SIM900A GPRS Modem TC35

Description

What it is

The SIM900A GPRS TC35 module is a component for Arduino that allows integrating cellular communication into projects. This module offers GSM/GPRS functionality, enabling SMS sending and internet connectivity through a cellular network.

Features

• Supports GPRS protocol for mobile data connections
• Allows SMS sending
• Compatible with Arduino and other microcontrollers

What it is for

SIM900A modules are useful for creating telemetry projects, remote monitoring systems, and alarm systems. For example, you can connect a motion detector to the module and send SMS notifications when the system is triggered.

Tutorial: How to use SIM900A GPRS TC35 module

The SIM900A GPRS TC35 module is a crucial component for creating wireless communication projects. This GSM/GPRS module allows you to send SMS and connect to the internet via a cellular network, making it perfect for both beginners and experienced makers.

What you need

• Arduino Uno or compatible
• Active SIM card with GPRS data
• Connection to PC via USB

Steps

1. 1. Connect the TX and RX pins of the module to those of the Arduino shield.
2. 2. Connect VCC and GND between the module and the Arduino power supply.
3. 3. Configure serial communication in Arduino IDE (baud rate 9600).
4. 4. Insert an active SIM card into the module cavity.
5. 5. Download the necessary drivers for USB to TTL communication.
6. 6. Load the example sketch provided with the module onto the Arduino.
7. 7. Open Serial Monitor in Arduino IDE and send a test SMS command.
8. 8. Verify that the MSIM responds correctly to received commands.

Example code

void setup() {
  Serial.begin(9600);
}

void loop() {
  if (Serial.available()) {
    String command = Serial.readStringUntil('r');
    // Esegui il comando e invia la risposta
  }
}

Mini project

Create an alarm system that sends SMS when triggered. Connect a motion detector to the SIM900A module and write a sketch to handle notifications.

Common mistakes

• The module does not respond: check the serial configuration.
• Incorrect connection with the PC: check the USB to TTL drivers.
• Network issues: ensure the SIM is active and has GPRS data.
• SMS commands do not work: re-read the module documentation.

Recommended accessories

• Arduino Uno
• SIM cards with GPRS data
• USB TTL cable
• 3.7V LiPo battery

Frequently asked questions

What baud rates should I use?
Check the module’s datasheet for the correct value.

How can I check if the SIM is recognized?
Send an AT+CIMI command and verify that the SIM’s IMEI is returned.