How to enter AT mode in HC-05 bluetooth module

Using HC-05 in AT mode

Hello guys, In this post we will cover how to change password, name or mode (master or slave) in HC-05 module. 

Things required:

1. Arduino Uno board

2. Jumper wires

3. HC-05

4. Little bit patience :p

Note: Use can USB-TTL instead of arduino uno board. In this case, arduino uno board is simply used as USB-TTL converter.

Steps to follow:

First of all, upload a blank program to arduino.

/* Arduino Program */

void  setup(){

}

void  loop(){

}

Password protected system with AVR using DTMF

Password protected system using DTMF

Hello guys, this project is about password protected system using DTMF module. By using a predefined number we can make output either high or low by using the three digit code.
The codes can be changed in the program.

Components required:

• Atmega 16A
• USBasp programmer
• AVRdudes (for burning hex file)
• AVRStudio 4
• Compiler used: GCC
• DTMF module
• 3.5 mm audio jack

FOR OUTPUT LOW CODE IS str1="248"

FOR OUTPUT HIGH CODE IS str2="842"

Connections are as follows:

Q0-PD0

Q1-PD1

Q2-PD2

Q3-PD3

Output is from: PB0.