How to Use Adafruit FONA 800 Shield: Examples, Pinouts, and Specs

The Adafruit FONA 800 Shield is an invaluable addition to the Arduino ecosystem, providing GSM/GPRS functionality to your projects. This shield allows for cellular communication, enabling devices to make calls, send texts, and connect to the internet over a mobile network. It's perfect for remote monitoring, asset tracking, and any application where wireless communication is required.

• Remote data logging and telemetry
• SMS-based remote control
• Asset tracking and geolocation
• Emergency communication systems
• IoT devices requiring cellular connectivity

• Network Support: Quad-band 850/900/1800/1900MHz - works on GSM networks worldwide.
• Voltage Requirements: 3.4-4.4VDC logic level (5V safe).
• Current Consumption: 250mA average during transmission.
• Onboard Regulator: 3.3V 800mA regulator.
• Antenna Connector: SMA connector for external antenna.
• SIM Card Slot: Standard 2FF SIM slot.

1. Powering the Shield: Connect the Vio pin to a 3.3V or 5V power supply from your microcontroller.
2. Ground Connection: Connect the GND pin to the ground of your microcontroller.
3. UART Communication: Connect the RX and TX pins to the corresponding TX and RX pins on your microcontroller.
4. Antenna: Attach an appropriate GSM antenna to the SMA connector.
5. SIM Card: Insert an activated GSM SIM card into the SIM card slot.

• Ensure that the power supply can handle the peak current requirements during transmission.
• Use a level shifter if your microcontroller operates at a logic level different from 3.3V or 5V.
• Place the antenna in a position where it is not obstructed by metal objects to ensure good signal reception.
• Always power down the shield before inserting or removing the SIM card to prevent damage.

#include <SoftwareSerial.h>

SoftwareSerial fonaSerial(2, 3); // RX, TX
// Use pin 2 to communicate with the FONA

void setup() {
  fonaSerial.begin(4800); // Set the baud rate for the FONA
  Serial.begin(115200);   // Set the baud rate for Serial monitor
  Serial.println(F("FONA basic test"));
  Serial.println(F("Initializing....(May take a few seconds)"));

  // Make sure the FONA is turned on. It should be an active low signal.
  pinMode(4, OUTPUT);
  digitalWrite(4, LOW);
  delay(1000);
  digitalWrite(4, HIGH);
}

void loop() {
  // Check for any incoming calls
  if (fonaSerial.available()) {
    Serial.write(fonaSerial.read());
  }

  // Send any characters from the Serial Monitor to the FONA
  if (Serial.available()) {
    fonaSerial.write(Serial.read());
  }
}

• No Network Connection: Ensure the antenna is properly connected and the SIM card is activated and has network coverage.
• Power Issues: If the module does not power on, check the power supply and connections.
• Serial Communication Errors: Verify that the baud rate of the FONA and the microcontroller's serial port match.

• Power Cycling: If the module is unresponsive, try power cycling by turning it off and on again.
• Antenna Placement: Move the antenna to a different location to avoid interference and improve signal strength.
• SIM Card Activation: Confirm that the SIM card is activated with the carrier and has the correct APN settings for data transmission.

• Q: Can I use the FONA 800 Shield with a 3.3V microcontroller?

  • A: Yes, the shield is 3.3V logic level compatible, but ensure that the power supply can provide sufficient current.

• Q: How do I know if the FONA 800 Shield is connected to the network?

  • A: The Netlight pin will blink at different rates to indicate the network status.

• Q: What should I do if I can't send or receive SMS?

  • A: Check the SIM card for proper insertion, activation, and SMS plan availability. Also, ensure the antenna has a strong signal.

This documentation provides a comprehensive guide to using the Adafruit FONA 800 Shield with your Arduino projects. For further assistance, consult the Adafruit forums and support channels.