Arduino Sim900

A SIM900-based cellular module that lets a microcontroller send SMS, place voice calls and open GPRS data connections over a standard SIM card. Controlled with plain AT commands over a serial port, which makes it straightforward to drive from an Uno or Mega. Before you buy, confirm that your operator still runs a 2G network in your area — many carriers worldwide have shut 2G down, and this module cannot fall back to 3G or 4G. Also plan your power supply properly: transmission bursts draw up to 2A, far more than an Arduino's regulator can deliver. Sends and receives SMS from any microcontroller; Quad-band operation works across most GSM regions; Simple AT command control over serial; Supports GPRS data as well as voice