ESP32 SIM808 GSM/GPRS + GPS Module
The SIM808 is a versatile GSM/GPRS module with integrated GPS functionality, providing quad-band connectivity for voice, SMS, data, and satellite navigation applications. Its compact design and multiple interfaces make it suitable for a wide range of communication and tracking projects.
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About SIM808 GSM/GPRS + GPS Module
The SIM808 is a compact quad-band GSM/GPRS module integrated with GPS technology for satellite navigation. It supports voice, SMS, GPRS data, and GPS, making it suitable for a wide range of applications, including vehicle tracking, wearable devices, and industrial automation. The module offers multiple interfaces such as UART, USB, and GPIO, enhancing its versatility in communication projects.If you are still choosing the SIM Module and would like to know more about different available LTE, 3G, GPRS Modules, check the ESP32 SIM Modules Comparison Table.
SIM808 Sensor Technical Specifications
Below you can see the SIM808 GSM/GPRS + GPS Module Technical Specifications. The sensor is compatible with the ESP32, operating within a voltage range suitable for microcontrollers. For precise details about its features, specifications, and usage, refer to the sensor’s datasheet.
- Protocol: UART
- Frequency Bands: Quad-band 850/900/1800/1900MHz
- Supply Voltage: 3.4V to 4.4V
- Power Consumption (Sleep Mode): 1.0mA
- Dimensions: 24mm x 24mm x 2.6mm
- Operating Temperature: -40°C to +85°C
- GPRS Connectivity: GPRS multi-slot class 12
- GPS Sensitivity: -165 dBm
- Interfaces: UART, USB, SIM, GPIO, GPS
SIM808 Sensor Pinout
Below you can see the pinout for the SIM808 GSM/GPRS + GPS Module. The VCC
pin is used to supply power to the sensor, and it typically requires 3.3V or 5V (refer to the datasheet for specific voltage requirements). The GND
pin is the ground connection and must be connected to the ground of your ESP32!
The SIM808 pinout includes:
- VBAT: Power supply input (3.4V to 4.4V).
- GND: Ground connection.
- TXD: UART Transmit Data (connects to microcontroller RX).
- RXD: UART Receive Data (connects to microcontroller TX).
- PWRKEY: Power on/off control (active low).
- NETLIGHT: Network status indication.
- STATUS: Module operating status indication.
- GPS_VCC: GPS power supply.
- GPS_TX: GPS UART Transmit Data.
- GPS_RX: GPS UART Receive Data.
- SIM_VDD: SIM card power supply.
- SIM_DATA: SIM card data I/O.
- SIM_CLK: SIM card clock.
- SIM_RST: SIM card reset.
SIM808 Wiring with ESP32
Below you can see the wiring for the SIM808 GSM/GPRS + GPS Module with the ESP32. Connect the VCC pin of the sensor to the 3.3V pin on the ESP32 or external power supply for power and the GND pin of the sensor to the GND pin of the ESP32. Depending on the communication protocol of the sensor (e.g., I2C, SPI, UART, or analog), connect the appropriate data and clock or signal pins to compatible GPIO pins on the ESP32, as shown below in the wiring diagram.
- Connect
VBAT
to a stable power supply within the range of 3.4V to 4.4V. - Connect
GND
to the ground of the microcontroller. - Connect
TXD
to the RX pin of the microcontroller andRXD
to the TX pin. - Connect
PWRKEY
to a GPIO pin on the microcontroller; to power on the module, pull this pin low for at least 1 second. - Optionally, connect
NETLIGHT
andSTATUS
pins to LEDs for network and status indications. - For GPS functionality, connect
GPS_VCC
to a 3.3V power supply, andGPS_TX
andGPS_RX
to the microcontroller's UART pins if separate from the GSM UART. - For SIM card connections, connect
SIM_VDD
,SIM_DATA
,SIM_CLK
, andSIM_RST
to the corresponding pins on the SIM card holder.
Code Examples
Below you can find code examples of SIM808 GSM/GPRS + GPS Module with ESP32 in several frameworks:
If you encounter issues while using the SIM808 GSM/GPRS + GPS Module, check the Common Issues Troubleshooting Guide.
ESP32 SIM808 Arduino IDE Code Example
Fill in your main
Arduino IDE sketch file with the following code to use the SIM808 GSM/GPRS + GPS Module:
#include <SoftwareSerial.h>
SoftwareSerial sim808(10, 11); // RX, TX
void setup() {
Serial.begin(9600);
sim808.begin(9600);
// Power on the module
pinMode(9, OUTPUT);
digitalWrite(9, LOW);
delay(1000); // PWRKEY needs to be low for at least 1 second
digitalWrite(9, HIGH);
delay(5000); // Wait for the module to initialize
// Test AT communication
sim808.println("AT");
delay(1000);
while (sim808.available()) {
Serial.write(sim808.read());
}
}
void loop() {
// Send an SMS
sim808.println("AT+CMGF=1"); // Set SMS to text mode
delay(1000);
sim808.println("AT+CMGS=\"+1234567890\""); // Replace with recipient's number
delay(1000);
sim808.print("Hello from SIM808");
delay(1000);
sim808.write(26); // CTRL+Z to send SMS
delay(5000);
}
This Arduino sketch interfaces with the SIM808 module using the SoftwareSerial library. The module is powered on by toggling the PWRKEY pin. An AT command is sent to verify communication. In the loop, the sketch demonstrates how to send an SMS by setting the module to SMS text mode, specifying the recipient's number, and sending the message. The GPS functionality is initialized, and the GPS location is printed to the serial monitor if available.
Connect your ESP32 to your computer via a USB cable, Ensure the correct Board and Port are selected under Tools, Click the "Upload" button in the Arduino IDE to compile and upload the code to your ESP32.
ESP32 SIM808 ESP-IDF Code ExampleExample in Espressif IoT Framework (ESP-IDF)
If you're using ESP-IDF to work with the SIM808 GSM/GPRS + GPS Module, here's how you can set it up and read data from the sensor. Fill in this code in the main
ESP-IDF file:
#include <stdio.h>
#include "driver/uart.h"
#include "driver/gpio.h"
#include "freertos/task.h"
#define TX_PIN 17
#define RX_PIN 16
#define PWRKEY_PIN 4
#define UART_PORT UART_NUM_1
#define GPS_UART_PORT UART_NUM_2
void init_uart() {
uart_config_t uart_config = {
.baud_rate = 9600,
.data_bits = UART_DATA_8_BITS,
.parity = UART_PARITY_DISABLE,
.stop_bits = UART_STOP_BITS_1,
.flow_ctrl = UART_HW_FLOWCTRL_DISABLE
};
uart_param_config(UART_PORT, &uart_config);
uart_set_pin(UART_PORT, TX_PIN, RX_PIN, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
uart_driver_install(UART_PORT, 1024, 0, 0, NULL, 0);
}
void power_on_sim808() {
gpio_set_direction(PWRKEY_PIN, GPIO_MODE_OUTPUT);
gpio_set_level(PWRKEY_PIN, 0);
vTaskDelay(1000 / portTICK_PERIOD_MS); // Hold PWRKEY low for 1 second
gpio_set_level(PWRKEY_PIN, 1);
vTaskDelay(5000 / portTICK_PERIOD_MS); // Wait for the module to initialize
}
void app_main(void) {
init_uart();
power_on_sim808();
char *test_cmd = "AT\r\n";
uart_write_bytes(UART_PORT, test_cmd, strlen(test_cmd));
while (true) {
char data[128];
int len = uart_read_bytes(UART_PORT, data, sizeof(data), 100 / portTICK_PERIOD_MS);
if (len > 0) {
data[len] = '\0';
printf("Response: %s\n", data);
}
vTaskDelay(1000 / portTICK_PERIOD_MS);
}
}
This ESP-IDF example initializes UART communication with the SIM808 module and powers it on using the PWRKEY pin (GPIO4). The UART interface is configured with GPIO17 as TX and GPIO16 as RX. An AT command is sent to test communication, and responses from the module are printed to the console. Additional UART configurations can be added for GPS functionality.
Update the I2C pins (I2C_MASTER_SDA_IO
and I2C_MASTER_SCL_IO
) to match your ESP32 hardware setup, Use idf.py build to compile the project, Use idf.py flash to upload the code to your ESP32.
ESP32 SIM808 ESPHome Code Example
Fill in this configuration in your ESPHome YAML configuration file (example.yml
) to integrate the SIM808 GSM/GPRS + GPS Module
uart:
tx_pin: GPIO17
rx_pin: GPIO16
baud_rate: 9600
switch:
- platform: gpio
name: "SIM808 Power"
pin:
number: GPIO4
inverted: true
switch:
- platform: template
name: "Send AT Command"
turn_on_action:
- uart.write: "AT\r\n"
sensor:
- platform: custom
lambda: |-
return {nullptr};
sensors:
- name: "SIM808 Response"
The ESPHome configuration sets up UART communication with the SIM808 using GPIO17 (TX) and GPIO16 (RX) at 9600 baud. A GPIO-based switch is used to control the PWRKEY pin (GPIO4) for powering the module on or off. A template switch allows sending the AT command, and a custom sensor can be implemented to process responses from the module. GPS functionality can also be integrated through additional configuration.
Upload this code to your ESP32 using the ESPHome dashboard or the esphome run
command.
ESP32 SIM808 PlatformIO Code Example
For PlatformIO, make sure to configure the platformio.ini
file with the appropriate environment and libraries, and then proceed with the code.
Configure platformio.ini
First, your platformio.ini
should look like below. You might need to include some libraries as shown. Make sure to change the board to your ESP32:
[env:sim808]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
ESP32 SIM808 PlatformIO Example Code
Write this code in your PlatformIO project under the src/main.cpp
file to use the SIM808 GSM/GPRS + GPS Module:
#include <HardwareSerial.h>
#include <Arduino.h>
HardwareSerial sim808(1);
#define PWRKEY 4
void power_on_sim808() {
pinMode(PWRKEY, OUTPUT);
digitalWrite(PWRKEY, LOW);
delay(1000); // Hold PWRKEY low for 1 second
digitalWrite(PWRKEY, HIGH);
delay(5000); // Wait for initialization
}
void setup() {
Serial.begin(115200);
sim808.begin(9600, SERIAL_8N1, 16, 17); // RX, TX
power_on_sim808();
// Test AT command
sim808.println("AT");
delay(1000);
while (sim808.available()) {
Serial.write(sim808.read());
}
}
void loop() {
sim808.println("AT+CMGF=1"); // Set SMS to text mode
delay(1000);
sim808.println("AT+CMGS=\"+1234567890\""); // Replace with recipient's number
delay(1000);
sim808.print("Hello from PlatformIO");
delay(1000);
sim808.write(26); // CTRL+Z to send SMS
delay(5000);
}
This PlatformIO code interfaces with the SIM808 module using HardwareSerial on an ESP32. The `power_on_sim808` function toggles the PWRKEY pin (GPIO4) to activate the module. The AT command is sent to test communication, and SMS functionality is implemented in the loop. GPIO16 (RX) and GPIO17 (TX) are configured as serial pins.
Upload the code to your ESP32 using the PlatformIO "Upload" button in your IDE or the pio run --target upload
command.
ESP32 SIM808 MicroPython Code Example
Fill in this script in your MicroPython main.py file (main.py
) to integrate the SIM808 GSM/GPRS + GPS Module with your ESP32.
from machine import UART, Pin
import time
# Initialize UART
uart = UART(2, baudrate=9600, tx=17, rx=16)
pwrkey = Pin(4, Pin.OUT)
def power_on_sim808():
pwrkey.value(0)
time.sleep(1) # Hold PWRKEY low for 1 second
pwrkey.value(1)
time.sleep(5) # Wait for module to initialize
def send_at(command):
uart.write(command + '\r\n')
time.sleep(1)
while uart.any():
print(uart.read().decode('utf-8'), end='')
# Power on the module
power_on_sim808()
# Test communication
send_at('AT')
# Send SMS
send_at('AT+CMGF=1') # Set SMS to text mode
send_at('AT+CMGS="+1234567890"') # Replace with recipient's number
uart.write("Hello from MicroPython" + chr(26))
This MicroPython code communicates with the SIM808 module over UART. The `power_on_sim808` function activates the module using the PWRKEY pin (GPIO4). The `send_at` function sends AT commands and prints the responses. The script initializes the module, tests communication, and sends an SMS with a specified message. Additional logic can be added to read GPS data through UART.
Upload this code to your ESP32 using a MicroPython-compatible IDE, such as Thonny, uPyCraft, or tools like ampy
.
SIM808 GSM/GPRS + GPS Module Troubleshooting
This guide outlines a systematic approach to troubleshoot and resolve common problems with the . Start by confirming that the hardware connections are correct, as wiring mistakes are the most frequent cause of issues. If you are sure the connections are correct, follow the below steps to debug common issues.
Module Fails to Power On
Issue: The SIM808 module does not power up or respond to commands.
Possible causes include insufficient power supply, incorrect wiring, or faulty hardware.
Solution: Ensure the module is connected to a stable power source within the recommended voltage range of 3.4V to 4.4V. Verify that all connections are secure and correctly configured. If the problem persists, consider testing the module with a different power source or replacing it.
SIM Card Not Recognized
Issue: The module fails to detect or register the SIM card.
Possible causes include improper SIM card insertion, unsupported SIM card type, or SIM card lock.
Solution: Ensure the SIM card is properly inserted into the module's SIM card slot and is compatible with the GSM network. Verify that the SIM card is active and unlocked. If necessary, test the SIM card in another device to confirm its functionality.
Poor Network Signal or Connectivity Issues
Issue: The module experiences weak signal strength or fails to maintain a stable network connection.
Possible causes include improper antenna connection, environmental interference, or network coverage limitations.
Solution: Ensure the GSM antenna is securely connected to the module and positioned for optimal signal reception. Avoid placing the module near sources of electromagnetic interference. Check the network coverage in your area to ensure adequate signal strength.
AT Commands Not Responding
Issue: The module does not respond to AT commands sent from the microcontroller or computer.
Possible causes include incorrect baud rate settings, faulty serial connections, or improper command syntax.
Solution: Verify that the baud rate of the module matches that of the microcontroller or computer; the default baud rate is 9600 bps. Check that the TX and RX lines are correctly connected and that there are no loose connections. Ensure that AT commands are correctly formatted and terminated with a carriage return.
GPS Functionality Not Working
Issue: The SIM808 module fails to acquire GPS signals or provide location data.
Possible causes include improper antenna connection, obstructed view of the sky, or GPS functionality not enabled.
Solution: Ensure the GPS antenna is properly connected and has a clear view of the sky to receive satellite signals. Verify that the GPS functionality is enabled by sending the appropriate AT commands to power on the GPS engine.
Conclusion
We went through technical specifications of SIM808 GSM/GPRS + GPS Module, its pinout, connection with ESP32 and SIM808 GSM/GPRS + GPS Module code examples with Arduino IDE, ESP-IDF, ESPHome and PlatformIO.