How to Use Wifi module ESP8266-01: Examples, Pinouts, and Specs

The ESP8266-01 is a highly integrated Wi-Fi module that offers a complete and self-contained networking solution, allowing it to either host an application or offload all Wi-Fi networking functions from another application processor. Manufactured by AZDelivery, the ESP8266-01 is based on the ESP8266 chip and is widely used in Internet of Things (IoT) applications due to its compact size, low cost, and robust feature set.

• Smart home devices
• Wi-Fi enabled sensors
• Wireless data logging
• Remote control systems
• IoT prototypes and projects

• Operating Voltage: 3.0V to 3.6V
• Recommended Operating Voltage: 3.3V
• Operating Current: Average ~80mA
• Wireless Standard: 802.11 b/g/n
• Frequency Range: 2.4 GHz - 2.5 GHz (2400M - 2483.5M)
• Serial/UART baud rate: 115200 bps (default, can be changed)
• Flash Memory: 1MB

1. Connect VCC to a stable 3.3V power supply.
2. Connect GND to the ground of the power supply.
3. Connect CH_PD to VCC to enable the chip.
4. Connect RST to VCC through a pull-up resistor to prevent unwanted resets.
5. Connect TX and RX to a serial converter or microcontroller UART pins for communication.
6. GPIO0 and GPIO2 can be used for custom functions and must be pulled high for normal operation.

• Ensure that the power supply can deliver sufficient current for the module's operation.
• Use a 3.3V logic level for UART communication to avoid damaging the module.
• Avoid powering the module directly from a 5V source without a voltage regulator.
• For stable operation, it is recommended to use an external antenna if the signal strength is weak.
• When programming the module, GPIO0 must be grounded to enable the flash mode.

• Module does not power on: Check the power supply and connections to VCC and GND.
• Cannot connect to Wi-Fi: Ensure the antenna is properly connected and the Wi-Fi credentials are correct.
• Serial communication not working: Verify the baud rate and that TX/RX are not swapped.

• If the module is unresponsive, try a hard reset by pulling RST to GND momentarily.
• For power issues, ensure that the power supply can deliver at least 250mA to the module.
• Use external level shifters if interfacing with 5V logic microcontrollers.

• Q: Can the ESP8266-01 be used with Arduino? A: Yes, it can be interfaced with an Arduino using serial communication (UART).

• Q: How do I program the ESP8266-01? A: The module can be programmed using the Arduino IDE or other development platforms that support the ESP8266.

• Q: What is the default firmware on the ESP8266-01? A: The module typically comes with AT firmware for basic Wi-Fi and networking commands.

#include <SoftwareSerial.h>

// RX, TX pins for connecting to ESP8266-01
const int RX_PIN = 2;
const int TX_PIN = 3;

// Set up a software serial port
SoftwareSerial esp8266(RX_PIN, TX_PIN);

void setup() {
  // Start the software serial communication
  esp8266.begin(115200);
  Serial.begin(115200);
  
  // Send AT command to check if the module is responding
  esp8266.println("AT");
}

void loop() {
  // Check if the module has responded with "OK"
  if (esp8266.available()) {
    String response = esp8266.readString();
    Serial.println(response);
  }
  
  // Check if there is any data from the Serial Monitor
  if (Serial.available()) {
    String command = Serial.readString();
    esp8266.println(command);
  }
}

Note: This example assumes that the ESP8266-01 is already configured to the correct baud rate and is in a state to accept AT commands. If you are using a different baud rate or need to change settings, adjust the esp8266.begin(115200); line accordingly.