SIM900 GSM GPRS Arduino shield is compatible with any Arduino and its clones (like Uno and Mega). It can be used to dial and receive phone calls and SMS plus connecting to the internet with the GPRS network and can be controlled with Serial connection using AT commands. It supports quad-band GSM 850 MHz, GSM 900 MHz, DCS 1800 MHz, or PCS 1900 MHz networks. a power jack is available with a toggle switch to use an external power supply. SIM900 shield can be powered with any 5V power supply that can provide 2A current or 9V, 1A or 12V, 1A supply. a microphone and a speaker jack are available onboard for phone calls. At the backside of the shield, there is a sim card jack and a holder for a 3V CR1220 battery for the RTC (real-time clock). After insertion of sim and battery, the shield can be mounted on top of the Arduino board.

Specifications:

• Compatible with Arduino and its clones
• Quad Band 850 / 900/ 1800 / 1900 MHz GSM network
• Can send and receive SMS, MMS, GPRS, and audio using GSM network.
• Supports UART interface
• AT commands
• Embedded TCP/UDP stack facility for uploading data to a web server
• RTC support
• Speaker and Headphone jacks
• Equipped with 12 GPIOs, 2 PWMs, and an ADC
• Low power consumption – 1.5mA(sleep mode)
• Industrial Temperature Range – -40°C to +85 °C
  
  

Application:

• M2M (Machine 2 Machine) Applications.
• Remote control of appliances.
• Remote Weather station or a Wireless Sensor Network.
• Vehicle Tracking System with a GPS module.

Pinout of SIM900 GSM GPRS Board

Connecting the GSM SIM900 GPRS IoT Shield to Arduino:

Arduino Code for GSM SIM900 GPRS IoT Shield to send an SMS:

#include "SoftwareSerial.h"
//Create software serial object to communicate with SIM900
SoftwareSerial mySerial(7, 8); //SIM900 Tx & Rx is connected to Arduino #7 & #8
void setup()
{
 //Begin serial communication with Arduino and Arduino IDE (Serial Monitor)
 Serial.begin(9600);
 //Begin serial communication with Arduino and SIM900
 mySerial.begin(9600);
 Serial.println("Initializing...");
 delay(1000);
 mySerial.println("AT"); //Handshaking with SIM900
 updateSerial();
 mySerial.println("AT+CMGF=1"); // Configuring TEXT mode
 updateSerial();
 mySerial.println("AT+CMGS=\"+ZZxxxxxxxxxx\"");//change ZZ with country code and xxxxxxxxxxx with phone number to sms
 updateSerial();
 mySerial.print("Last Minute Engineers | lastminuteengineers.com"); //text content
 updateSerial();
 mySerial.write(26);
}
void loop()
{
}
void updateSerial()
{
 delay(500);
 while (Serial.available())
 {
 mySerial.write(Serial.read());//Forward what Serial received to Software Serial Port
 }
 while(mySerial.available())
 {
 Serial.write(mySerial.read());//Forward what Software Serial received to Serial Port
 }
}