Breaking News
Comments
Oldest First | Newest First | Threaded View
Page 1 / 2   >   >>
David Ashton
User Rank
Blogger
Nice chip
David Ashton   7/8/2014 5:01:43 PM
NO RATINGS
That is certainly a neat little chip Max.  I would have preferred a  few more frequency bands but  really for a display that would probably be overkill.

However that leads me to my question...with only 7 frequency bands and 2 channels will your BADASS display now only have 14 channels instead of the 16 in the diagram?

I guess having sampled all 7 bands you could interpolate between adjacent values to get more "Pseudo" channels....?

Rcurl
User Rank
Rookie
Re: Nice chip
Rcurl   7/8/2014 5:48:59 PM
NO RATINGS
@David: "However that leads me to my question...with only 7 frequency bands and 2 channels will your BADASS display now only have 14 channels instead of the 16 in the diagram?"

I notice that you can set the oscillator frequency of the chip externally. I wonder if you could intentionally skew the oscillator frequency of a second chip being fed the same audio input to get some extra bands in between the intended ones? 

David Ashton
User Rank
Blogger
Re: Nice chip
David Ashton   7/8/2014 6:10:38 PM
NO RATINGS
@Rcurl....nice idea.  I saw a similar thing done recently with the good old LM3915 LED level meter chips to give 1dB increments instead of the usual 3dB.    And I got some chips that generate and provide a notch filter for 2600Hz tones used in Radio keying systems, I was going to underclock them to get the notch down to 1000Hz.  However in this case, according to Max's diagrams, the bands are fairly wide anyway, so I don't know if you'd really gain much here?

Max The Magnificent
User Rank
Blogger
Re: Nice chip
Max The Magnificent   7/8/2014 6:19:55 PM
NO RATINGS
@David: I would have preferred a  few more frequency bands but  really for a display that would probably be overkill

I agree -- the more the merrier -- even just one more would have been ideal for my purposes, but we're engineers -- we have to make do with what's available LOL

Max The Magnificent
User Rank
Blogger
Re: Nice chip
Max The Magnificent   7/8/2014 6:20:52 PM
NO RATINGS
@Rcurl: I notice that you can set the oscillator frequency of the chip externally. I wonder if you could intentionally skew the oscillator frequency of a second chip being fed the same audio input to get some extra bands in between the intended ones?

Oooh -- that is an interesting idea...

 

Max The Magnificent
User Rank
Blogger
Re: Nice chip
Max The Magnificent   7/8/2014 6:23:27 PM
NO RATINGS
@David: However that leads me to my question...with only 7 frequency bands and 2 channels will your BADASS display now only have 14 channels instead of the 16 in the diagram?

Thsi is something I've been pondering -- I think interpolating between two channels to create an additional channel would give me a quick fix. Of course, when I move onto doing all thus in software using an FFT (or similar algorithm), I'll be able to split things up into as many "buckets" as I wish.

 

jambrose950
User Rank
Rookie
Re: MSGEQ7 Nice chip
jambrose950   7/9/2014 12:51:31 PM
NO RATINGS
Yes, you can adjust the 33 pF and 200 kohm RC values to achieve different clock frequencies. However the filters are quite wide, so the effect would be minimal.   Others have found the interpolation technique  in firmware gives better results. 

jambrose950
User Rank
Rookie
Re MSGEQ7: Nice chip
jambrose950   7/9/2014 1:00:41 PM
NO RATINGS
We (Mixed Signal Integration) also have a 1/6th octave Low Power Spectrum Analyzer IC; the MSLSA.  The outputs are 6 AC outputs and you can easily cascade the devices.  Here is a link:

http://www.mix-sig.com/index.php?option=com_content&view=article&id=128:mslsa&catid=52


Samples and evaluation boards are available.  

Max The Magnificent
User Rank
Blogger
Re: Re MSGEQ7: Nice chip
Max The Magnificent   7/9/2014 1:13:50 PM
NO RATINGS
@jambrose: We (Mixed Signal Integration) also have a 1/6th octave Low Power Spectrum Analyzer IC; the MSLSA.  The outputs are 6 AC outputs and you can easily cascade the devices.

Very interesting -- I'm printing off the datasheet as we speak...

rheslip0
User Rank
Rookie
Re: Re MSGEQ7: Nice chip
rheslip0   7/9/2014 2:02:54 PM
NO RATINGS
Another approach - use the Teensy 3.1 and audio shield from pjrc.com. You only need one processor which is Arduino compatible so you can use the Neopixel libraries. They have a really nice audio DSP library including up to 1024 bin FFTs for the ARM M4 core. Teensy board about $20, audio sheild about $15. It will blow the doors off your solution:

https://www.youtube.com/watch?v=CblOUmK3oKM

I'm not associated with PJRC but I am very impressed with their products. I beleive they also have a high performance LED strip driver too.

Rich H

 

Page 1 / 2   >   >>


Most Recent Comments
EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Dr. Duino Diagnostic Shield Deduces Dilemmas in Arduino Shield Stacks
Max Maxfield
8 comments
As you are probably aware, I'm spending a lot of my free time creating Arduino-based projects, such as my Inamorata Prognostication Engine, my BADASS Display, and my Vetinari Clock.

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
20 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
15 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
46 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)