pic microcontrollers for switching inputs

Discussion in 'The Projects Forum' started by cirep, Apr 19, 2015.

  1. cirep

    Thread Starter New Member

    Apr 17, 2015
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    Hi to you all,
    I have an old AKai receiver which i do not want to discard.Unfortunately the push to make switches that select the sources are out of order and this tends to be problematic when i want to change from one source to another.I was wondering if the controllers from the PIC family can be of help in that respect.A program that can handle five HIFI channels for a proposed IC would be most welcome.
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    If you need someone to design this for you (or even if you intend to do it yourself) you must first define exactly what it is you need i.e. inputs, outputs, logic levels, functions, available power-supply etc...
     
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    what switches do you have on the Akai system. Photos...
     
  4. cirep

    Thread Starter New Member

    Apr 17, 2015
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    I want to do it myself and the difficult part is the programming of the controller.The device i am planning to use is the 16c05 because i have got 3 of these new and unused.The logic levels must range from 0 to 3.3volts and must be able to cater for 4 inputs including phono.Idon't know though if the available bandwidth goes upto 16khz.A friend is helping me with this project and we first thought of using cmos ics to do the switching but space is tight in the receiver and a minimum of 5 ics are needed together with their associated components and this is not practical.I may be mistaken but i have never seen such a project be described in eletronics magazines
     
  5. cirep

    Thread Starter New Member

    Apr 17, 2015
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    I will post a photo soon because for the moment i am away from home.The switches are push to make and break as found on many old japanese hifi like sansui and pioneer.
     
  6. cirep

    Thread Starter New Member

    Apr 17, 2015
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    The power supply is 5volts.
     
  7. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Do you intend to use the Akai switches or are they the problem? How is a 16kHz bandwidth relevant?

    It might help if you draw a sketch showing how you intend to connect things together; it is not clear which bits of the Akai receiver you intend to keep and which bits you are replacing.

    You have a 5V supply available from the receiver?
     
  8. cirep

    Thread Starter New Member

    Apr 17, 2015
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    It would be a personal satisfaction to revive these old electronics with modern devices,.
     
  9. cirep

    Thread Starter New Member

    Apr 17, 2015
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    Only the switches are out of order on the unit and the rest of the equipment works perfectly well.To play a source i have to wrap a few wires together.Unfortunately i don't have a schematic to show you The model is a 5080.The 5volts can be obtained from a 15volts supply and with the help of a zener diode on the cassette circuit.The switches feed the sources to a preamplifier .Your help will be greatly appreciated to help us with this project but is it really feasible? I have never worked with controllers before but now i am very interested in them and want to try my hand on something new to me.
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Sounds like you describing a 'Radio Switch' mechanism?
    Max.
     
  11. cirep

    Thread Starter New Member

    Apr 17, 2015
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    B
    For the bandwidth ,i mean can the controller maintain same when it is switching sources?
     
  12. cirep

    Thread Starter New Member

    Apr 17, 2015
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    Its replacing a mechanical one by an electronic one.what could be the limitation of a controller doing that purpose?
     
  13. blocco a spirale

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    Jun 18, 2008
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    I'm not sure what you mean, are you thinking of running the audio through the PIC? You can't do this nor would you want to.

    If it were me, I would just use a 2-pole rotary switch to select the line-level inputs. The phono input would be a minor additional complication.

    If you intend to use a PIC, I suggest that you just pole the selector switches and when one is pressed, latch a corresponding relay on and release all others.

    If you don't wish to use relays, there are electronic switches available which are designed for audio that you could control from the PIC.
     
  14. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    if you cant get replacement switches,how about a rotary switch, why use a micro for something simple...
     
  15. cirep

    Thread Starter New Member

    Apr 17, 2015
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    I want to run the audio through the controller .I need your opinion on that.Am i looking too far?The idea is on paper is very simple ,upon pressing a switch corresponding to the source you want to listen to,the controller routes same to the preamplifier.
     
  16. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Asked and answered!
     
  17. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What about using solid state data Switches by Maxim?
    Max.
     
  18. cirep

    Thread Starter New Member

    Apr 17, 2015
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    Because mechanical switches introduce noise and because i wanted to try something i have never done before.To see such an "intelligent"device dictating operations inside an old receiver thrills me.
     
  19. cirep

    Thread Starter New Member

    Apr 17, 2015
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    Max Ics are not available where i am and i have to import them .Can you suggest some? I am open to all advice and in case the project with the controller cannot get along ,i may revert to any of the ideas you people have suggested.funny i know but the pic controllers keep haunting me as the little voice inside my head tells me with authority that i should stick with it.Am i rational?
     
  20. blocco a spirale

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    Jun 18, 2008
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    Good quality mechanical switches don't usually introduce significant noise unless the contacts are dirty or worn out, whereas, electronic switches will introduce some noise and distortion, it just won't get worse with age.

    Your requirement is very simple and you should have no problem writing the code yourself but you need to decide whether you use relays or solid-state switches. Either way, the code will be the same.

    I don't know what knowledge of PICs you have but I suggest that you first solve the problem by drawing a block diagram showing the inputs and outputs to your "black box" then create a flow chart and when you're happy that the logic works, transfer it to PIC assembly language.

    I don't think you'll need any more than 20 lines of code for this.
     
    Last edited: Apr 19, 2015
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