Wireless that's "Fall off a log" easy?

Sure. There are complete modules, complete with certs.

Sure. All available. You supply the $$.

Easy. This is a neat one with versions up to 2Mb (RSN?):

We use stuff from RFM/Cirronet. Nice, but rather expensive.

Take a look at the BT modules from Lairdtech:

I've used them for several years now in one of my products. The BT modules are certified and supplied with an extra sticker with all the necessary information. Put that sticker on the outside of your product and it makes that product certified.

Meindert

I havent used this but take a look, UK based.

Cheers

Nordic Semiconductor has a chip coming up any day now, but it's been like that for a while:

I mention it because their 2.4GHz RF chips seem OK, so this might be too, someday.

Mel.

...and you have to be careful that their competitors don't sue you if you use the modules outside of their originally licensed uses. :-)

Well, there is that. ;-) OTOH, I'm quite sure there is a way around the issue for the sufficiently motivated.

Have a look at

I haven't used those modules myself. I've used some of their AM stuff in the past (albeit for experimentation rather than in anger) but that is only good for 2400 baud. This is good for 115200, SPI interface and $7.35 per unit from Digi-key. No Bluetooth though.

You mean this one?

Couldn't find the words FCC or "pre-certified" in there, so be careful. Also, I found that any schemes that aren't frequency-agile are not all that reliable. Especially with rather vulnerable AM protocols.

Just curious... What's the worry about certification? Certifying an intentional radiator costs a little, but not all that much more than certifying an unintentional radiator (containing a certified module). If our lab's interpretation of the (FCC) regs is correct, the intentional radiator covers a *lot* of the sins of the rest of the box. BTW, we don't do this, but it is an interesting kink in the regs.

The FCC has made the process fairly friendly lately but last time the cost was another $5k, AFAIR. Plus you must use a TCB certified lab which may mean a longer drive, and possibly higher fees for the regular EMC job. Some companies just ship the stuff, without one of their engineer witnessing the testing (I strongly discourage clients from doing that).

If you build thousands of units a year it certainly makes sense. Of course, you also have to factor in and amortize your own design work on the RF portions of the project that would otherwise already have been handled by the module vendor. That often gets overlooked.

It costs us about $2K (maybe a little less) to have the scans run for unintentional radiation, assuming it passes the first shot. We had a nasty experience were it took many attempts and several weeks. $5K would have been a bargain. That disaster was at least half the fault of the testing lab, though, so we try to not go there anymore.

It is silly to just ship stuff off to the lab. If anything goes wrong (it always does) there is no one there to fix it. I'm the one who generally goes. I kinda like Atlanta. ;-)

I'm not talking about designing the RF section, rather only the certification part. specifically, whether to use the RF module's certification and then certify your box as an unintentional radiator or certifying the entire box as an intentional radiator.

but

Well, but that's in Jaw-jah, not Taxafornia :-)

That's why I urge clients to send an experienced engineer along _and_ do pre-compliance checks inhouse.

For small qty stuff (meaning not millions/year) it's almost always better to use the module's cert and slap that extra sticker from its mfg onto the client's box. Only one more sticker, next to all the other mandatory ones like "Do not put in mouth" and all that :-)

but

Same companies. The unintentional scans (line and radiated) take about four hours, which translates to $1600 in the 10m chamber (*much* more reliable than a slightly less expensive 3m chamber).

In our case, these were useless. With our equipment I can't even get a decent sniff.

But the module's cert doesn't certify the whole box, unless there isn't anything else in the box.

at

our

but

But then all the high ones need to be worked of out in the range, mostly using a receiver. Which adds hours. That's why the winter rule is BYOJ (bring your own jacket) :-)

Mostly I just use a computer-controlled scanner. If there is a nasty emission somewhere it'll find it. Sure, I can't quantify it here in the lab but after a couple of decades on the beat you know what'll cause problems, just like an older cop can look a guy in the eyes and tell that "he dunnit".

goes.

For the intentional part it usually does, the mfg would tell you that (and supply the cert/sticker). Unless you do some unauthorized mods. The unintentional part needs to be tested just like it is with non-RF gear.

If the mfg waffles on the stickers and cert copies, run.

as

and

at

our

radiator

this, but

I don't follow.

been

Scanner? Does it cover the entire range (30mHz to a few GHz)?

goes.

certification

as

Understood, but my point is that the intentional limits are considerably higher than the unintentional, outside some forbidden zones, so it's far easier to pass. Actually, they're so lax that you'd have to *try* to fail them. ;-)

That's not my point.

easy

OEM

as

and

at

our

radiator

this, but

than

Way this works: You go into the chamber where there is a computerized setup that logs the whole chebang, conducted radiated horizontal/vertical. Out comes a list and then usually there are some close calls. If one or more were way above limits then you pack up and come back after some redesign. If none were above or just vy a smidgen everything gets trundled out to the open space setup. There's a hut with a big fat receiver in there and (hopefully) some hot coffee. The DUT gets placed on a rotary table outside. Now they take the list of close calls and check all those again.

This is because chamber measurements are not very precise.

been

decent

Not 30 millihertz :-)

Goes from close to DC to a little above 3GHz.

goes.

certification

as

It doesn't matter, you still have to pass regular (unintentional) EMC outside your intentional transmit band. That part doesn't get any easier. But why pay the extra chunk of money for field strength measurements on the ISM band or wherever you are transmitting, when you don't have to? That's like paying sales tax for the same item in two states.

Ok. Then why not just slap on the sticker, do only the regular EMC and be done with it? Of course the EMC lab needs to know about the intentional radiator part so they don't flag that.

easy

OEM

as

and

looked at

If our

radiator

this, but

than

Ok...

BTDT.

Hmm. The chamber is the gold standard. A 3M isn't worth much, but we've had no trouble with the 10M. The rotary table and all that jazz is in there.

been

decent

No? ;-)

What sort?

goes.

certification

box as

If you read the regs, at least for FHSS radiators in the ISM bands, anything outside the band, and outside one or two do-not-collect-$200 bands, must only be 20dB down from the in-band radiation. Easy-peasy, when you're radiating a hundred or two milliwatts.

Because the intentional limits are almost impossible to fail. We pass easily, now, so there isn't any point in gaming the system, but the rules leave the door wide open.

BTW, what kind of antennas are you using at 30 milli Hertz ?

Even if 30 MHz .. multiple GHz is intended, getting a sufficient antenna bandwidth is a challenge.

At 30 MHz the wavelength is 10 m, so doing the measurement in the far field requires a big room.

Big ones.

That's the least of the problems.

Or far out in the field.