GSM/GPS Localizer with SIM908 module

The device is based on a GSM/GPRS module with included GPS. Its main function is to detect and communicate its own geographical position using, on the choice, the cellular phone reference system or the GPS. Its small dimensions are due to the use, for the first time, of a GSM/GPRS module integrating the GPS receiver. That is the SIM908 a recent pr
GSM/GPS Localizer with SIM908 module - schematic

oduct by SIMCOM. The circuit of the localizer is build around two boards, one with the SIM908 on board and the second one including the microcontroller and the battery charger for the lithium battery. To get the GPS working will be necessary to complete the localizer circuit with an appropriate antenna. The circuit includes the mother board, mounting the microcontroller and its circuitry, and the daughter board mounting the communication module, the block named GSM in the schema. The reference numbers associated to the contacts on the GSM block correspond to the pins of the connector linking the daughterboard to the motherboard. The program running in the microcontroller U1, one PIC18LF6722, waits for an incoming event or for the button P1 being pushed. While the button is pressed the line RB1, provided with internal pull-up resistor, switches from logical level 1 to the logical level 0, In case of incoming of an SMS message, the program reacts depending on the content of the message that could be a configuration message or a geographical position request. Let focus on the process aimed to retrieve the geographical position, that is quite the same in both cases of manual request and P1 pushing (alarm or S. O. S. ). After the request has been detected, the program in the PIC microcontroller sends commands to the cellular module in order to have it connected to Internet in GPRS mode. Then connects to the Google Maps server...

Leave Comment

characters left:

New Circuits