Monitoring Volume Level Application - End of Project Presentation Made by: Roi Abecasis Maxim Meltsin Supervisor: Boaz Mizrahi

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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 algorithm Goal: -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,…,20 2. Averaging samples as follows: new avg = new sample + old avg 3. Throwing samples which are below certain value

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 Protocols NEC: 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 demonstration Universal 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