Hello! I want to send and receive datas by radio frequency between an Arduino module and my smartphone (with an Application created with Appinventor). I have few questions about my project: First, is it possible ??? What radio frequency should i use? (Some are illegals...) Can you give me some advices about the module to use? Thank you
Just use Bluetooth.
Why ? And How?
Victorsin: Why ? And How?
Why? Because it's dead simple, you don't have to worry about it being a legal fz, you have BT in your phone already.... probably more if I thought about it.
How? Buy a Bluetooth shield or module and off you go.
Loads of sites: here's one as an example
Ok, but does bluetooth has a minimum range of 15 meters? I need it
Victorsin: Ok, but does bluetooth has a minimum range of 15 meters? I need it
Well you never mentioned that in your Original Post - we don't read minds here.
You will need to do some experiments.
Your smart phone will also have WiFi but it works on the same general frequency and I don't know if its range would be greater unless you are in an area where the signal can be relayed through a WiFi hub. And using WiFi will make the programming etc more complex.
Of course you could put a GSM module on an Arduino and use the phone system to give you world-wide range. But it would be more expensive.
Bluetooth has a range of up to 100 meters - for certain versions of the protocol. Check the specs before buying specific modules, and of your phone.
It also depends on your environment which you didn't disclose. Walls, trees, water - all can wreak havoc on radio signals.