SIMCom SIM808 GSM GPRS GPS Module Development Board

The SIM808 is controlled via AT commands sent over its UART serial interface. Connect the module's TX and RX pins to your microcontroller's UART, ensuring common ground. Power the module with 3.8V to 4.2V. Use a serial terminal at a baud rate between 1200 and 115200 (auto-detected) and send basic AT commands like 'AT' to check communication. For GPS, send 'AT+CGPS=1' to start it, and NMEA sentences will be output automatically on the serial line.

The module's main operating voltage is typically 3.8V to 4.2V, aligning with a single-cell Li-Ion battery. The onboard charging circuit manages battery charging. Connect your battery's positive terminal to the 'BAT+' pin and negative to 'GND'. When external power (4V-5V) is applied to the '5V' pin, the module will charge the battery. Monitor charging status via specific AT commands. In sleep mode, current draw drops to around 10mA, significantly extending battery life for field deployments.

The board has two u.FL (IPEX) connectors: one for the GSM antenna and one for the GPS antenna. You will need two separate active antennas. For GSM, use a quad-band cellular antenna with a u.FL connector. For GPS, use a passive or active GPS patch antenna with u.FL, ensuring it covers the L1 frequency (1575.42 MHz). Carefully mate the connectors to avoid damaging the fragile u.FL ports. For best GPS performance, position the GPS antenna with a clear view of the sky.

Yes, the SIM808 module can handle concurrent operations. You can have an active GPRS TCP/IP connection for sending sensor data to a cloud server while the GPS is providing location coordinates. The module outputs NMEA GPS data automatically on the serial port. You can parse this data in your microcontroller firmware. Use AT commands like 'AT+CGPS=1' to enable GPS and 'AT+CGATT=1' followed by 'AT+CSTT' to attach to the GPRS network and start a data session.