The SIM900 GSM/GPRS Shield is a wireless communication add-on board that equips your Arduino (Uno, Mega, Leonardo, and compatible boards) with cellular connectivity over 2G GSM networks. At its heart sits the SIMCOM SIM900 module — a widely-deployed, quad-band GSM/GPRS engine operating across 850, 900, 1800, and 1900 MHz bands, covering the GSM frequency allocations used by Indian telecom operators in regions where 2G infrastructure remains active. Whether you need to send SMS alerts, make automated voice calls, push sensor data to a cloud server over GPRS, or build an SMS-controlled home automation system, this shield provides reliable cellular communication without depending on Wi-Fi. The shield stacks neatly onto your Arduino and communicates over a simple UART serial interface with just two pins (TX/RX) and a convenient hardware/software serial selector switch. It features an onboard SIM card holder for standard-size SIMs, an SMA connector for the included GSM antenna, and 3.5 mm jacks for an electret microphone and speaker/headset, so you can build voice-call functionality right out of the box. The onboard voltage regulator handles the module's demanding peak-current requirements of up to 2A during transmission bursts. We strongly recommend a quality 9V to 12V DC adapter rather than USB power alone to avoid brownout resets — a common pitfall for first-time users that we address in our FAQs. AT-command control follows the industry-standard GSM 07.07 and 07.05 command sets, so the shield works effortlessly with a wide range of libraries and community code. You will be sending your first SMS within 30 minutes using the well-documented Arduino SoftwareSerial examples. Status LEDs give you at-a-glance feedback on power, network registration, and active data sessions. Whether you are an engineering student building your final-year IoT project, a hobbyist creating a remote monitoring station, or a professional prototyping an industrial telemetry unit, the SIM900 Shield is a practical, well-supported 2G cellular option for Arduino projects in India.
Audio: 3.5 mm electret mic jack + 3.5 mm speaker/headset jack Weight: 38 g (with antenna) Antenna: SMA female connector + included quad-band antenna Chipset: SIMCOM SIM900 (quad-band) Firmware: Standard open firmware; no carrier lock SIM Card: Standard (full-size) SIM card slot Interface: UART (TX/RX), selectable D0/D1 or D7/D8 SMS Modes: Text mode and PDU mode Data Speed: Downlink: 85.6 kbps, Uplink: 42.8 kbps Dimensions: 68.5 mm x 53.3 mm (standard Arduino shield) GPRS Class: Multi-slot Class 10/8, Mobile Station Class B AT Commands: GSM 07.07, GSM 07.05, SIMCOM enhanced AT LED Indicators: Power, NetLight (network status), Status Frequency Bands: GSM 850 / 900 / 1800 / 1900 MHz Operating Voltage: 5V DC from Arduino (external 9-12V adapter recommended)
Arduino Boards & Compatibles