Calling android device in WIFI local network

I need to have an application (Android or Linux) that create a local network to send data packets to other android devices (40 max.). This application need to start the run condition from a key received from an external USB device; otherwise the application will show a dialog box error with the “No sensor detected” message. After the start, the application wait the second key sent from the external device. When the app receive the second key, it will send a data packet (5 bytes including key) in the WIFI local network, after the T0 time, to the first group of clients in the network (It is possible to consider client’s group as subnet with the same IP address in the network). After the T0+T1 time, the application will send another data packet in the WIFI local network to the second group of clients. Then the app will send other data packet after T0+ (2*T1) time, other data after T0+ (3*T1), etc. The calling transmission will terminate when the app call the last subnet in the network. That is the main goal of the application. It is necessary to put as input some parameters: SSID: name of the WIFI local network PASSWORD_NET: password to enter in the net PASSWORD_OPERATOR: password to access in the configuration dialog box (It is necessary to modify T0, T1, N_client, N_sub) T0: time expressed in milliseconds T1: time expressed in milliseconds N_client: Numbers of clients in each subnet (All subnet have the same number of clients) N_sub: Number of subnet present Notes: IP address of access point (where the app run) is the first IP address of the WIFI local network and it is not changeable, for example [login to view URL] I need to have an application (Android or Linux) that create a local network to send data packets to other android devices.