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Mike Kelly's Printer

Discussion in 'Show and Tell' started by Mike Kelly, Jan 27, 2014.

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  1. Ziggy

    Ziggy Moderator
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    Mike

    Servo(s) have 3 leads (Sig, +5v, Gnd) and plug directly into the AUX1 connector on the Ramps

    http://reprap.org/mediawiki/images/c/ca/Arduinomega1-4connectors.png

    Marlin has all the servo control firmware built in, including options to power up/down the servo. Test using gcode M280.

    Important configuration.h data is

    #define NUM_SERVOS 1 // Servo index starts with 0 for M280 command


    #define SERVO_ENDSTOPS {-1, -1, 0} // Servo index for X, Y, Z. Disable with -1
    #define SERVO_ENDSTOP_ANGLES {0,0, 0,0, ??,??} // X,Y,Z Axis Extend and Retract angles

    where ?? is in the range 0-90 degrees
     
    #101 Ziggy, Nov 23, 2014
  2. Mike Kelly

    Mike Kelly Volunteer

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    Ziggy my current configuration I'm using the RRD fan extender on the servo ports. The solenoid switch I'm using is a 5v on/off voltage. I'm hoping to use a pin like D1 to control the solenoid but I'm not sure that's possible?
     
    #102 Mike Kelly, Nov 23, 2014
  3. Ziggy

    Ziggy Moderator
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    Suggest moving the RRD extender so at least one servo set of pins is available out of the 4 sets.

    If you are using a solenoid (not a servo) to extend the Z probe, then another option is the Z probe "sled" idea. ie Use the sled activate/docking output to control the solenoid. But you will need a FET switch to handle the solenoid current and some diode reverse polarity protection when the solenoid is turned off.

    https://github.com/ErikZalm/Marlin/issues/1014

    Of course as an alternative you can always mod the firmware code to switch on/off any free digital output on Ramps AUX 1 or 2 connectors
     
    #103 Ziggy, Nov 23, 2014
  4. Mike Kelly

    Mike Kelly Volunteer

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    Well then I need a way to control my parts fan. It might be possible to solder directly to the pins from the RRD fan extender. I assume they sell pins that are double length for making circuit build sandwiches. The RRD uses D6 and D11 so D4 and D5 should still be available.

    What does the FET switch require? I have a spare STP55NF06L, like what drives the heaters. Do I just mimic their circuit of a 10 ohm resistor between the output and the FET with a 100k resistor to ground for a filter. Then I'm not entirely sure what you mean on the reverse polarity protection. Do I need a diode on the solenoid power line or on the digital pin side?

    I'm gonna look at Thantik's firmware here and see what he did to enable the solenoid.
     
    #104 Mike Kelly, Nov 23, 2014
  5. Ziggy

    Ziggy Moderator
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    Simple FET circuit to control a solenoid is like this

    upload_2014-11-24_9-55-25.png

    The diode (IN4001 or similar type) is there to kill the reverse polarity voltage spike when the solenoid is switched off.
     

    Attached Files:

    #105 Ziggy, Nov 23, 2014
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  6. Mike Kelly

    Mike Kelly Volunteer

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    Thanks man. I figured out that with M42 command I can toggle a pin. I think I'm going to just tell it to enable the probe that way using a digital pin then not worry about messing with the servo port.
     
    #106 Mike Kelly, Nov 23, 2014
  7. Ziggy

    Ziggy Moderator
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    Actually the 5v supply from the Arduino board will struggle to provide enough power to the solenoid. Would be better to use 12v supply if you can. Just change the VDD value in the diagram above.
     
    #107 Ziggy, Nov 23, 2014
  8. Mike Kelly

    Mike Kelly Volunteer

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    I agree that the arduino can't. Though 12v would provide more strength than I'd like. The 5v from the Ramps triggers it fine though the arduino doesn't. I'm gonna make a mosfet switch to use the ramps power instead of the arduino or I can use a 5v supply
     
    #108 Mike Kelly, Nov 23, 2014
  9. Ziggy

    Ziggy Moderator
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    The ramps 5v comes from the Arduino board 5v regulator. So every milliamp of 5v power puts more strain (and heat load) on that Arduino 5v regulator.

    If you prefer 5v for the solenoid, I suggest you use another 5v regulator (like a LM7805 three terminal regulator) with 12v as the source.

    The LM7805's are really simple to use and very cheap on ebay - see diagram 9 (fixed output regulator) in this spec sheet.

    https://www.fairchildsemi.com/datasheets/LM/LM7805.pdf

    You don't really need the capacitors. Just the regulator is fine for most applications.
     
    #109 Ziggy, Nov 23, 2014
  10. Mike Kelly

    Mike Kelly Volunteer

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    I thought the ramps would down convert 12v to 5v for the arduino? Electronics is my weakest point
     
    #110 Mike Kelly, Nov 23, 2014
  11. Ziggy

    Ziggy Moderator
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    Unfortunately the only 5V regulator is on the Arduino Mega board. When LCD displays etc are added this regulator is really working hard.

    Another option to provide a separate source of 5v (at up to 2 Amps) is to use one of these

    http://www.ebay.com.au/itm/DC-DC-LM...Electrical_Test_Equipment&hash=item5d45619bfb

    There are 100's of these on ebay. They are easy to connect (solder in) and the volts output is adjustable.
     
    #111 Ziggy, Nov 23, 2014
    Last edited by a moderator: Nov 24, 2014
    3 people like this.
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    #112 mark tomlinson, Nov 24, 2014
  13. Mike Kelly

    Mike Kelly Volunteer

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    Thanks for the help guys. I'll pick up a few step down converters.

    You should see my printer right now. Getting hard to recognize....
     
    #113 Mike Kelly, Nov 24, 2014
  14. Galaxius

    Galaxius Well-Known Member

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    #114 Galaxius, Nov 24, 2014
  15. Mike Kelly

    Mike Kelly Volunteer

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    Not much to look at right now...

    [​IMG]

    Only 2 original plastic parts remain. Thinking of getting an aluminum build plate and redoing the Z idlers...
     
    #115 Mike Kelly, Nov 24, 2014
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  16. SteveC

    SteveC Well-Known Member

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    Mike, Any idea if the cable guide chain will add much noise? I printed a few of them out and started worrying about the noise.
     
    #116 SteveC, Nov 24, 2014
  17. Mike Kelly

    Mike Kelly Volunteer

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    @donhuevo would be the better person to ask. I don't tend to hear them running but my 24v power supply has a ridiculously loud fan so that drowns out all noise
     
    #117 Mike Kelly, Nov 25, 2014
  18. donhuevo

    donhuevo Active Member

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    At least for my purposes under the bed, the noise isn't an issue at all. Moving the bed by hand with the printer powered down, I hear the motor and not the conduit.
     
    #118 donhuevo, Nov 26, 2014
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  19. Mike Kelly

    Mike Kelly Volunteer

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    The shape of things to come...

    [​IMG]
     
    #119 Mike Kelly, Nov 30, 2014
  20. Brandon Quimson

    Brandon Quimson New Member

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    can i use it with my current carriage?
     
    #120 Brandon Quimson, Nov 30, 2014
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