Frequency analyzer built from the new Stellaris Launchpad

Here’s the first project we’ve seen for the new Stellaris Launchpad. It’s a frequency analyzer which displays a graph on an 8×8 LED module. What’s that you say? You haven’t received your new Launchpad board yet? Neither have we since they don’t start shipping until the end of the month. But [EuphonistiHack] works as a software dev for TI and snagged one of the early development units.

Hardware is rather simple. He uses an OpAmp to feed audio from his laptop to the ARM processor. The 8×8 LED module is an MSP430 booster pack that is addressed via SPI. On the software side of things he’s really taking advantage of hardware peripherals to simplify his work. A timer triggers each ADC reading which in turn writes the values using uDMA. Digital Signal Processing (available as a CMSIS library for many ARM chips) is then used to translate the ADC value to one that can be displayed on the LEDs. Check out the video after the break to see the final version.

The Hackaday writers are looking for an easier name for this hardware than “Stellaris Launchpad”. It doesn’t seem to lend itself to a shorter name, like RPi or Raspi does for the Raspberry Pi. If you’ve got a catchy nick name for the new board please share it in the comments.


  1. Clint says:

    stell-pad or s-pad

  2. TopCat201 says:

    I was thinking StlPad but I like stell-pad better.
    Good thinking

  3. nullsub says:


  4. Mike Szczys says:

    I’m going to end up wishing we had a voting system for comments….

  5. BobFeg says:

    Just call it Stella.

  6. jasonstapels says:

    MspPad, PiccoPad, StellaPad,

  7. Beat707 says:

    Indeed, Stella is superb! Specially if you yell it like “Steeelllaaaaaa!!!!” :-p

  8. Zeke says:

    How about The Scratchpad?

  9. Ren says:

    Okay, I see on [EuphonistiHack]‘s blog that he isn’t using the microphone (plainly visible) on the bottom of the 8×8 display. As I was wondering why he needed to use a laptop to supply the audio signal, and I guess he’s not that far along, or the onboard microphone isn’t good enough.

    • DanJ says:

      I think the answer is because he’d have to implement an amplifier to take the low microphone level and get a line-level signal that he feeds his level-shifter/driver for the ADC. Easy enough to do but his real interest is in showing off the capabilities of the uP and he probably prioritized his time there.

    • Jordan Wills says:

      I probably should have mentioned this in my writeup, but in short, I didn’t like the microphone very much. I was never able to find a datasheet for the microphone itself, but in just playing around with it, it appeared to not be very sensitive. Also, the signal appeared to be fairly high impedance. I figured that if I was having to wire up a custom circuit to condition the audio, I might as well just abandon the on-board mic and use a generic audio source.

      I think I could probably add a few resistors to the hardware conditioning circuit to implement an amplifier with a controllable gain, but that idea didn’t sound too interesting, so I skipped on it (for now).

  10. zee says:

    It’s pretty obvious:

    MSP-EXP430G2 = Launchpad.

    MSP-EXP430FR5739 FRAM board = Fraunchpad (commonly referred to this within the community)

    Stellaris EK-LM4F120XL = Staunchpad.

    Per Merriam-Webster:
    adj \ˈstȯnch, ˈstänch\
    Definition of STAUNCH
    a : watertight, sound b : strongly built : substantial
    : steadfast in loyalty or principle
    — staunch·ly adverb
    — staunch·ness noun
    See staunch defined for English-language learners »
    Variants of STAUNCH
    staunch also stanch
    Examples of STAUNCH

    She is a staunch advocate of women’s rights.
    He’s a staunch believer in the value of regular exercise.
    I’m one of his staunchest supporters.

    • Ren says:

      Yeah, I like StaunchPad too, but it might get the lawyers at ST excited.

    • Galane says:

      Staunchpad was my thought too.

    • Galane says:

      How does this compare to the other cheap board TI is selling that has a socket for programming and using different devices?

      That one enables programming a chip then using it in other projects. With this one you’re stuck with the entire board, whether or not your project needs all its features.

      Much cheaper than an Arduino though.

      • Jordan Wills says:

        Galane, there’s a pretty huge difference between the msp430 launchpad and the stellaris launchpad. As the names might suggest, the two are different product lines that are aimed at different markets. As far as differences that you as a developer will care about, I figure there are three main areas.

        For one, the Stellaris uC’s tend to have more heavy duty peripherals in the silicon. The upside is more functionality, but the downside is more power draw.

        Two, the processors are different. The MSP430 uses a 16 bit processor, whereas Stellaris controllers can use either the ARM Cortex M3 or M4 processor (both 32 bit). Again, this lets the 430 runs with lower power, but the M4 on the Stellaris allows for some pretty nifty functionality, like hardware floating point support, which makes doing DSP stuff much quicker :)

        Three, the software libraries are different. This is the area I know the least about due to the fact that I haven’t done a project on an MSP430 in about two years now, but the software libraries are different. I’m incredibly biased, so I wont make any value statements about which is better, but suffice to say that the MSP430 software libraries are written and maintained by a different team of developers than the Stellarisware library.

    • Orpheus says:

      Call it a physician’s bias, but ‘staunchpad’ sounds like an emergency bandage for massive bleeding. You listed the adj defs, but the VERB ‘staunch’ means “to stem the flow of a liquid, usu. blood”

  11. dbear says:

    I thought of Stella too. It gets my vote.

  12. BobFeg says:

    Staunchpad sounds like a heavy flow days product.

  13. Willaim says:

    Stellaris LP is the only thing that sounds right to me.

  14. eric says:


  15. eric says:


    what’d i win?

  16. weesuzi says:


  17. weesuzi says:

    or Starpad

  18. bravocharlie says:

    1 for Stella

  19. Jordan says:


  20. Ben says:

    Why not Stelipad? Like helipad.

    Also instead of Staunchpad, Slaunchpad.

  21. raynor says:

    If the MSP is a launchpad then the Stellaris has to be at least a spacestation.

  22. zygomatic says:

    Stellaris LaunchPad => S.L.P.

  23. Agree with the name, StarPad.

  24. n0lkk says:

    IMO stanch or even stanchpad hasn’t very much in common with the actual name of the product to covet that the Stellaris Launchpad is the subject

  25. wntrmn says:

    upvote for Stella.
    (who is, hopefully, not a cheap girl…)

  26. Tim says:

    Stella is short and cool

  27. Suki says:

    yes, we all can’t wait to fool around with Stella

  28. Coda says:

    “Video after the break” is where? Or did my adblock plugin snarf it?

  29. crenn says:

    How about ARMPad? ;P

  30. anglophony says:

    I would think that such a stellar performing bitof kit would be called a “STELLARPAD “

  31. wilson skataaloot from across the street says:

    how about we call it Stella-pad-pad? then we could call it pad-pad for short!

  32. Tim says:

    Shipping at the end of the month? You’re lucky, mine’s not shipping until mid October!

  33. mharkus says:

    how about joojoo3 :D

  34. Dave says:

    How about StellaLP – catchy, short and distinctive! :)

  35. micko says:


  36. vinodstanur says:

    Call it STELLi……….

  37. Jordan Wills says:

    For what it’s worth, my vote’s for Stellaunchis :)

  38. chango says:


  39. freakwentc says:

    Stellar LP? StelLP? StLP? StlrLP? StlrPad? Whatever.

  40. bb says:

    st(tripple L)p
    st(cubed L)pad
    (it’s getting late)

  41. Tjay says:

    Can someone answer answer two newb questions about the circuit?

    1) By my reckoning, the cap tied to the AC signal should have a capacitance more along the lines of 10uF rather than 1uF. Is this a mistake in his schematic? The schem shows two 1uF caps, but it’s clear from his pic that he’s using two different kinds.

    2) This raises the question: Why did he tie a cap to the V+ on the op-amp?

  42. WillWill56 says:

    Stellaris LAunchPad = SLAP or SLaP?
    The TI SLaP!
    (The $5 price was a nice SLaP in the face ;) )

  43. Trollics says:

    Cal it Stormageddon, dark lord of the universe, or Stella LP if you must.

  44. satacable says:

    How about calling it the Stellaris Launchpad? I don’t think any shortage of text storage space or difficulty in speaking it necessitates shortening it further.

  45. halherta says:

    How about Stellicious

  46. 350X says:

    StellaPad Dry for regular coding.

    StellaPad Extra Dry for heavy coding.
    [25% more capacity]

  47. Dan says:

    You want short, just call it “S”. Long: Stellaripad

  48. Maulik Patel says:

    Hello There I am trying to do something similar, I wish to know 2 things, 1) I cannot get my ADC triggered by the Timer so could you please tell me how did you setup both ADC and Timer that they trigger each other. And The other thing is I cannot get CMSIS compiled on my PC. I would appreciate it if you could tell me how I can compiled CMSIS lib for Stellaris Launchpad LM4F120; my email id is just in case if you wish to reply me

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