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R2 Lighting during printing

Discussion in 'Mods and Upgrades' started by tkoco, Apr 4, 2020.

  1. tkoco

    tkoco - -.- --- -.-. ---
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    This thread is a place holder for a project of mine to address the lighting of the print job in progress. I've already done the "Proof Of Concept" work on this issue and the mod works quite well.

    (ref: http://community.robo3d.com/index.php?threads/light.19043/ )

    Unlike the implementation chosen for the above link, my implementation is simple and only requires a 5.5 mm White LED, one resister and some wire to connect everything.

    I'll update this thread once I have finalized the parts list and procedure. Updated!
     

    Attached Files:

    #1 tkoco, Apr 4, 2020
    Last edited: Apr 11, 2020
    mark tomlinson likes this.
  2. tkoco

    tkoco - -.- --- -.-. ---
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    Parts needed for this mod:

    1 white LED 5.5 mm diameter
    510 Ohm 1/2 watt resistor ( read Preamble for more information )
    Wire to extend the lighting power
    Heat shrink tubing ( to cover the bare wiring )
    Electrical tape

    Tools:
    Soldering iron 20 watt & small diameter solder.
    Sand paper 200-220 grit
    Hand tools, like #2 Philips screwdriver, etc.

    While doing this mod, be careful to monitor the positive and negative wiring as you connect things. Nothing will ruin your day faster than to wire the new LED in backwards and fry something.
     
    #2 tkoco, Apr 11, 2020
    Last edited: Apr 11, 2020
  3. tkoco

    tkoco - -.- --- -.-. ---
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    Preamble:

    We are going to tap into the 12 volt power which lights the 2 LED modules in the R2 printer. A typical white LED will drop around 3 - 3.3 Volts depending on the manufacturer. We will need to drop the around 9 volt difference. Also, a white LED can need 15 to 20 ma of current to get a decent amount of luminescence. We will use 18 ma as the target current and 9 volts as the voltage to drop. 9 / .018 = 500 Ohm of resistance and the wattage of this resistor - .018 * .018 * 500 = 0.162 watts. To allow for derating of the resistor, we will need at least twice the calculated wattage or 0.324 watts. The next larger typical wattage ratings will be 1/2 watt

    So 510 Ohms at 1/2 watt, or 2 each 1/4 watt 1000 Ohm resistors in parallel, or 4 each 1/8 watt 2200 Ohm resistors in parallel will get the job done.

    Next, the domed LED will project too narrow of a light beam to be usable to broadly illuminate the print bed. So, the dome part will need to be sanded down to 1) broaden the emitted light beam & 2) to help diffuse the emitted light.

    So given this information, construct the LED assembly as shown below.

    LED.jpg
     
    #3 tkoco, Apr 11, 2020
    Last edited: Apr 11, 2020
  4. tkoco

    tkoco - -.- --- -.-. ---
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    Remove the front cover of the R2 printer. Instruction are found in this thread http://community.robo3d.com/index.php?threads/replacing-r2-touchscreen.19684/

    On the left side of the front framework, carefully pop out the LED module. You will need to scrape away the rubber coating on the free end of the module. Tin the two pads and solder on the extra power wiring. Carefully mark which wire is positive and which one is negative. Cover the connection with heat shrink tubing and shrink the tubing for mechanical strength. Then remount the LED module.

    Additional power cabling.jpg
     
  5. tkoco

    tkoco - -.- --- -.-. ---
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    Wrap the LED wiring with electrical tape. With the LED module seated into the frame, carefully route the new wiring up behind the top hinge. Loosen the crew so that you can move the frame for routing.

    LED_behind_hinge.jpg
     
  6. tkoco

    tkoco - -.- --- -.-. ---
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    Insert the LED assembly into the hole in the framework.

    Seat_LED_into_Hole.jpg
     
  7. tkoco

    tkoco - -.- --- -.-. ---
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    Reassemble the R2 and tighten the screws. Don't forget to plugin the loose cables into the Raspberry Pi which hopefully you had disconnected prior to popping out the front cover.

    Once everything is together, power up the R2 printer. Tap the Motor Control and then Home button. Watch the new LED light up.

    Probably would be a good idea to re-level the print bed ( in case you bumped it while working on your R2 printer )
     
    #7 tkoco, Apr 11, 2020
    Last edited: Apr 11, 2020

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