According to Pete


In this month's edition of "According to Pete," we're revisiting a project from the past. You may remember the edition where Pete took us to his home workspace and talked about his DIY audio amplifier - well, in this month's post Pete is revisiting that project and going a little bit deeper. Check it out:

There you have it, folks. As always, feel free to leave any questions or comments below and we'll do our best address them - and stay warm out there (currently sitting at about 4° F outside here in Boulder). Cheers!


Comments 36 comments

  • Wow, don’t know if it’s been said but the quality of the video and the editing gets a thumb waaaay up! What camera you using and which editing software?

    • I was thinking the same thing. Well done, Gregg.

    • Also, the lighting is improved.

      • I’m guessing he’s using a softbox …. but ya, the lighting is the first thing that impressed me.

        • I suggest moving the key light further to one side of the camera to cut down on the glare from the glasses (it will also introduce some modeling of detail through shadows, enhancing the 3d effect). 80F in Fla today.

          • I whole heartedly agree. The quality of the video is just great and it was the first thing I noticed. Having just gotten a 5D, I can certainly believe it a capable camera.

            Also have to agree the light isn’t in the best spot. If nothing else, it could use some added height if that’s at all possible. Maybe bounce it off the ceiling (assuming it’s white)?

    • Gregg (our video guy) will be happy to hear that! I believe he primarily uses a Canon 5D (with a few different lenses) and Final Cut Pro.

  • Pete,

    Have you considered using WiFi instead of the XBee gateway? I ask because I’m not sufficiently familiar with the XBee gateway, I’ve always just used the WiFi (Using the WiFly shield.)

    Heh, your amplifier would totally go up to 11 if you managed to find an excuse to integrate a Linux computer into it. Giada makes a sweet little machine that would be totally over the top. With that, you could run Processing to generate a GUI for your amp and everything.

    • Well, XBees may become scarce in the next few months, so I may have to use something else, don’t know yet. The Linux thing will have to wait for another time. My schedule for the next 5 months is filling up fast.

      • XBees scarce? Is there something I should know?

        • I wondered the same thing… On the product page it says quote “Note: Due to recent flooding in Thailand and the subsequent damage to the Digi factories, there may be long lead times on all XBee products and shortages until they recover from the damage.”…Sooo… Thats what you should know.

      • One nice thing about WiFi is that your smart phone already supports it. It’s easy to download a Telnet App and make a fast text parser on the Arduino so you can send commands to it.

    • Last Modified 3:00 PM Monday Action: +1’d. Reason: Mention of awesome Linux thing.

  • FYI I was a video editor for years, and this was, if not classical editing, quite well done. And audio was great- always a major plus! Kudos! Rory McDonald Asciirory@gmail.com www.trainingconductors.com

  • Pete O. may be about to push the envelope on DIY amplifiers.

  • The display will potentially have its own power supply… heh heh

  • Just an idea, prisms. Insted of buying 800 lasers, get a few and make them go into prisms. It will make them keep an angle relation between them, but I don’t really think you care about that :P

  • Pete, Have you considered using the voxel shield (www.mushroo.me/home/voxel-shield) for controlling the display. You can use the voxel shield to control 512 LEDs, so you can make an 8x8x8 LED cube, or a 32x16 visualizer display. Email me if you have any questions.

  • How about a Chumby for the display? What is the goal of the display- just control and Spectrum analyzer? Just postulating…

    • Spectrum and VU. But I don’t want to just use a monitor. That would be boring. I’ll hash this out a bit more in the next video.

      • Surely this isn’t boring? Maybe a bit loud and complicated, but very fun, and with some creativity, it could be used as a spectrum display and VU meter.

        • Boring? Not in the slightest. Pretty damn cool, actually. But small, and yeah, noisy. I don’t want something competing with the music.

  • This project looks similar to a project I did for my senior design. There’s documentation on my website:

    http://www.luckyohm.com/lucky_ohm/stereolith.html

    Some interesting bits for you might be the “digital pots” that we used from TI. You could use these to control your volume if you wanted. Or, you could try an Alps motorized pot. These are expensive but super cool.

    We used RF, which was kind of a pain. If you’re on Android, you could use Bluetooth with the Amarino toolkit. Its pretty righteous.

    Good luck, keep us posted!

    • Digital pots? Where’s the fun in that? And the faders that I’m going to use are already motorized.

  • If I were Pete, I would use the 2560 for more code space and I/O’s. I would use a Touch screen LCD for the Display driven by a GAMEDUINO SHIELD. Not sure about the XBEE and X2. I would probably prefer a RN-XV WiFly or if wired is an option, an Ethernet Pro or the POE Shield. I would use an ATX PS for simplicity and availability. We all have a few of those laying around. The key here is the Touch Screen LCD for control and display the bouncing EQ, I know he wants that! The Wired or Wireless network to pull MP3 from the house Server. Of course with the 2560 you can continually addon. Theres my 3 cents worth. Have Fun Pete. We do it cause it’s Fun and We can.

    • I’d stay away from ATX supplies for audio, as the cheaper ones tend to have a lot of noise on the power rails, which can find its way into the sound. I think Pete even mentioned this in an earlier According to Pete. Everything else you mentioned, I would love to do if I had the money, particularly the network media access.

  • Pete- I would not do the laser, for one you’re going to have to have something to reflect that light off of. Unless your garage is really dusty or you have some type of fog machine I think your not going to see anything.

    • I wouldn’t be relying on the air to make them visible, I’d be using walls.

      • You could hack one of the assemblies that are inside laser printers to make a raster scan laser display with a lot of work.

        You also could use a laser pico projector.

        Or just stay with the tried-and-true multisegment led bargraph VU displays.

    • What about DJ Lasers (sometimes I call them LAYZORS!!!1111!!!11!!1!!!! :D) which aren’t actually lasers?

      • “Aren’t actually lasers”? Maybe you’re used to cheaper FX, because all of the party/rave laser systems I’ve seen use real LAYZORS(and they’re expensive for it). Example. :D

        • Well, aren’t LAYZORS that are powerful enough to have the beams seen clearly (like the ones in the video) also powerful enough to burn your retinas out? And all that scatter seems that it would make it easy for such a thing to happen…

    • The fog produced by fog machines has a tendency to destroy electronics.

  • For the display…. you can simply hook up a video game shield to a small cheap tv and depending on the phone you have hack it a little to communicate with the sheild via IOIO or the Elecrtosheep, or if you have an iphone use the breakout you guys sell. then you can make a small remote with rf modules if u want and it can choose the song on the givin screen. Hope this helps :)

    • A video screen is too small and harder to mount to a wall. Well, none of this is going to be easy to mount, I spose. But also with the video, then it’s mostly down to code. That’s not as much fun to me. Feels less creatively satisfying.


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