How to communicate with Raspberry Pi without the Internet?

[Arminas]

Hi, I have raspberry pi, but I want it to be non-wired, but you can contact them and send commands to raspberry pi. Maybe you know how to do this?

(Sry for bad english, google translate)

[B.Goode]

Welcome to the Raspberry Pi forums.

Maybe one of the forum sections in other languages would suit you better? viewforum.php?f=90

I want it to be non-wired

Use Wi-fi. ( Wireless local area network.)

[fruitoftheloom]

Hi, I have raspberry pi, but I want it to be non-wired, but you can contact them and send commands to raspberry pi. Maybe you know how to do this?

(Sry for bad english, google translate)

If you have a RPi ZeroW or 3B you can create an access Point:

https://www.raspberrypi.org/documentati ... s-point.md

[Arminas]

Welcome to the Raspberry Pi forums.

Maybe one of the forum sections in other languages would suit you better? viewforum.php?f=90

I want it to be non-wired

Use Wi-fi. ( Wireless local area network.)

Yes, but the range is only 10-50m.

[B.Goode]

Do you mean you need a solution that works at a greater range? If so, over what distance?

Or do you mean you only need to cover a short distance so you think WiFi is too powerful?

[Heater]

So, if I understand correctly, you want a wireless connection to a Pi with a longer range than 50 or so meters?

Sadly, in most countries there are laws restricting what we can transmit over the radio waves.

As a result we are restricted to WIFI and it's short range.

You could get yourself a Amateur Radio Operators licence and set up some kind of packet radio link. I suspect that is a bigger project than you are looking for.

The longest range wireless devices we can use cheaply and easily are using LoRa. https://www.loriot.io/modems.html but they are generally very low speed connections.

[Arminas]

So, if I understand correctly, you want a wireless connection to a Pi with a longer range than 50 or so meters?

Sadly, in most countries there are laws restricting what we can transmit over the radio waves.

As a result we are restricted to WIFI and it's short range.

You could get yourself a Amateur Radio Operators licence and set up some kind of packet radio link. I suspect that is a bigger project than you are looking for.

The longest range wireless devices we can use cheaply and easily are using LoRa. https://www.loriot.io/modems.html but they are generally very low speed connections.

Is it possible to connect the Xbee module and send commands through it and receive replies from Raspberry Pi?

[Heater]

Certainly. I'm sure you can hook an Xbee to the UART pins on the Pi GPI header and talk to the Linux console that way.

Range won't be much though. Nor very fast.

[broe23]

So, if I understand correctly, you want a wireless connection to a Pi with a longer range than 50 or so meters?

Sadly, in most countries there are laws restricting what we can transmit over the radio waves.

As a result we are restricted to WIFI and it's short range.

You could get yourself a Amateur Radio Operators licence and set up some kind of packet radio link. I suspect that is a bigger project than you are looking for.

The longest range wireless devices we can use cheaply and easily are using LoRa. https://www.loriot.io/modems.html but they are generally very low speed connections.

Is it possible to connect the Xbee module and send commands through it and receive replies from Raspberry Pi?

50 meters do not require a public radio frequency license, such as Ham Radio operators would need. Heeter loves to throw out there the fear that everything is illegal, when there are WISPS out there that backhaul up to 2 miles and have yet to have someone call in to check if they have a license or not, which a WISP would, a homeowner using WiFi on a large property does not need any license of operation, nor is anyone going to know, since the bandwidth of the radios for Wifi are already covered under the same rules as FRS radios.

I can pick up my wifi Access Point up to 200 feet away and have yet to get anything sent to me by the FCC or local governing bodies. That is because the Access Point I use has a strong radio, set for the proper channels needed. I could easily hop the signal all over my town if I wanted and all that I would have to pay for, would be the use of space on tall enough structures.

[asandford]

There are radios that have a range up to 1km with fast serial connections to the Pi, and are licence free in Europe, but it's not cheap.

Another line of research would be LoRa.

[Heater]

broe23,

Heeter loves to throw out there the fear that everything is illegal,...

I presume you mean me. Well, Heater does not love to do any such thing. Please don't misrepresent what I say.

I do from time to time point out that there are laws restricting what we can do with electro-magnetic radiation.

Yes, WIFI is license free. Within limits. Yes one get surprisingly long range from WIFI in some conditions. Nothing illegal about that. But those limits are why we don't have a means of wirelessly communicating over long distances in license free spectrum.

[Ronaldlees]

broe23,

Heeter loves to throw out there the fear that everything is illegal,...

I presume you mean me. Well, Heater does not love to do any such thing. Please don't misrepresent what I say.

I do from time to time point out that there are laws restricting what we can do with electro-magnetic radiation.

Yes, WIFI is license free. Within limits. Yes one get surprisingly long range from WIFI in some conditions. Nothing illegal about that. But those limits are why we don't have a means of wirelessly communicating over long distances in license free spectrum.

Exactly. If WiFi were very powerful, it would be usable by far fewer people within each unit of area. The idea was to make it usable within the scope of each of many short-range hotspots, rather than a few powerful stations blotting out the signal for everybody else LOL.

There are many ways to enhance WiFi, and depending on jurisdiction, many of those enhancements ARE illegal. In some countries, the maximum power is specified in ERP (effective radiated power) - which means that enhancement that comes even from big antennas may be illegal. This stands to reason, because of the "blotting out everybody else" thing.

But, there is very lax enforcement. The reason for the lax enforcement is that few people ever complain about the WiFi over-doers. That may be for a couple reasons: (1) - the neighbors have crappy WiFi but don't know that the reason is the crazy neighbor, (2) - not very many people use excessive enhancement, (3)- usually nobody gets killed as a result of WiFi over-doers, and it's too much paperwork to process. If enhancement got to be very popular, then the complaints would rise, and the laws would be more effectively enforced. Same as with anything.

[Ronaldlees]

So, how to extend WiFi range without illegal enhancement?

- Use repeaters/mesh etc.

[Heater]

Ronaldlees,

The reason for the lax enforcement is that few people ever complain about the WiFi over-doers.

No doubt true.

And how many "WiFi over-doers" are there? Most people just use whatever WIFI router/dongle the get out of the box.

On the other hand...

We found that our WIFI was unreliable at one location. Turned out to be down to packets received from a nearby CISCO building. Basically abusing the protocol and license terms. We asked them nicely to stop and they did.

I forget the details now but this is the kind of thing:
https://hackaday.com/2011/10/04/wifi-ja ... n-packets/

CISCO was using that to protect their internal WIFI network. Just over stepping the mark a bit.

[Heater]

Ronaldlees,

The reason for the lax enforcement is that few people ever complain about the WiFi over-doers.

No doubt true.

And how many "WiFi over-doers" are there? Most people just use whatever WIFI router/dongle the get out of the box.

On the other hand...

We found that our WIFI was unreliable at one location. Turned out to be down to packets received from a nearby CISCO building. Basically abusing the protocol and license terms. We asked them nicely to stop and they did. Sometimes it's nice to have the law on your side.

I forget the details now but this is the kind of thing:
https://hackaday.com/2011/10/04/wifi-ja ... n-packets/

CISCO was using that to protect their internal WIFI network. Just over stepping the mark a bit.

[broe23]

So, how to extend WiFi range without illegal enhancement?

- Use repeaters/mesh etc.

Even then, you would have to find spots that you can bounce the signal from my house across the downtown, which would mean hanging the antennas on the side of a building or on top, while dealing with the Cellular units all over our downtown.

There is not a way that someone has figured out how to keep the radio chips cooled enough, along with using that heat for keeping the unit deiced in the winter.

All of the antenna mod's do not make the units illegal, nor would you get in trouble.

[Heater]

broe23,

All of the antenna mod's do not make the units illegal, nor would you get in trouble.

This is not true.

As I have pointed out before there are, in most countries, laws and regulations that limit what you can do on the radio waves.

For example, see the regulations about transmitter power and antenna gain laid down by the FCC: http://afar.net/tutorials/fcc-rules/

If you read, and understand that, you see there are limits to the power you can put into an antenna. Then you find that if you have a high gain, directional antenna, it is required that you reduce the power you put in according to the gain of the antenna.

The bottom line is in that document:

"The responsibility for staying within these power limits falls on the operator"

So then the question is, do you want to break the law or not?

broe23 is correct that often nobody will notice and nothing will happen.

On the other hand, if you are disturbing our systems we will find you and get you shut down, with the full force of the law behind us. As we did with CISCO, see above.

There is not a way that someone has figured out how to keep the radio chips cooled enough, along with using that heat for keeping the unit deiced in the winter.

Also not true.

If it were the cellular network would not have been working in extremes of temperature for decades.

People have been operating equipment in ISM bands in such extremes for decades as well. For example: http://afar.net/wireless/ethernet-bridge/