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Max's BADASS Display, Part 1

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Aeroengineer
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fft's are great!
Aeroengineer   4/8/2014 10:44:31 PM
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Max,

What you want to do is run an fft.  This will ourput a real and imaginary component.  You will want to get the magnitide of this be taking the square of the sum of squares.  This is assuming that you already have the data in digital format.  I forget why, but you get a mirroring effect, and because of this, you can cut out the last half of your data when you go to display it.  you can also use a moving window buffer to process your data from, or just a fixed rate type buffer.  This would be once the buffer got full, you then do the fft.  Fft's are very computationally expensive, so you cannot do them that fast.  You kight be looking at 1-10Hz depending on number of points.  Oh and you want your buffer to be as big as the number of points your fft is, or if smaller you will want to zero pad it.

That falling dot is just the peek of the fft in that bin.  You just jave it fall at some programmed interval, and reset once that value has been exceeded.

 

All this that I passed onto you is somewhat theoretical.  I was looking to use this method for my rf project when I realized that I could not perform the calculation fast enough.

 

 

  

Max The Magnificent
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Re: fft's are great!
Max The Magnificent   4/9/2014 8:00:44 AM
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@Aeroengineer: What you want to do is run an fft.

A Fast Fourier Transform (FFT) is certainly one option, but -- as you say -- it is computationally expensive -- espectially if all you have to play with is a 16MHz Arduino Mega with only 8KB of SRAM (sad face).

Happily, there are other alternatives (said Max (a) mysteriously and (b) as if he knew what he was talking about LOL).

Wait for Part 2 of this mini-series when all will (probably not) be revealed :-)

 

David Ashton
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Dot/Bar Peak/Average displays
David Ashton   4/9/2014 4:25:40 PM
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@Max...being an old-school guy (Read: old fart) I would use a bunch of LM3915 dot/bar display drivers.  You'd then have to get a bunch of narrow band or notch filters, one for each frequency.  This would wind up being a considerable number of IC's, though you might me able to mux some of it....... so Aeroengineer's idea of FFTs is probably the better way to go (and that way you could probably work an FPGA into it as well....)

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/9/2014 4:47:49 PM
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@David: You'd then have to get a bunch of narrow band or notch filters...

Funnily enough, this was (maybe still is) one of my original thoughts ... just wait toll you see Part 2...

Aeroengineer
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Re: Dot/Bar Peak/Average displays
Aeroengineer   4/9/2014 5:07:17 PM
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Just roll it out already!!! ;)  I was going to say, the other way would be to do a series of bandpass filters in software.  Because you are not looking for anything too sophisitcated, the filters do not need to have very high Q, and they could blead all over one another.  Or you could go with a Cortex M4 part and be done with it.  You know you want to!  I think that there is a Cortex M4 part that is Arduino compatible.

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/9/2014 5:24:35 PM
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@Aeroengineer: Just roll it out already...

It's coming .... it's coming ...

I thought that comment at EE Live! was good -- the one about you being a mechanical engineer who was doing electronics, while at the same time you are an aerospace engineer who is building submarines LOL

Aeroengineer
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Re: Dot/Bar Peak/Average displays
Aeroengineer   4/9/2014 5:26:42 PM
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Yeah, I kind of have my hands into a lot.  You were also very complimentary of my skills.  I still have a long way to go.  Tonight, I will be setting up a function to enable my Gyro/Accelerometer for my receiver project.

 

Looking forward to the rest of your project.

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/9/2014 5:28:33 PM
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@aeroengineer: You were also very complimentary of my skills.

You ought to hear what I say behind your back LOL

Aeroengineer
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Re: Dot/Bar Peak/Average displays
Aeroengineer   4/9/2014 5:29:51 PM
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There you go bursting my bubble of euphoria ;)

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/9/2014 5:42:39 PM
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@aeroengineer: There you go bursting my bubble of euphoria...

It wasn't me -- I never touch other peoples' euphoric bubbles (not since ... the incident!)

David Ashton
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Re: Dot/Bar Peak/Average displays
David Ashton   4/9/2014 5:16:20 PM
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@Max... "just wait toll you see Part 2..."

We have to PAY for it??

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/9/2014 5:22:48 PM
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@David: We have to PAY for it??

How much do you want to see it? LOL

SandorD
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Re: Dot/Bar Peak/Average displays
SandorD   4/9/2014 7:49:36 PM
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What got me here is the link in the emailed newsletter from ubmtechelectronics.com. It was promising me "Max's MADASS Display, Part 1". Following the link, I've found "Max's BADASS Display, Part 1", instead. I feel slightly cheated but very much intrigued!

I need to know, @Max, do you have both MADASS and BADASS displays? Have the design specifications changed? Are you playing the old MADASS/BADASS switcheroo on us? Or, shock horror, have you been censored?!  :-o

 

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/10/2014 10:38:11 AM
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@SandorD: I feel slightly cheated but very much intrigued!

Hi there -- thsi was my bad -- I started out with Max's MADASS Display, where MADASS originally stood for "Magnificent Acoustic Diagnostic Astoundingly Superior Spectrometric"

But then I started to think that if we ever got to say "Max The Magnificent's Magnificent Acoustic ...." ... it would sound a bit silly ... also I didn't really like the "Spectrometric" part ...

So I changed it to Max's MADASS Display. where BADASS stands for "Bodacious Acoustic Diagnostic Astoundingly Superior Spectromatic"

This means we can now say "Max The Magnificent's Bodacious Acoustic Diagnostic Astoundingly Superior Spectromatic Display" without sounding silly at all (LOL)

 

 

SandorD
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Re: Dot/Bar Peak/Average displays
SandorD   4/10/2014 7:02:49 PM
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Whew! Mystery resolved, I can sleep again. Thanks @Max! :-)

khaynes
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Re: Dot/Bar Peak/Average displays
khaynes   4/10/2014 8:27:40 PM
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Hi Max,

A lab partner of mine and I built one of these things in 1978.  It was about 24 X 36 inches.  The bulb spacing was about 0.75 inch and the front to back spacing was about an inch.  We connected it to a 5 channel color organ and had a blast playing with it.  We got some interesting effects by move the top or bottom closer to the back.  Give it a shot.  Good luck, Kim

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/11/2014 11:10:30 AM
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@khaynes: A lab partner of mine and I built one of these things in 1978.  It was about 24 X 36 inches.

Wow -- 1978 -- I bet this was a real attention-getter back then -- do you have any photographs?

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/11/2014 11:02:38 AM
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@SandorD: Whew! Mystery resolved, I can sleep again.

LOL

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/10/2014 10:39:22 AM
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@SandorD: Are you playing the old MADASS/BADASS switcheroo on us?

If only I had a coconut for every time someone has done this to me... LOL

 

Rcurl
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Re: Dot/Bar Peak/Average displays
Rcurl   4/9/2014 10:18:39 PM
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I wonder what would happen if you took the LED outputs from this PIC Color organ:  http://www.protonbasic.co.uk/content.php/3435-Colour-Organ-using-a-fast-8-bit-FFT-routine  which uses FFT and fed it into 8 LM 3915's?

Max The Magnificent
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Re: Dot/Bar Peak/Average displays
Max The Magnificent   4/10/2014 10:44:34 AM
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@Rcurl: I wonder what would happen if...

Hi Rick ...interesting... I was planning on writing Part 2 today, but I finished my Infinity Mitrror last night, so I'm going to post a blog and video on that sometime today, and I'll do Part 2 of the BADASS display tomorrow -- then maybe you and I can chaton the phone (when are you next going to be back here in Huntspatch?)

Rcurl
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Re: Dot/Bar Peak/Average displays
Rcurl   4/10/2014 11:11:38 AM
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@Max: when are you next going to be back here in Huntspatch?

Actually, I was in Madison last Wednesday to tour STI Electronics (VERY interesting place!), but word of my trip must have been leaked in advance because I saw that you slipped off to the Left Coast just before I passed through.

I'm looking forward to seeing the Prognistication engine, the BADASS display, and the Infinity Mirror (and other heretofore unknown wonderful stuff) soon! 

 

ClarkeMonroe
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$200!?
ClarkeMonroe   4/10/2014 3:57:27 PM
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I actually saw that same vertical boombox with LED spectrum at the San Jose airport when I was leaving EE Live and I'm shocked it was $200!  (Though, I am not shocked that the punk working there was too self absorbed to even make eye contact with you.  Haha.  Just so you know, I'm 27 and I still find that incredibly rude.)  I'm glad to see someone move so swiftly from an idea to a project.  It seems to take forever before my projects get any traction. But I'm eager to see what hardware will be involved in whatever project you settle on.  My guess is 128 RGB LEDs, 2 Arduino Uno's, and 12 motorized potentiometers with aged-bronze dials.

Max The Magnificent
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Re: $200!?
Max The Magnificent   4/10/2014 4:03:10 PM
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@PapaSquat: My guess is 128 RGB LEDs...

Ha! I wouldn't even get out of bed in the morning for a paltry 128 RGB LEDs (LOL) ... just wait ... I'll be posting Part 2 tomorrow...

ClarkeMonroe
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Re: $200!?
ClarkeMonroe   4/10/2014 4:06:02 PM
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I'll give you $200 to tell me now!

Max The Magnificent
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Re: $200!?
Max The Magnificent   4/10/2014 4:30:12 PM
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@PapaSquat: I'll give you $200 to tell me now!

Have you asked your wife about this? LOL

pmcw
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Idea
pmcw   4/10/2014 6:29:51 PM
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How about doing a stereo design, but have each channel emanate from the far vertical sides towards the middle?  You could also have the color start become more intense or brighten as it nears the middle.  Low frequencies at the bottom and high frequencies at the top.  You could generally correlate the sound spectrum with the breadth of the light  spectrum - deep read to yellow, green, blue and purple for the highest audio frequencies with graduations bridging the gaps.

Max The Magnificent
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Re: Idea
Max The Magnificent   4/11/2014 11:08:59 AM
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@pmcw: How about doing a stereo design, but have each channel emanate from the far vertical sides towards the middle?

Funnily enough I have been thinking about going stereo. There are several ways to do this-- for example:

Having low frequencies on the left transitioning to high-frequencies on the right -- then having the left-channel on the bottom growing up (with intensity/volume) toward the middle and the right channel on the top growing down.

Or we coudl keep the low-frequency-left to high-frequency-right, buthave the left channel start in the horizontal middle growing down and th eright channel start in th ehorizontal middl egrowing up.

The great thing about having a bunch of LEDs and a microcontroller is that you can experiment with lots of different display styles.

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