I have two sim cards. One for sending /receiving messages and calls. And one for Internet surfing. The issues: Switching sim cards is super annoying, no matter which phone I use, the connection is always too bad to do serious Internet surfing (unless I'm in a bigger city, which doesn't usually happen.

Now I'd like to create a battery powered mobile router with badass 2g/3g antennas that takes a simcard to connect to cell towers and provides the internet through a wifi interface.

How bulky would such a thing be?

In terms of price and effort, would it make a significant difference if the device had to be able to allow multiple (2-3) wifi-'clients' to connect at the same time?

What kind of hardware would I need?
A Raspberry Pi? An Arduino? How big would the antenna have to be?

The device can weigh 4 pounds, I wouldn't care. It should simply fit into my pocket, have at least 14 hours battery life, have a stable 3g connection (even when i'm in a train or in a crappy town) and be a stable wifi ap. Oh and it shouldn't break in my pocket (just thinking about those super fragile tiny antenna connectors)...

I'm not looking for dual-sim phones or a new phone in general!

  • A regular android cellphone will do this. Enable "Thetering and mobile hotspot" and your phone will act like a wifi-AP. Sharing his 3G connection. – Paul Nov 2 '15 at 20:36
  • If you really want to do this with arduino, I suggest you break up your project in smaller projects or questions. You should try to figure stuff out yourself also. – Paul Nov 2 '15 at 20:38
  • Erm no. Not even remotely. – Forivin Nov 2 '15 at 20:38
  • If a phone could do this, then I would have simply used my phone. But that's the point, phones don't get a 3g connection where I am. You need a way better antenna. – Forivin Nov 2 '15 at 20:40
  • Best bet is an Arduino Yun coupled with a USB HSDPA dongle. – Majenko Nov 2 '15 at 21:08

-Define the problem-

  • No/bad 3G connection
  • 2 Simcards but not a dual-sim or new phone.
  • Possibility Forivin wants to do this as a hobby project.

--No/Bad 3G connection--

Try boosting your 3G connection of your phone.

--2 Simcards but not a dual-sim or new phone--

  • You can use another android phone and set it to tehtering mode. (It will fit your requirements and is easy. Multiple clients, battery. (Might combine with external attenna)
  • Why not dual-sim? :D

--Hobby project--

It would be very cool to do such a thing by yourself. It would be a shame if I say you shouldn't, but it won't be your best/easiest option, nor the most logical path to take.

  • Break it up into smaller projects. (interfacing with a WIFI adapter alone is already difficult enough. Getting a 3G/sim unit/ battery (with charger) is another.
  • Try finding resources yourself. Are there projects like this? Can you get something working already? Get basic stuff working and expand from there. Doing the whole thing at once will get you nowhere.

---The project: ---

  • Get an WIFI adapter working with arduino. Let it accept connections from phones and check what the phone sends to it when it attempts to connect to a page.

  • Get an GSM (3G simcard+module). Make it connect to the internet (set apn and bearer). Forward the HTTP requests from the wifi connection (through arduino) to the web and fetch the response (which you send by wifi back to the correct client/phone).

  • Make it portable. Find a way to charge the whole lot with a battery pack. Some GSM units support getting fed by a li-ion pack directly. How to regulate the voltage to 5V, maybe even print it on a PCB.

  1. Get a 3G router.

Check it's power usage (rated watt), should be as low as possible. It should have a 3G+simcard connection + wifi tethering. Just choose one that you think fits best, we're not doing any shopping advice. Check if it works for you, if not, return it to the store. (Ask if you can return it (and get money refund) before you buy it.)

  1. Get an external power supply.

Check what rating it has (9V or 12V) and probably check on electronics.stackexchange if they can help with a portable power supply that fits your needs.

Edit: Please just buy something like this, IN A SHOP WHERE YOU CAN GET A REFUND: http://www.ebay.com/itm/Huawei-E5220s-2-Unlocked-3G-GSM-21-Mbps-HSPA-Wireless-Mobile-Hotspot-Router-New-/400789564124?hash=item5d50eb6adc:g:K2gAAOSwPhdVTPtV

DISCLAIMER: You shouldn't buy expensive stuff on E-Bay. At your own risk. Things like this won't arrive or will arrive in a poor state/not work at all.

  • My phone doesn't have an antenna connector and I have never seen a phone that has one. Buying a new phone is not an option for obvious reasons (way too expensive and I have very specific requirements for my phone). Another phone set up to tethering would make things even worse than they are and waste a lot of money. Switching providers is not an option and wouldn't change anything anyway (I tried them all). I'm currently thinking about buying a 3g router and mod it to get powered by a battery or so, but I have not idea which one has low power consumption and external antenna ports etc.. – Forivin Nov 2 '15 at 21:37
  • This is arduino.stackexchange and this would be outside of the scope of arduino? Can you get a 3G router that works for you (if it doesn't work you can return it to the store?)? The problem might be because of bad provider coverage (3G not reaching to those places). If you've got a 3G router working, it's not a question for arduino stack exchange anymore. – Paul Nov 2 '15 at 21:51
  • @Forivin you should get something like this: ebay.com/itm/… Anything self-made will be more expensive and time consuming. If you're not looking to make a fun/edu project off it, it won't be worth your time. Search for "portable 3G wifi" and buy at a store you trust and where you can claim a refund if it won't work. You can try others or just blame your provider that their 3G coverage is too bad. – Paul Nov 2 '15 at 22:03
  • There are no such portable routers in Germany. I'd have to import one and that would be too expensive.. – Forivin Nov 3 '15 at 10:35
  • What is your budget? – Paul Nov 3 '15 at 10:41

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