Analog Noise Cancelling Headphones with Equalization and LED Matrix Display
This complex circuit was designed based on intuition gained from a semester of circuit design.
On a team of three, we split duties by creating a project with 3 separate modules to work in conjunction: and equalization circuit, a digital LED matrix display, and, and active noise-cancelling circuit.
I focused mainly on the noise cancelling system. I chose to make it in analog for a little more of a challenge that digital would be. In the physical headphones (industrial safety earmuffs), I inserted a mic and two headphone drivers. For simplicity, we were using a mono signal for the audio, thereby leaving one channel free in a standard stereo headphone cable. Making use of this, I made that channel the mic signal that was input into the cancelling circuit. This conveniently minimized cable.
On a team of three, we split duties by creating a project with 3 separate modules to work in conjunction: and equalization circuit, a digital LED matrix display, and, and active noise-cancelling circuit.
I focused mainly on the noise cancelling system. I chose to make it in analog for a little more of a challenge that digital would be. In the physical headphones (industrial safety earmuffs), I inserted a mic and two headphone drivers. For simplicity, we were using a mono signal for the audio, thereby leaving one channel free in a standard stereo headphone cable. Making use of this, I made that channel the mic signal that was input into the cancelling circuit. This conveniently minimized cable.
In the end, this ambitious project was mostly successful. However, even though I managed to refine the inverted signal of the outside noise (example shown at right), true sound cancellation was not quite achieved. I figured out how to make the frequency, amplitude, and even the latency adjustable, but the teaching staff did not have enough expertise in analog audio to help me improve upon what I already had.
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