Design with HC05 Bluetooth Module in Cirkit DesignerThe HC05 Bluetooth Module is a wireless communication device that allows for the transmission of data over short distances using Bluetooth technology. It operates on the Bluetooth 2.0 protocol and supports both master and slave modes, making it versatile for a wide range of applications. The module is commonly used in embedded systems, IoT applications, and robotics to enable wireless connectivity between devices such as microcontrollers, smartphones, and computers.
This circuit features an Arduino UNO microcontroller interfaced with an HC-05 Bluetooth module for wireless communication. It also includes two 5V two-channel relay modules, which are connected to the Arduino for controlling external devices. The setup allows for remote control of devices via Bluetooth.
Open Project in Cirkit Designer
This circuit consists of an Arduino UNO microcontroller connected to an HC-05 Bluetooth module. The Arduino provides power to the Bluetooth module and facilitates serial communication between the two devices, enabling wireless data transmission.
Open Project in Cirkit Designer
This circuit features an Arduino Nano interfaced with a BNO055 sensor and an HC-05 Bluetooth module. The Arduino communicates with the BNO055 via I2C (using A4 for SDA and A5 for SCL) and with the HC-05 via serial communication (using D0/RX and D1/TX for data transfer). The HC-05's Key and State pins are connected to D2 and D3 of the Arduino for module control, and all components share a common ground with the Arduino powered at 5V and the BNO055 at 3.3V from the Arduino's 3V3 output.
Open Project in Cirkit Designer
This circuit features a Raspberry Pi Pico microcontroller interfaced with an HC-05 Bluetooth module for wireless communication, an HMC5883L compass module for magnetic field measurement, and a GPS NEO 6M module for location tracking. The Pico is configured to communicate with the HC-05 via serial connection (TX/RX), with the compass module via I2C (SCL/SDA), and with the GPS module via serial (TX/RX). Common power (VCC) and ground (GND) lines are shared among all modules, indicating a unified power system.
Open Project in Cirkit DesignerThe HC05 Bluetooth Module is designed for ease of use and reliable performance. Below are its key technical details:
| Parameter | Specification |
|---|---|
| Bluetooth Version | 2.0 + EDR (Enhanced Data Rate) |
| Operating Voltage | 3.3V to 5V |
| Operating Current | 30mA (typical) |
| Communication Protocol | UART (Universal Asynchronous Receiver-Transmitter) |
| Baud Rate | Default: 9600 bps (configurable) |
| Range | Up to 10 meters (unobstructed) |
| Frequency Band | 2.4 GHz ISM |
| Modes | Master and Slave |
| Dimensions | 37.5mm x 15.2mm x 2.7mm |
The HC05 module has six pins, as described in the table below:
| Pin | Name | Description |
|---|---|---|
| 1 | EN (Key) | Enables AT command mode when pulled HIGH. Leave LOW for normal operation. |
| 2 | VCC | Power supply input (3.3V to 5V). |
| 3 | GND | Ground connection. |
| 4 | TXD | Transmit data pin. Sends serial data to the connected device. |
| 5 | RXD | Receive data pin. Receives serial data from the connected device. |
| 6 | STATE | Indicates the connection status (HIGH when connected, LOW when disconnected). |
The HC05 Bluetooth Module is straightforward to use and can be easily integrated into a circuit. Below are the steps and considerations for using the module:
VCC pin to a 5V power source and the GND pin to ground.TXD pin of the HC05 to the RX pin of the microcontroller.RXD pin of the HC05 to the TX pin of the microcontroller. Use a voltage divider if the microcontroller operates at 5V logic levels to avoid damaging the HC05.EN pin HIGH before powering the module to enter AT command mode.Below is an example of how to use the HC05 module with an Arduino UNO for basic serial communication:
VCC → Arduino 5VGND → Arduino GNDTXD → Arduino RX (Pin 0)RXD → Arduino TX (Pin 1) (use a voltage divider if necessary)#include <SoftwareSerial.h>
// Define RX and TX pins for SoftwareSerial
SoftwareSerial BTSerial(10, 11); // RX = Pin 10, TX = Pin 11
void setup() {
// Initialize serial communication with the computer
Serial.begin(9600);
// Initialize serial communication with the HC05 module
BTSerial.begin(9600);
Serial.println("HC05 Bluetooth Module Test");
Serial.println("Type a message to send via Bluetooth:");
}
void loop() {
// Check if data is available from the HC05 module
if (BTSerial.available()) {
char received = BTSerial.read();
Serial.print("Received: ");
Serial.println(received);
}
// Check if data is available from the Serial Monitor
if (Serial.available()) {
char toSend = Serial.read();
BTSerial.write(toSend); // Send data to the HC05 module
Serial.print("Sent: ");
Serial.println(toSend);
}
}
RXD pin.EN pin is HIGH before powering the module to enter AT command mode.STATE pin to monitor the connection status of the module.Module Not Responding to AT Commands
EN pin is HIGH before powering the module.No Data Transmission
TXD and RXD pins.Unstable Connection
Module Not Pairing with Other Devices
1234) matches the other device's requirements.Q: Can the HC05 module communicate with smartphones?
A: Yes, the HC05 can pair with smartphones that support Bluetooth 2.0 or higher. Use a Bluetooth terminal app to send and receive data.
Q: How do I reset the HC05 module to factory settings?
A: Enter AT command mode and send the AT+ORGL command to reset the module to its default settings.
Q: Can I use the HC05 module for audio transmission?
A: No, the HC05 is designed for serial data communication and does not support audio transmission.
Q: How do I change the module's name?
A: Enter AT command mode and send the AT+NAME=<desired_name> command to set a new name.
By following this documentation, you can effectively integrate and troubleshoot the HC05 Bluetooth Module in your projects.