This is my submission for the Make-to-Learn Youth Contest:
What did you make?
I made an old style analog VU meter and Clock using 2 analog panel meters, an Arduino, a real time clock, and other simple components. How it works: The unit plugs into a standard 3.5mm speaker jack. The Arduino reads the sound levels and converts it into electric pulses (PWM) to control the analog meters. When no sound is detected, the unit automatically changes to Clock mode and displays the time which is read from the real time clock circuit.
How did you make it?
I got the idea to make an analog VU meter from seeing them used in older audio receivers and amplifiers. I was always intrigued by the effect of a needle “dancing” to the beat of music. With my basic knowledge of electronics and the Arduino platform, I decided that I could make one myself. After searching around the internet to see if anyone had done anything similar, I found that many people create Clocks with analog panel meters. Well, why not include both functions?
Where did you make it?
I made this at home by myself. I like to listen to music a lot and I am always tinkering and playing with electronics. I thought that this would be a fun project to compliment my speaker system which I also built myself.
What did you learn?
I learned a lot from this project. The hardest thing to get right was the programming. I have never worked with analog panel meters before, so getting them to display time and sound accurately was challenging. For example: It was hard to get both meters to point exactly straight up at 6:30. I also learned that connecting the Arduino directly to an audio source can distort the audio. To fix this, I added some resistors and the distortion went away.