to make your own?

Thanks a lot.

[axillent]

@themoloch sure
I'm using a standard schematic from the datasheet. It is also a separate application note exists with recommendation on how to optimize input filter for low loads. The board on the picture for example uses 2x1uF + 2x1uF + 1mH as input filter

[Stefan Schreiter]

@themoloch said:

@axillent said:

if you know what you are doing it is also other choice - linkswitch chips LNK302/304/306. The last one can deliver up to 350mA not isolated power directly 5V or 3.3V. It is as efficient as isolated - unloaded it will consume about 0.2W. A bit bigger than SR036. Easy to construct because you do not need custom transformers. For example Duwi zwave wall switches are using this type of the supply. This is my one side SMD version with regulated output:

Hello axillent, I just bought some of those LNK306 and would like to make a test board, could you share your schematic or components you used to make your own?

Thanks a lot.

Can you give me please the schematic and BOM of your LNK Circuit?

[ahmedadelhosni]

@axillent Hello. It is an old topic but I am really interedting in your designs and want to know how stable are they after 1 year.

I have two question please.

• I am desiging the LNK pcb layout but I am a bit confused regarding safety. Pad size ? Trace width ? Ground plane for heat sink ? All these stuff. You mind sharing your design please ?
  Also I dont see a fuze or MOV in your design. Aren't they important ?

• you posted above 4 circuit deaigns. regarding the final chinese cheap design, what are the advantages and disadvantages of that design. I have just saw it in a cheap LED lamp.

Thanks.

[diegolf]

@axillent
Hello my friend! Can you share the schematic and BOM of this LNK circuit, please? I tried to follow LNK Datasheet, but is different of your Project...

thx

[Stephan]

Hello, I return to this topic which dates a bit.
I am very interested in the version that uses the LNK306.
I found this electronic diagram that uses LNK306

Could you provide a detailed nomenclature?
Thank you in advance.

Best regards.

[croc]

@themoloch Hello can you please tell me which 1uf you bought? because you have them in parallel and what is the maximum Am you can get out of them. regards from croc.

[croc]

@axillent can you look at my early question? can you send a BOM list from your design?

[axillent]

@croc sorry to be so late in answer
this as an application note 0_1479681329040_an37-linkswitch.pdf
My design is equal to the schematic posted by @Stephan except an input filter. According to an37 I'm using 2uF + 1uH +2uF as input filter.
I'm using a compact X7R 1uF x 450V purchased from aliexpress. Instead of RF1 I'm using PTFE (a resettable fuse) 40mA @ 250V
D3 + D4 are M7
D1 is US1J / ES1J
C2 & C3 are also X7R

[croc]

@axillent thanks and what is the smd coil that you use?