WiFi Direct is a rapid data sending technology that works without AP(Access Point) internet connection due to its Wi-Fi connection. Since it is an advanced technology that combined pros of Wi-Fi and Bluetooth, it uses the Wi-Fi communication which is faster than a Bluetooth connection.
General Wi-Fi need at least one AP wired cable because it uses cable with wireless network. However, WiFi Direct does not need a separate AP since it can communicate like a Bluetooth at least with 2 devices.
WizFi250 also provide WiFi Direct function.
Download the related code with following link.
http://wizwiki.net/wiki/doku.php?id=products:wizfi250:wizfi250pg:wifi-direct
AT commands to use WiFi Direct
Let’s talk about commands to used WizFi250 as a WiFi Direct mode.
WiFi Command
- AT+WP2P_START
- AT+WP2P_STOP
- AT+WP2P_PEERLIST
- AT+WP2P_INVITE
Network Command
- AT+SCON
- AT+SSEND
4 commands are used to use WiFi Direct function and 2 commands are need for data communication after the connection.
Click the link to find out all of WizFi250 AT Command.
http://wizwiki.net/wiki/doku.php?id=products:wizfi250:wizfi250pg:at_command_set&#at_command_set
Using WiFi Direct
Let’s implement a real WiFi Direct with commands. The Block Diagram is shown below.
WiFi Direct Negotiation
Connected with Device ID:G2 after activating WizFi250’s Direct WiFi mode.
Priority exists of being Owner on the process of WiFi Direct for each device. Smart phones become the Owner in the process of connecting a smart phone and WizFi250 since smart phones have higher priority than WizFi250.
Connect devices then create a TCP Server socket
Created TCP Server socket on WizFi250 as 4000 port after the connection.
After attempting Device Id: Kaizen G2to have a connection with Device ID: G2 which is the Group Owner, I created a 4001 port of TCP server socket on WizFi250-P2P.
Possible to check devices connected with Device ID: G2; the Group Owner.
Data communication
I am going to try data communication while 3 devices are tied up as a group.
The ttttt is the data sent to WizFi250 from G2 and aaaaa is the data sent to WizFi250 from Kaizen G2.
Data sent to devices from WizFi250can be checked with a socket terminal tool of Smartphones.
출처 : Danel’s Blog
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