NO FCC rf link?

Of course there is.Use light, IR or even just a red led, to transmit.

On a sunny day (Fri, 12 Feb 2021 18:54:38 +0100) it happened Sjouke Burry wrote in :

Or ultra sound, old remotes worked that way.

Or use ultrasound , 100khz should allow datatransmission.

You just beat me with that. :)

There are lots of unlicensed frequency bands.

google fcc unlicensed frequency bands

and there is

and at low power you are unlikely to get caught anyhow. It's the Wild West out there now.

That's how my thermometer for beer brewing works. Reads the temp in the basement or yard and relays it up here so I can work, and alerts me if a target is almost reached. I have a ham radio license but it does not use ham bands because that would be illegal.

Key is to use gear that already has all the agency blessings for ISM use and then _not_ modify antennas and the like because that can invalidate an approval. For the op's job that should be really easy because of low range and it's just one simple function. Best is to simply buy a set of devices.

Out here in the hills of California it always was, since almost 200 years. In Placervile (a.k.a. Hangtown) justice wasn't always just but quick. They still make sure people know:

These are CPLDs, so you'll need to develop a firmware for them, unless you can find a third party firmware that does what you want.

Well typical of this forum, my question gets lost. I said RF..... right? Not infrared etc.

Thanks John -- didn't see your reply.

But really if it has (any) xmtr is has to be fcc approved period, right?

Life used to be so cheap, death so everyday.

My SA is set up; I was just looking for spurs on a TI synthesizer chip.

I can bandpass filter out the far-out spur. The harmonics don't matter in a digital system.

I hung a banana lead on the SA input. It's the Wild West. There must be thousands of RF signals zinging around my office these days.

A lot of our security sensors and such are wireless. There's wifi, microwaves, doorbells, dishes, car fobs, cell phones, drones, bluetooth, light bulbs, so many RF devices, the majority with fake FCC/CE stickers. The FCC would need a million trucks to snoop out all the violations.

I'm impressed that it all mostly works.

Bluetooth and WiFi is RF :-)

What I had in mind was simple and cheaper but whatever you buy, make sure it has the approvals for the US (or country you want to use it in):

There are also some without rolling codes.

If you need something to switch mains you can usually buy that at a local big box hardare store (RF-switchable outlet).

Legally that is called "intentional radiator" and just as most stuff has to comply with FCC rules. You can buy a complete keyfob transmitter with approval, matching the receive side.

Even commercial users who integrate something like that into an end product typically go the "pre-approved module" route because it saves them a ton of paperwork and legal exposure.

are there any pre-approved modules dirt cheap that aren't in a case but just on pcb? like I say, I just need an on/off command

Yes, for example:

Also lots on Ebay for even less money. However, as I said you have to do your due diligence to find out if they are truly pre-approved. There are a lot of fakes out there.

Whenever I integrated RF pre-approved modules for clients I first demanded the paperwork, to make sure. Just like with power supplies whetre I wanted to see the UL test report from a reputable test house.

But signals from Telegraph Hill should be much less pronounced at your new place.

Often it doesn't. My ham radio fun is greatly crimped by solar roofs. A lot of inverters are s***ty and maybe their EMC ratings are fake.

r to just get a basic on/off command without FCC approval right? Just a dam n rf link for 20 feet that doesn't require sending it to a lab etc and woul d be perfectly legal in a small volume product? Isn't there some sort of li cense free band or something? I always get so pissed whenever I want to do this but I always hit a brick wall. -- thanks

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MUCH thanks.

Sutro Tower. No, it's about the same distance, 2.5 miles, and this is a wooden building too. The tower is in plain sight from the roof.

Why do we still have big transmitters? Car radios maybe.

Certainly fake.

Being mostly retired I do not have long drives to clients or airports much anymore but I thoroughly enjoy AM radio in the car. In Europe they shut most of that down, at least in Germany. IMO a big mistake because when you have a major disaster that (and ham radio) is all you've got left.

Yeah, but calling the goons on them would not exactly keep the neighborly friendship up.