How to Use Sim800l: Examples, Pinouts, and Specs

The SIM800L is a compact and versatile wireless module that offers GSM/GPRS functionality, enabling devices to communicate via mobile network services. It is widely used in a variety of applications such as remote data logging, SMS-based remote control, security systems, GPS tracking, and IoT (Internet of Things) devices. Its small form factor and low power consumption make it ideal for mobile applications and embedded systems.

• Quad-band 850/900/1800/1900MHz
• GPRS multi-slot class 12/10
• GPRS mobile station class B
• Compliance with GSM phase 2/2+
• Class 4 (2 W @ 850/900 MHz)
• Class 1 (1 W @ 1800/1900MHz)

• Voltage range: 3.4V - 4.4V (optimal at 4.0V)
• Current: 1A or more during transmission bursts

• Control via AT commands (3GPP TS 27.007, 27.005)
• Serial port baud rate: 1200 to 115200 bps (default 9600)

• Dimensions: 15.8 x 17.8 x 2.4 mm
• Weight: 1.35g

1. Power Supply: Connect a stable power source capable of delivering up to 2A during transmission bursts to the VCC and GND pins. It is recommended to use a 4V power supply.
2. Serial Communication: Connect the RXD and TXD pins to the corresponding TX and RX pins of your microcontroller (e.g., Arduino UNO). Remember to cross-connect RX to TX and TX to RX.
3. Antenna: Attach an appropriate GSM antenna to the antenna pad for signal reception.

• Ensure that the power supply is sufficient and stable.
• Use a level shifter if connecting to a 5V logic microcontroller.
• Place the module away from noise sources and metal objects.
• Always attach an antenna before powering up the module to avoid damage.

#include <SoftwareSerial.h>

SoftwareSerial SIM800L(10, 11); // RX | TX

void setup() {
  // Set baud rate for communication.
  SIM800L.begin(9600);
  Serial.begin(9600);
  
  // Check communication with SIM800L module.
  Serial.println("Initializing...");
  delay(1000);
  SIM800L.println("AT");
}

void loop() {
  // Forward every message from SIM800L to Serial Monitor.
  if (SIM800L.available()) {
    Serial.write(SIM800L.read());
  }
  // Forward every message from Serial Monitor to SIM800L.
  if (Serial.available()) {
    SIM800L.write(Serial.read());
  }
}

• Power Issues: The module does not power up or frequently restarts.
  • Solution: Check the power supply for adequate current output. Use a supply that can deliver up to 2A.
• Signal Issues: Poor signal strength or no network registration.
  • Solution: Ensure the antenna is properly connected and positioned. Check for any obstructions or interference.

Q: Can I use the SIM800L with a 5V microcontroller like Arduino UNO? A: Yes, but you will need a level shifter for the RX and TX lines to protect the SIM800L from 5V signals.

Q: How can I send an SMS using SIM800L? A: You can send an SMS by issuing AT commands through the serial interface. For example, use AT+CMGF=1 to set the text mode and AT+CMGS="number" to send an SMS.

Q: What is the default baud rate of the SIM800L? A: The default baud rate is 9600 bps.

Q: How do I know if the SIM800L is connected to the network? A: You can send the AT+CREG? command to check the network registration status.

Q: Why does my SIM800L get hot during operation? A: It is normal for the SIM800L to get warm due to power consumption during transmission. Ensure adequate ventilation and do not cover the module.

This documentation provides a comprehensive guide to integrating and using the SIM800L module in your projects. For further assistance, consult the manufacturer's datasheet and technical resources.