According to Pete - June 2012 Edition


It's the first Monday of June, which means we have a new installment of "According to Pete" - our monthly segment with SparkFun Director of Engineering Pete Dokter. In this installment, Pete talks more about his audio project and our trip to Maker Faire Bay Area.

In case you want to see the "According to Pete" pin that he talks about in the video, check it out:

That's it for now! We hope you enjoyed the video. While we're at it, we've decided that we are going to amp up (pun intended) our "According to Pete" production. There will now be two "According to Pete" installments each month. So look for the next ATP in the coming couple weeks! As always, leave any questions or comments below. Cheers!


Comments 43 comments

  • There should be an ATP every Monday!

  • According to Pete: It’s not a rock.

  • Perhaps Pete is suggesting you can prevent Ground from floating by tying it to a rock?

  • Life needs a little stupid!

  • Best section in sparkfun by far. Can’t wait for the second part :)

  • Lab coats with the According to Pete logo??? :-)

  • You say the mp3 player runs at 3 volts. Why not bypass the booster circuit and power it from the 3.3 vout from the Arduino? Apart from not being as educational about regulators of course :)

    • I thought that also, but as small as those things are, I’m guessing it wasn’t worth the trouble to find and bypass.

      • Yep. The player is 2 boards at right angles to each other. Disassembling the thing and sorting the booster is just way more work than necessary.

  • This is my first time watching ATP. I really enjoyed it and now want more of it. I second the comment that there should be an ATP every Monday (It gives me something to look forward to in school).

  • “thank u lord!!giant robotic sub-woofer speaker out of the sky!!!can i now wish for a lamborgini….or a ferrari would be nice”

  • who let the giant sub-woofer out?……

  • Pete why did not you use the MP3 decoder shield or breakout boards instead of hacking an MP3 player.

  • also any legal way we can download the videos?

    • Realplayer can download videos from you tube. Now do you have permission to use them? You would have to contact Sparkfun.

      http://www.sparkfun.com/static/about scroll down a bit.

    • There are a few apps that will grab the video for you.

  • very interesting video! seems like pete is sort of having fun.. against his own will haha but yeah id love to see more videos! (weekly would be very cool!)

    one thing i am very unclear on though is what exactly is going on? i may have missed something, in fact i am pretty sure i did, as this is the first video i have seen. however, it would be cool if there was a little longer and more clear written abstract about the video. like for example what the project is so that a viewer like myself can pop in and get caught up to speed on whats going on (again this is the first acording to pete i have seen).

    also, a short verbal recap at the beginning could achieve this as well possibly easier for you guys (like 1 min or less maybe). additionally, a better title would be nice. the fact that sparkfun according to pete and the date is in the title distracts from the point of what this episode is about, which i am still not 100% sure what that is, and so yeah in my opinon it would be cool if you had a title like “pete hacks an mp3 player together with his amp project”.

    another small thing that would be really nice is if you could have a tab devoted to these “Acording to Pete” videos for better organization of the videos and just so they could be rewatched (again i do not know if you guys want to do this).

    another idea, I do not know if you guys have seen the MAKE podcasts, but i really like that format. And if that is what you guys are attempting to emulate here I would love to see that happen!! I visit this site more than I do facebook anymore and well thats saying something haha. I am always intrigued by the array of tutorials, tools, and supplies here, it is a fantastic resource!

    thanks pete! hope to see more videos coming, and am interested to see what your doing with the mp3 player and amp exactly. And I hope my ridiculously long comment had some helpful feedback for the video, and wasn’t too terribly annoying haha!

    -Nick

    • “really nice is if you could have a tab devoted to these “Acording to Pete” videos ”….

      Like this? http://www.youtube.com/playlist?list=PL9EF3C374FD903ACE&feature=plcp

      • i know, but i dont like how thats organized.. i should have been more clear i was thinking a tab like i said that had all the videos organized and numbered oldest to newest with an abstract and the ability to download the video..

    • Hi Nick,

      Much of that isn’t within my control, but I could have done a better job giving “the story so far”. Sorry about that, and I’ll try to do better. A new title? I don’t think they’re going to allow that. “According to Pete” sounds like I know what I’m talking about. I’d much prefer something like “Pete sticks his thumb in his eye and everyone laughs at him”.

      • oh ok, well whatever. this is still very interesting, and im catching up on all the old episodes, thanks for the awesome videos! i meant like new titles for each individual videos not the series title. haha thats a more interesting title for sure! haha

  • Last time I asked for moar Pete. This time I get moar Pete. Yay for moar Pete!

    • As was mentioned in the video: it’s not so much moar Pete, just distributed Pete.

  • pete needs to move the items around to show things better, and well the videographer just needs to adapt to that. If the videographer can’t adapt to things moving about as they need to, find a different videographer.

  • Hey pete. Just curious, why did you decide to gut an off the shelf mp3 player instead of using one of the handful of parts sparkfun sells? Would be a lot simpler to power and talk to than what you have now.

    • Covered last ATP. It seems the Sparkfun mp3 shields use things like weird filename structure.

      • Among other things, yes. I’d love to play with one of the MP3 players that we stock, but what I did was much easier and quicker.

        • Doesn’t that beg to make a call out to the SF fan base to find a MP3 Chip that does not have all the current handicaps? For the next SF MP3 break out board?

  • OK I’m really learning some stuff now that you done with the amp. How long have you been working on it 2 years? :-)

    But anyway leaned much from the interface with the mp3 player. I’m trying to hack together a time lapse wearable “life cam” using a 808 key chain camera and a attiny85 and need to interface two switches. I was going to use two transistors but now realize I don’t need them. The two switches go to ground so to fire them I just have to do the same as you did with the wires to ground. Also its all running off a single lipo so same voltage all around.

  • A TO-220 regulator seems a bit of overkill, especially as you aren’t pulling the minimum current for stability; try a T0-92 or similar small reg. Also, picking an order of magnitude (more or less, depending) smaller resistor value on your divider will draw that minimum current, so adding a minimum-load resistor isn’t necessary. Also, you might not even need the divider, as the 317 family has a minimum 1.2V output, if the MP3 player can run from a rechargeable battery (1.2V NiCd or NiMH). Then you would only need the load resistor and bypass caps, reducing external component count by half (to 3). With a smaller reg, even the load resistor might be unnecessary. :-)

    • Right on all counts. But you’ve got to remember that this isn’t necessarily about best practices. It’s more about doing what you can with what you have. That LM317 came out of a drawer full of used junk, and it had come off of something else.

  • well, very personable . Should have a how to TV program somewhere selling something or he should be selling something here but it is a big time waster with little real useful knowledge imparted at the moment. Whats the point here?

  • IS THAT A SHIRT BUTTON?

  • Any way you can index them by subject or otherwise make them better searchable? I saw something on one a while ago which I was trying to find again recently. And short of watching one after another… I couldn’t come up with an easy way to get there.

  • Hi Pete, was that a Jackson guitar? It looks great! Thanks for the video.

  • So is there any reason why you’d use a voltage regulator and not a Voltage Divider? or would there be too much noise in the Vs channel for the MP3 player to run properly if it was direct Vs voltage?

    • As the Dok mentioned, it’s because the voltage will change based on current draw of the device, especially since the current draw of an MP3 player isn’t constant.

      This tutorial explains it in more detail. Search for the phrase “Another little gotcha for beginners”, it’s about 1/3 down the page.

    • Yeah… you can’t do that. I mean, you can, but you won’t want to. By drawing current from that node, you’re effectively lowering the resistance of the lower resistor and changing the voltage at that point. No regulation at all.

    • The reason you don’t use a voltage divider is that the load through the MP3 player varies. Think of that load as a second resistor between the divider output and ground. When the MP3 player is pulling more current, that effective resistance is smaller, which is going to reduce the voltage.

      The reason the divider works with the regulator is that the adj pin is high impedance, meaning hardly any current is flowing through it.


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