Monitoring Volume Level Application

- End of Project Presentation

Made by:Roi Abecasis

Maxim Meltsin

Supervisor:Boaz Mizrahi

Contents Table

• Previous Project• Project goals• Project milestones• System demonstration

The Previous Project

Multi-Sensors Personal Digital Assistant (PDA)

By: Aviv Rosenberg & Ben-Ami Zilber

The Previous Project

INPUTS:

OUTPUTS:

TOP LEVEL

Project Goals

• Automatic TV volume control• Keeping TV volume on given level• Detecting significant volume changes and acting

accordingly

• Implementation of Universal TV Remote Controller (optional)

Project Milestones

Part A: Microphone

• debugging microphone circuit • Processing microphone samples• Implementing an algorithm for AGC

Project Milestones

Part B: Infra Red

• Learning existing IR Protocols (RC5, NEC,..) • Detecting IR protocols frequencies• Implementing functions for decoding IR

messages • Implementing functions for transmission

The algorithmGoal:- Finding reliable and stable method to measure

volume level changes

Problems:- Overcoming sensitivity for short but intense

sounds- Avoiding ‘quiet’ samples- Typical TV Broadcasting volume is very inhomogeneous

The algorithm

Solutions:1. Measuring maximal value in time segment: new sample = max{sample(i)} , i=1,…,202. Averaging samples as follows:

new avg = new sample + old avg3. Throwing samples which are below certain value

(1 )

The algorithm

Implementation:1. calculating stable value by sampling and

averaging 2. Setting higher and lower thresholds values as

app. 2% higher and lower then stable average value

3. An act is taken whenever a deviation from threshold values is detected

The algorithm

Finding stable value

Sample

Start:Setting higher

and lower thresholds

New value < min >=increasing volume

New value > max >=decreasing volume

Otherwise do nothing

Two Main Infra Red ProtocolsNEC:

RC5:

f=38 kHz

f=36 kHz

Implementation of different IR protocols issues

• Different Carry Frequencies• Different ‘0’ and ‘1’ bit representation• Different Start Sequence• Toggle bit and repeat pulse• Different bits number

System demonstration

Universal Learning IR Remote Control

Automatic Control of TV volume

Throughout work

Presenting signal on screend

decoding:

PDA Respond for 1KHz sinus wave

System demonstration

National geographic channel:

Channel 2:

Channel 10:

System demonstrationUniversal Learning IR Remote Control

Automatic Control of TV volume

Resource Usage

CPU Usage:• About 0.3% for average volume detecting• About 1.1% in transmitting mode• Typical total average usage = 0.3%

Memory Usage: Less than 1Kbytes

Special Thanks to:

• Boaz Mizrahi – Supervisor• Bruria Zohar – Lab technician

THE END