The SIM900A GSM/GPRS Board is a robust and highly popular communication module designed for the Asian and African markets. At Electrapac, we recommend this board for its stability and "Extra Heavy Duty" reliability in industrial and remote monitoring applications.

Product Overview

The SIM900A module allows your Arduino or other microcontrollers to communicate over the cellular network. It can send and receive SMS, make and receive voice calls, and connect to the internet via GPRS—essentially giving your project the communication power of a mobile phone.

Key Features for Electrapac Customers

• TTL Level Matching: This board is specially designed for Arduino compatibility. It features level-shifting circuitry, meaning you can connect it directly to 5V Arduino pins without needing external resistors or converters.

• Dual Antenna Support: Most kits from www.electrapac.com include a high-gain SMA Antenna for maximum signal strength, but the board also features an IPX/U.FL connector for compact, internal antennas.

• Power Protection: Includes a large 1000uF capacitor to handle the high current spikes (up to 2A) required during network registration and transmission.

• Embedded TCP/IP Stack: Allows you to easily connect to web servers and cloud platforms using simple AT commands.

• Full IO Lead-out: Every functional pin of the SIM900A is broken out to standard headers, making it easy to use the PWM, ADC, and Audio features.

Critical Setup Tips

1. Power Supply is Key: Do NOT power this module directly from the Arduino’s 5V pin. While it may turn on, it will likely reset or fail to register on the network when it tries to transmit. Use a dedicated 5V 2A external power adapter.

2. LED Status: * Blinking Fast: Searching for network.

   • Blinking Slow (every 3 seconds): Successfully registered on the network.

3. The "Wait" Rule: After powering on, wait about 15–30 seconds for the module to establish a connection before sending your first AT command.

Applications

• Remote Security: SMS-based home alarm systems.

• Agriculture: Remote pump control and soil moisture reporting.

• IoT Data Logging: Sending sensor data to a remote SQL database via GPRS.

• Vehicle Tracking: Combined with a GPS module (like the NEO-6M) for location reporting.