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  • O.T. - Micro-Controller Maker Movement

    A friend into Photography is using Arduino as a PhotoController.
    The Feb 2015 AudioXpress has an article "Arduino-Based Tube Power Controller Amplifier Controller"
    I've been following using Arduino as a Music Synthesis device...

    Who is using the various Micro-controller platforms and how?
    ( particularly, but not exclusively in Audio/Music )
    "Not a Speaker Designer - Not even on the Internet"
    “Pride is your greatest enemy, humility is your greatest friend.”
    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

  • #2
    Re: O.T. - Micro-Controller Maker Movement

    Originally posted by Sydney View Post
    A friend into Photography is using Arduino as a PhotoController.
    The Feb 2015 AudioXpress has an article "Arduino-Based Tube Power Controller Amplifier Controller"
    I've been following using Arduino as a Music Synthesis device...

    Who is using the various Micro-controller platforms and how?
    ( particularly, but not exclusively in Audio/Music )
    Not yet, but... I will likely assemble something to provide synchronized remote control of two NuForce MCP-18 multichannel preamps via their RS232 ports.

    Click image for larger version

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    "Our Nation’s interests are best served by fostering a peaceful global system comprised
    of interdependent networks of trade, finance, information, law, people and governance."
    - from the October 2007 U.S. Naval capstone doctrine
    A Cooperative Strategy for 21st Century Seapower
    (a lofty notion since removed in the March 2015 revision)

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    • #3
      Arduino-Based Tube Stereo Preamp Project

      http://circuitcellar.com/cc-blog/ard...reamp-project/
      "Not a Speaker Designer - Not even on the Internet"
      “Pride is your greatest enemy, humility is your greatest friend.”
      "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

      Comment


      • #4
        Re: Arduino-Based Tube Stereo Preamp Project

        I'm still on the fence about the Arduino boards. They make it easy for hobbyists to control advanced audio chips like volume controls and SPDIF interfaces and to do basic control of relays and other hardware. But I've always found it much more convenient to just use a tiny $3 micro on any amp board I make and dispense with all of the Arduino hardware "baggage" of connectors and wasted board space. Since a lot of the control functions end up poking into registers and doing things that are "chip-specific", the software is inherently hard to follow, and I don't see a whole lot of advantage to using C over assembly code programming for audio control applications. Also, a lot of the code for effective control of audio circuits needs to use interrupts and it needs to be very "lean" code. So up to now I haven't been interested in the Arduino software environment.

        But things are changing. The Arduino boards finally have a fairly strong support base, and it's not just the hobby/hacker crowd, as there are more and more sophistication applications for the Arduino, with a wider variety of add-on boards. With sites like Sparkfun, ITEAD Studio and HiFiduino, there are nice marketplaces for Arduino-based products. Also, there are more tools available to lower the entry cost for making your own shields.

        Another important development are the new boards with fast 32-bit processors that use the Arduino pinout (see the STM32 Nucleo). That extra horsepower allows running real DSP code in the micro instead of needing a host such as a PC to do the calculations. That's a game-changer. For example, it means that the user can select filter parameters from a simple LCD display, and the micro can do all of the number-crunching to calculate the coefficients for a DSP chip or else do digital preamp functions such as audio routing, mixing, volume control, simple filters, etc.

        In order to get my feet wet in the Arduino world, I designed a simple ADAU1701 board and sent it off to ITEAD Studio. I used an Arduino template for the PCB that was designed in Eagle, converted it to DesignSpark, and was able to put together the design very quickly--less than a week from start to finish. The cost for 5 boards at iTEADstudio was $19 plus shipping, which is amazing. I haven't received the boards yet, so I can't say too much about the process, but so far I've been impressed at the low entry cost and gentle learning curve of the Arduino board design.

        Maybe I'll actually do something with these boards, but there's a lot of software that I will need to pull together, and it may take a while.
        Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

        Comment


        • #5
          Re: Arduino-Based Tube Stereo Preamp Project

          I'm still on the fence about the Arduino boards.
          I'm not even near the fence; for the reasons you expressed:
          I'm also looking at other platforms ( Raspberry Pi etc ).
          Maybe I'll actually do something with these boards, but there's a lot of software that I will need to pull together, and it may take a while.
          I can appreciate that you have kept active in circuitry world; ( at least since those articles in AA. )
          While I studied Digital circuitry and had planned to go into Digital communications upon graduation in the 70's - Fate and my then employer led me into Software and Programming.
          So long story short - I've probably forgotten ( or ideally stored away ) more than I liked to have.
          Hopefully you will post your activity
          "Not a Speaker Designer - Not even on the Internet"
          “Pride is your greatest enemy, humility is your greatest friend.”
          "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

          Comment


          • #6
            Re: Arduino-Based Tube Stereo Preamp Project

            Originally posted by Sydney View Post
            I'm not even near the fence; for the reasons you expressed:
            I'm with you on this one. In the DIY "maker" world, Arduino's have their place, but I fear the day I find an Arduino in a finished commercial product...

            Comment


            • #7
              Re: Arduino-Based Tube Stereo Preamp Project

              Hold on, basic dumb question coming up based on what little i heard about Arduino and Pi.

              I assumed Aurduino's were used for controlling stuff and getting low level inputs from senors etc and executing simple commands and the Pi was more suited for heavy duty tasks like audio and video processing, etc as It is a full fledged computer with an OS, etc. micro-controller vs linux PC was my understanding.

              So, how do we use Arduinos for audio processing? I also didn't understand the Arduino and DSP processing - the DSP chip (ADAU1701) does the DSP processing similar to the minidsp - the Arduino replaces the PC for downloading the DSP curves to the DSP chip?

              Comment


              • #8
                Re: Arduino-Based Tube Stereo Preamp Project

                I saw something similar to this at Burning Amp. There, the designer used an Arduino board to receive IR, control input switching, and control some digipots (5-6 channels, IIRC). He also had another version that used relays to switch the volume setting. Sounded like a thumb piano while changing volume. If I was going to make a dozen or more of these, I'd consider moving to a PIC controller.

                But these are simple on/off applications.

                What would be cooler would be something that could be used to dynamically adjust bias current based on BJT die temperature for lowest crossover distortion in class AB amplifiers, or perhaps a sliding bias to keep an amp on the edge of Class A operation without having the amp dissipate several hundred watts while idling.

                I'm struggling a bit to come up with a speaker based application.
                - motional feedback for sub (done many times in analog domain; don't know about digital domain)
                - port control based on ??

                Comment


                • #9
                  Arduino + TDA7439DS + HEF4051 5.1 DIY remote controlled audio mixer w Output Mapping

                  http://electronprojects.blogspot.ie/...atmega328.html
                  "Not a Speaker Designer - Not even on the Internet"
                  “Pride is your greatest enemy, humility is your greatest friend.”
                  "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                  Comment


                  • #10
                    Re: Arduino-Based Tube Stereo Preamp Project

                    Originally posted by ani_101 View Post
                    Hold on, basic dumb question coming up based on what little i heard about Arduino and Pi.

                    I assumed Aurduino's were used for controlling stuff and getting low level inputs from senors etc and executing simple commands and the Pi was more suited for heavy duty tasks like audio and video processing...
                    That's true, but with the new 32-bit processors showing up on Arduino-compatible boards, it's possible to do some basic DSP operations. And with these newer chips, you can easily calculate the coefficients that a DSP processor like the ADAU1701 needs.

                    So, how do we use Arduinos for audio processing? I also didn't understand the Arduino and DSP processing - the DSP chip (ADAU1701) does the DSP processing similar to the minidsp - the Arduino replaces the PC for downloading the DSP curves to the DSP chip?
                    DSP boards like the miniDSP use a micro to control the ADAU1701. The micro loads the program into the ADAU1701 Program RAM and initializes the Parameter RAM. The micro also provides the connection to the PC to change the Parameter RAM in response to the miniDSP or other GUI. The Arduino can replace the micro on the miniDSP. In some ways that's a silly thing to do, since the Arduino board is a separate board and costs about 20 times as much as the micro that is already on the miniDSP board. But the reason you would do this is to allow real-time control of the ADAU1701 and make the miniDSP "more open". You could load your own programs and use the Arduino to read a keyboard or remote control and make changes to the ADAU1701 Parameter RAM based on those inputs. So for some "extreme hobbyists" the Arduino with an ADAU1701 shield is a dream come true. But as someone else pointed out, this is not a good design for a commercial product.

                    The PC is still needed to provide a nice user interface and to calculate the filter coefficients. The Arduino simply takes the pre-calculated data and puts it in the ADAU1701 Parameter RAM. But with a fast enough Arduino that can do 32-bit calculations and that has a Trig library, you could calculate the filter coefficients in the Arduino. And with a good enough display, you could pretty much dispense with the PC. There is a discussion on DIYAudio about using the new 32-bit controller boards to actually implement the filters, but it's a lot easier to let a specialized chip like the ADAU1701 do that work.
                    Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

                    Comment


                    • #11
                      Re: Arduino-Based Tube Stereo Preamp Project

                      Originally posted by neildavis View Post
                      ...But the reason you would do this is to allow real-time control of the ADAU1701 and make the miniDSP "more open". You could load your own programs and use the Arduino to read a keyboard or remote control and make changes ....
                      That is a large part of the allure.
                      A commercial product ( beyond Arduino capability ) that is along the lines of something I'd find useful:
                      http://www.ivie.com/index.php/iflex-1280
                      "The iFlex 1280 is an integrated digital signal signal mixer and processor with 12 mic/line inputs
                      and 8 line outputs. The internal signal flow, mixing components, and signal processing and routing
                      components are all custom configurable by the end user. The entire system design is user definable,"

                      This would integrate and eliminate gear in a live rig or a custom LMS matrix.
                      "Not a Speaker Designer - Not even on the Internet"
                      “Pride is your greatest enemy, humility is your greatest friend.”
                      "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

                      Comment


                      • #12
                        Re: Arduino-Based Tube Stereo Preamp Project

                        Originally posted by neildavis View Post
                        That's true, but with the new 32-bit processors showing up on Arduino-compatible boards, it's possible to do some basic DSP operations. And with these newer chips, you can easily calculate the coefficients that a DSP processor like the ADAU1701 needs.



                        DSP boards like the miniDSP use a micro to control the ADAU1701. The micro loads the program into the ADAU1701 Program RAM and initializes the Parameter RAM. The micro also provides the connection to the PC to change the Parameter RAM in response to the miniDSP or other GUI. The Arduino can replace the micro on the miniDSP. In some ways that's a silly thing to do, since the Arduino board is a separate board and costs about 20 times as much as the micro that is already on the miniDSP board. But the reason you would do this is to allow real-time control of the ADAU1701 and make the miniDSP "more open". You could load your own programs and use the Arduino to read a keyboard or remote control and make changes to the ADAU1701 Parameter RAM based on those inputs. So for some "extreme hobbyists" the Arduino with an ADAU1701 shield is a dream come true. But as someone else pointed out, this is not a good design for a commercial product.

                        The PC is still needed to provide a nice user interface and to calculate the filter coefficients. The Arduino simply takes the pre-calculated data and puts it in the ADAU1701 Parameter RAM. But with a fast enough Arduino that can do 32-bit calculations and that has a Trig library, you could calculate the filter coefficients in the Arduino. And with a good enough display, you could pretty much dispense with the PC. There is a discussion on DIYAudio about using the new 32-bit controller boards to actually implement the filters, but it's a lot easier to let a specialized chip like the ADAU1701 do that work.
                        Thanks... making a little more sense now...

                        Comment


                        • #13
                          Re: Arduino + TDA7439DS + HEF4051 5.1 DIY remote controlled audio mixer w Output Mapp

                          For anyone looking for a great deal on Arduino UNO/Mega2560....I have used these on quite a few audio projects and a couple of work related ones also.Free shipping.

                          http://www.sainsmart.com/arduino/con...no-uno-r3.html
                          http://www.sainsmart.com/arduino/con...ga2560-r3.html
                          NLA

                          Comment


                          • #14
                            Re: Arduino-Based Tube Stereo Preamp Project

                            Originally posted by neildavis View Post
                            I've always found it much more convenient to just use a tiny $3 micro on any amp board I make and dispense with all of the Arduino hardware "baggage" of connectors and wasted board space.
                            I think the problem is that you're far too competent to be getting most of the benefit. :P

                            Here's an example use of an Arduino:
                            Step 1: Design 6 channel PGA2311 attenuator PCB with socket for 16-pin Arduino derivative. (You can get them crammed down to the size of a standard DIP IC.)
                            Step 2: Purchase encoder, LCD, and other devices with convenient predefined software library - for a few bucks each.
                            Step 3: Borrow lots and lots of someone else's code.

                            For someone who hasn't got an electrical engineering degree, the standardization alone is amazing.

                            EDIT:
                            I'm a big fan of the Arduino generics. While dropping $30 on a large board is a bit silly, spending $6 to add USB programming and a serial terminal to a convenient and removable microcontroller module is definitely worth it.

                            Comment


                            • #15
                              Re: Arduino-Based Tube Stereo Preamp Project

                              Originally posted by spasticteapot View Post
                              I think the problem is that you're far too competent to be getting most of the benefit. :P
                              Nah, just too old :(

                              I had quite a few micro-based projects way before the Arduino was available, and I would have used it if I could. I made a tailgate latch release for the kids on our 1987 Taurus wagon. The micro "listened" to the rear-window defroster voltage, and when it saw the right on-off sequence, the micro activated a PWM servo motor, which released the latch. And then I used another servo motor and arm as a "spinner" for a home-made Candyland game. The player pieces had magnets on the bottom, and when they passed over reed switches under the board they would get bonuses and a light show.

                              The strangest applications have been "art projects". I made a large wall-mounted infinity mirror that played Asteroids. And another was art project that my wife needed--it was an infinity box with mirrors on 6 sides of a 1-foot cube. We had a small peephole etched in one of the mirrors for people to view the crazy stuff she had put in the box. The micro controlled a black light and other colored lights. That infinity box was one of the most difficult debugging challenges I had. The box would work fine for about an hour and then stop, and I couldn't figure out why--it took me over week before I figured it out. That was back in the days of micros with UV-erasable memories, and it just didn't dawn on me that whenever the black light got turned on, it would start erasing the memory.

                              And so on... I've actually made a lot of projects where an Arduino would have done a great job and made things a lot easier.

                              For someone who hasn't got an electrical engineering degree, the standardization alone is amazing.
                              True--the prices have dropped and there is a lot more code to appropriate. But something that would really help is a nice aluminum case with a cutout that could easily fit an Arduino LCD display. I've made a number of the 8-channel PGA4311 preamps. But I've had to use my own CPU/Display because there is no Arduino solution that I know of that will fit in a case like the one in the picture. I just buy the preamp kit and throw away their micro and make my own board. I think a nice Arduino Display/Case combo would result in a lot more audio applications.

                              Free Passive Speaker Designer Lite (PSD-Lite) -- http://www.audiodevelopers.com/Softw...Lite/setup.exe

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