user28745: I am trying to make a WiFi internet network from 3G using Arduino as access control. I need the Arduino to act as server and control users, consumption, and connection speed. (When users connect to the WiFi, they have to enter a passcode in a webpage to use internet for a limited time,  or limited data.)
So is this possible? I still did not try anything because I can not afford to buy many objects and fail to make it work.
I am thinking of using a 3G shield and a WiFi shield, or a router connected to 3G dongle connected to an Arduino via ethernet, or a 3G shield Arduino to ethernet shield to WiFi router.
I don't know if any of these can work, so I really appreciate any guidance.

user4143: Not a chance, I am afraid (you were right not to buy things yet). Things like the 3G shield and WiFi shield don't work in the way that is needed for a WiFi hotspot like that. You're better off with a Raspberry Pi and a 3G USB dongle and run hostapd along with the other software needed for your project - things like apache, etc.
You may be able to do it with the Linux portion (OpenWRT) of an Arduino Yun with a USB 3G dongle attached, but it would be sluggish. Best to stick to something with enough processing to do what you want, which means a Raspberry Pi or similar.

28745: <p>I am trying to make a WiFi internet network from 3G using Arduino as access control. I need the Arduino to act as server and control users, consumption, and connection speed. (When users connect to the WiFi, they have to enter a passcode in a webpage to use internet for a limited time,  or limited data.)</p>

<p>So is this possible? I still did not try anything because I can not afford to buy many objects and fail to make it work.</p>

<p>I am thinking of using a 3G shield and a WiFi shield, or a router connected to 3G dongle connected to an Arduino via ethernet, or a 3G shield Arduino to ethernet shield to WiFi router.</p>

<p>I don't know if any of these can work, so I really appreciate any guidance.</p>
 4143: <p>Not a chance, I am afraid (you were right not to buy things yet). Things like the 3G shield and WiFi shield don't work in the way that is needed for a WiFi hotspot like that. You're better off with a Raspberry Pi and a 3G USB dongle and run <code>hostapd</code> along with the other software needed for your project - things like apache, etc.</p>

<p>You may be able to do it with the Linux portion (OpenWRT) of an Arduino Yun with a USB 3G dongle attached, but it would be sluggish. Best to stick to something with enough processing to do what you want, which means a Raspberry Pi or similar.</p>
