Layers

Other Hardware General Electronics
1

Ddoes anyone know how many layers there are on the uno board please

2

2

3

Thank you, do you happen to know if any of the mini pros are ce compliant ?

4

I'm going to go with no, as I imagine no one has paid the money to do the testing.

That being said, CE compliance is usually from a self contained unit, and an arduino is not exactly self contained, as on its own it doesn't do much. So asking if an individual board is CE compliant is not all that useful. What you really need to determine is if your final product is CE compliant.

5

Boardburner2:
Thank you, do you happen to know if any of the mini pros are ce compliant ?

No need, there's nothing dangerous about them. It's just a Mega328 on a board, it doesn't have a mains plug.

6

Thanks , that makes sense, id noticed that my arduino is both CE and FCC lablled

7

Did they release any official documentation on what they did for CE Certification? I know what is required if it connects to mains, but one of the other concerns is ESD, and I'd be surprised if the board is ESD proof.

8

This is the crux of my problem.
To have CE mark it has to comply with unintentional emission criterea.
I have seen no documentation though.

I have to design a board and have it tested.
I suspect this will require a 4 layer board though.

9

This seems to belie the claim.

10

Be sure to share your "improved EMI" PCB design under the "share alike" clause of the Creative Commons license...
(I guess you won't have to if you don't look at the current design?)

11

I would have no problem with that.

I was hoping that as its fcc marked i could just crib the current design.
Iv been told that its highly unlikely a 2 layer board would meet unintentional radiation criterea though.

Unknown waters for me.

4 layers is costly, shielded enclosure would probably be cheaper.

12

4 layers, yes, about 5 times as much if iteadstudio 2 layer 10cm x 10cm vs 4 layer is a good indicator: http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html?p=2
$19.90 for 10 PCBs vs $99 for 10 PCBs.

13

its highly unlikely a 2 layer board would meet unintentional radiation criterea though

I'm not convinced. There are a lot of 2-lay boards out there (though usually in cases.) Wasn't the EDN article talking about conducted emissions through the cables, and the (cheap) wall wart?

14

I am going to take one to a radio ham mate tonight and see what i can measure.

15

Ok
The rfid reader showed intentional emissions within limits , that was the addafruit shield.

Arduino on its own showed a big spike at 64 MHz out of unintentional limits when powered from battery on a short lead.

For comparison a rasbery pi showed a wideband hump at roughly the same frequency which was in limits.

I had hoped to post photos but they have got mangled in email somehow.

I hope to do more quantitative measurments sometime with better equipment.

I used a tv dongle type spectrum analyser which only goes down to 20 MHz.
Aerial was wrong and in a very noisy environment.

16

I hadn't thought of using one of those SDR things as a RF emissions test tool. Neat idea! (Is there a how-to anywhere?)

I wonder if the 64MHz spike is coming from the 16u2 or the 328? (or both?) You might be able to test by grounding the RESET pin, which should leave the 328 reset (and not running its oscillator at all), and only the 16u2 running.

17

The software was developed by the radio ham community , as was the hardware.
You have to get the right make of dongle though.
A search should find it.
Its quite impressive.

I believe the 64 mhz is a harmonic of the crystal, there are others but that is the largest.

bump.rtf (3.77 MB)

18

pic now uploaded