Project: Spectrum – Final Touches/The End

Last time I showed the final frequency response of Spectrum. I guess now I need to show the finished thing!

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Project: Spectrum – PCB V1, a bit of a disaster

With all of the sub-systems developed on a breadboard I moved to the next step of designing and ordering the circuit board that I would use for the final product. For now, I will skip over the design choices and jump straight to what happened when I received the board and what the mistakes were and how I have changed my design.

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Project: Spectrum – Filter Design

Frequency Response

As I said in the previous post, I want my filters to perform in the same way as the MSGEQ7. The frequency response of this chip is given in it’s datasheet.


The 7 frequency band responses of the MSGEQ7

From the datasheet I can see that, to replicate this response, I will need 7 bandpass filters at 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz. Each filter will need a quality factor of 6 (this basically sets the bandwidth of the filter).

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Project: Spectrum – Beginning

It’s getting harder and harder to find spare time to work on projects. Firstly, the holidays at MIT are tiny compared to the holidays I get at Cambridge, and now that it’s finally Summer I am doing an internship which keeps me pretty busy 5 days a week, and I still want time to explore California and surrounding areas.

Anyway, I want to do a project that looks good and has some analogue electronics in it. I will build a system that listens to sound via a microphone, breaks the sound down into frequency bands and displays how loud each frequency band is using a strip of LEDs. It’s a similar idea to a Colour Organ but I want 7 frequency bands and 10 volume levels per frequency band (a total of 70 LEDs).

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