COMPLETE Project Whisper, Arduino version

Discussion in 'Guides, Mods, and Upgrades' started by Rob Heinzonly, Apr 18, 2016.

  1. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    A couple of weeks ago @JvdP started a project to reduce the sound coming from the numerous fans on the BigBox. By coincidence, I was working on a similar project, however with a different approach: the Arduino.

    Currently I have an Arduino Uno sitting in the 'Basement' of my BigBox, doing stuff with the WS2812b ringleds mounted earlier under the heated bed. Time to let the Uno do some other things: driving the back case-fan of the BigBox by means of PWM and a PID regulator.

    1. The components.

    The following components are needed:
    Total costs: $ 10.42

    2. The simplified schema:

    [​IMG]

    • DS18B20 temperature sensors are nice little things. They need no adjustments and they communicate over one single wire. Every sensor has it's own unique address.
    • The LCD screen is communicating via the I2C bus with the Arduino Uno. This makes the setup easier and saves you from connecting seven separate wires to the Arduino.
    • The casefan is driven by a PWM signal coming from the Arduino. The fan is running on 24V so a NPN transistor is needed in order to give the fan the right voltage. The schema for that circuit looks like this:
    [​IMG]
    A 5V signal coming from a PWM pin on the Arduino is switching the NPN transistor. The case-fan motor above the transistor needs an extra diode to prevent damage to the transistor, and an extra capacitor.

    3. Theory of operation

    When the BigBox is turned on the case-fan is turned on for 1 second at 100%, after that is it tuned down to 2% of capacity.
    The Arduino is measuring the difference in temperature between the Rumba fan (T-in) and the case-fan (T-out). If the difference is > 7°C then the case-fan is switched on. This value is fed into a PID regulator. The output signal is a PWM signal and is given to the NPN transistor, who will then drives the case-fan. The PID script very simple and looks like this:

    [​IMG]

    4. Is it working ?

    Yes ! And the strange thing is, it is working better than I expected. at 95% of the time, the case-fan is running at 2%, even after 2 hours of printing.

    UPDATE: when printing at higher temperatures, the fan is pushed to 100%. Today I was printing Corlorfabb_HT at 265°C and the heated bed on 115°C, the case fan is constantly running at 100%

    5. LCD case

    For the LCD screen I made a nice case in Solidworks:

    [​IMG]

    And mounted it on the BigBox:

    [​IMG]

    [​IMG]

    [​IMG]

    The two red buttons are for the leds (more about that later). Now dinner is calling ;)
     
    #1 Rob Heinzonly, Apr 18, 2016
    Last edited: Apr 19, 2016
  2. daveyweaver

    daveyweaver Member

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    Looks very good. Thank you for sharing.
     
  3. R Design

    R Design Well-Known Member

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    Nice job indeed.

    A good budget and accessible components.

    As a matter of interest, what's the highest that you've seen the fan go up to?
     
  4. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    10% or so, but summer hasn't started yet ;)
     
  5. Kick2box

    Kick2box Well-Known Member

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    It's nice. Did you think about using a micro or nano instead of an uno and put it into the top case?
     
  6. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    @Kick2box : Yes I did think about that. But I found in more convenient to use a PCB on the Arduino Nano and mount all the parts on it (connectors, transistors and the lot)
     
  7. gearmesh

    gearmesh Well-Known Member

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    Nice work. Are you going to share the printable case file?
     
  8. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    gearmesh likes this.
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    Do like the case design :)
     
  10. Stefan

    Stefan Well-Known Member

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    Is it just me or are the images broken (404 file not found)
     
  11. gearmesh

    gearmesh Well-Known Member

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    Thanks!
    I dont have my Bigbox yet but i have everything to start this except the ability to print the case.
    Thanks for the file. I just ordered the misc parts and I will build as they arrive.
     
  12. gearmesh

    gearmesh Well-Known Member

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    Do you know where your LED/buttons came from? I figure when I make one I will need the same size to fill those holes :)
     
  13. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    I got them from ebay (link)
     
  14. Kiwimaddog

    Kiwimaddog Member

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    Hi. Regarding this Project whisper.
    Has anything been done with regards to setting the steps for the drivers on the Ramps-card? for example, setting the X / Y to 1/16 - 1/32 step(Jumpers 001 - 101) to make the motors more quiet? I have not tried it myself but am looking for examples if anyone else has, Since i understand this might reduce the noice-level when printing and the X / Y probably won't need the torque of 1/8 that I believe is default on the Ramp(at least for me with the hybrid, lighter carriage).
     

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