Lowest value resistors for Full LED?

Shop Forums QnA Lowest value resistors for Full LED?

This topic contains 6 replies, has 2 voices, and was last updated by  ALau 1 month, 1 week ago.

Viewing 7 posts - 1 through 7 (of 7 total)
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  • #5488

    ALau
    Participant

    Hello,

    I bought and just finished building a B.87 EX X2. Great piece of kit and now I am not afraid of working with SMD components! Everything is working (more or less… Cherry MXs are not consistent with the clicks), even the RGB LEDs are all working. However, the LEDs on each key are way too dim. I purchased “purple” LEDs from Ebay, and you had recommended 820 ohms, which works. I would like to lower the resistance to increase the voltage and current for each LED.

    I know 330 ohm is too low from your FAQ. What is the lowest resistor rating you can recommend?

    #5489

    Hi

    We recommend 820 ohm resistors as the lowest one,
    since our PCB supports both in-switch LED and RGB LED.
    USB has a currency limit.
    If you set in-switch LED too bright, it doesn’t anything but would-be malfunction.

    Probably you can set the brightness by using bootmapperclient.(http://blog.winkeyless.kr/183)

    Thanks.
    Hojin.Yi

    #5490

    ALau
    Participant

    Thanks for your quick reply. I have set the Full LEDs to maximum and the RGB LEDs to be at 11 (minimum) using the bootmapperclient before asking. =(

    Since RGB LED at 11 is good level for me, I was hoping to make the in-switch LEDs use more current.

    #5492

    Hi

    Could you try to turn off all RGB LEDs and then test it?

    If the brightness is still dim, you should check in-switch LEDs.
    (Could you tell me the model?)

    Thanks.
    Hojin.Yi

    #5495

    ALau
    Participant

    I did some checking with my multimeter. The RGB LEDs are using 62 mA at all brightness levels (1 to 255 on bootmapperclient). When RGB LEDs are at level 1, in-switch uses 5 mA. When RGB LEDs are at 255, in-switch uses 1 mA.

    Even with RGB LEDs set to off, in-switch LED use 5.1 mA.

    Here is the link to the purple LEDs I am using (http://www.ebay.com/itm/100pcs-1-8mm-Transparent-Water-Clear-Purple-UV-Light-LED-Diodes-Ultra-Violet-USA-/121741964679?hash=item1c5862f587). (3.0V forward, 200 mcd)

    Is there a way to add a resistor in series with the RGB LEDs to reduce current usage? Then I can use a lower resistor for the in-switch?

    #5502

    I think the value of currency is correct.

    Around 5mA is maximum for a in-switch LED.

    You should check your in-switch LED how bright it makes when it has 5 mA currency.

    Thanks.
    Hojin.Yi

    #5506

    ALau
    Participant

    Thanks for all of your help and time on this!

    I have decided to switch to pink or blue in-switch since I realized that I was making UV-A light along with the purple. UV-A is probably not good for the keyboard and me.

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