Arduino based DC Voltmeter (0-50 volts)

In this post, we are going to make digital voltmeter using arduino uno. It's a DC voltmeter and it's range is 0 to 50 volt. As we know, arduino is an open source hardware prototyping platform used worldwide by the hobbyists, educators and students across the globe.
This is a handy voltmeter.

Stuff required:

1. Arduino uno
2. 16*2 lcd
3. 10k pot
4. voltage source

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.