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LED light Question

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  • LED light Question

    I was breaking down my 90mm F-18 to use for spare parts for my future HP version I plan on getting here in a couple months and I took out the LEDs. My question is, I want to use the green NAV LED for the HUD display in my HSD F-16. Can I simply plug the black and red lead into one of the free AUX ports of my Spektrum AR9350 9-Channel AS3X Sport Receiver? I'm not well-versed in voltage limitations for basic LED lights. Appreciate any help!
    My YouTube RC videos:
    https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

  • #2
    I posted this link in the Tank forum as they use various LED's. Basically, if you have enough voltage, but don't exceed the rated voltage by too much you should be good.
    The questions are: What is the forward voltage of the LED you're planning on using and what is the supply voltage from the receiver?

    https://www.ledsupply.com/blog/what-...ow-about-leds/

    https://www.ledsupply.com/blog/how-does-a-5mm-led-work/

    You may want to be on the safe side since MotionRC doesn't publish any of the specifications for their LED's by using an LED light controller and hope it works for the LED's you plan to use. You plug the controller into your receiver.

    https://www.motionrc.com/collections...-controller-v3

    Or, you could probably buy a green 5-6volt LED for 50 cents and plug it directly into your receiver.

    Comment


    • #3
      Originally posted by Aros View Post
      I was breaking down my 90mm F-18 to use for spare parts for my future HP version I plan on getting here in a couple months and I took out the LEDs. My question is, I want to use the green NAV LED for the HUD display in my HSD F-16. Can I simply plug the black and red lead into one of the free AUX ports of my Spektrum AR9350 9-Channel AS3X Sport Receiver? I'm not well-versed in voltage limitations for basic LED lights. Appreciate any help!
      Aros, Those two LEDs are basic 3v, but can be run at a higher voltage (5v) to increase brightness, but shortens the life span. Alpha wrote a post a ways back that explained it to me when I was blowing up NAV lights on my Spittie by plugging those directly into an RX battery stating pretty much what Beeg wrote. If you plug your blue box into a RX and battery you could measure the output voltages for each of the light ports. If you do not have a way to do that, let me know and I'll do it and chronicle it here for everyone. Best, LB
      Captain: Got any ideas?
      F/O: Actually not.
      — Captain Chesley B 'Sully' Sullenberger III and F/O Jeff Skiles—

      Comment


      • #4
        Thanks Beeg and Elbee , very helpful! I think I am just going to go for Option #3 and buy a 5V green LED and plug in direct. Now it's trying to find a single 5V green LED with a long black/red extension and standard connector (800-1000mm). LB, as far as if you are feeling adventurous and for the sake of public domain info if you wouldn't mind to chronicle away? Thanks!
        My YouTube RC videos:
        https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

        Comment


        • #5
          These are pre-wired 3mm.
          https://www.amazon.com/Lighthouse-LE.../dp/B00TA4F7FA

          Unless you want surface mount LED's.

          Soldering irons are your friend! Instead of buying a pre-wired LED, just take an old servo extension, pull off the signal wire, solder the positive and negative to the correct LED polarity with a little heat shrink or tape you're good to go!

          Comment


          • #6
            I was looking at those very ones earlier...Do they not come with the connector or do you have to solder them on to the wires? Soldering is one of those skills I should have mastered eons ago in this hobby but never did. Go figure, lol.
            My YouTube RC videos:
            https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

            Comment


            • #7
              Don't think they come with connectors. I can make one up for you if you need it. If you get pre-wired LED's the neatest arrangement would be to crimp terminals for the connector. Would be easier to just take a servo extension and solder it to the LED. Or, I can get my brother to do it since he's up your way.
              Better yet, invest in a basic soldering pencil, get some regular rosin core solder, a little heatshrink and there are enough folks on this forum experienced at soldering to get you going and soldering in no time. This particular solder job is one of the easiest so success is pretty much assured with proper prep and equipment.

              You've heard the saying "Give a man a fish he eats for a day. Teach him to fish and he eats for life."

              Comment


              • #8
                I know, I know...It's been one of the more embarrassing admits for me since I have been in this hobby for over two decades now. I used to have a flying buddy that didn't mind doing all my soldering for me and I got spoiled (and complacent). This is the kick in the rear I need to just go ahead and invest in a solder setup and learn already. Thanks for the kick!
                My YouTube RC videos:
                https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

                Comment


                • #9
                  This thread is a couple months old but I just happened upon it. Let me add some general info and some detail:

                  GENERAL:
                  A key point is that LED's are unusual, in that you can't assume things like "3V was OK, so 4V should also be OK." It doesn't work that way. A small increase in voltage could give you a small increase in current, or it could give you a large increase in current and burn out your LED immediately. It is also important to know if you have a naked LED or an LED with a resistor built in. You can find both in the marketplace. If the resistor is not built in, you MUST add one.

                  DETAIL:
                  The D in LED is diode, which means that the "naked" LED (without an embedded resistor) is very much like a diode. That means it contributes an almost fixed voltage drop, and has almost no resistance after that point. Raising voltage across the bare LED beyond that point will VERY quickly burn it up. The simple ideal equation for a bare LED is based on two characteristics: the max current it can take (let's call that I_led), and the voltage drop across it (let's call that V_led). Then if your input voltage driving the light is V_in volts, then you need to add a resistor that is such that R x I_led = V_in - V_led. Normally you don't want V_in to be too much more than V_led, otherwise most of the power is going into the resistor, not the LED. Implicit in this model is that the voltage drop across the diode is always constant and does not increase with current. Obviously that is an ideal model, but close enough....if you are counting on a bare LED to have non-zero resistance you are playing with fire.

                  So for example, suppose V_led was 2.5v, and V_in was 3V. You might be tempted to think "well, 4V should be OK, that is only 4/3 higher". But you would be wrong. With V_in = 3V, there was only 0.5v going into the resistor. So by going from 3v to 4v you aren't increasing the current by a ratio of 4:3, you are increasing it by a factor of 3:1 (since there is now 0.5v x 3 of headroom between V_led and the supply of 4V). Most likely you will experience a pop and smoke in this scenario.

                  Comment


                  • #10
                    The pop and smoke I experienced was my head exploding trying to follow your informative explanation.

                    Man, you really can learn something new every day. Thanks for taking the time to explain that!
                    My YouTube RC videos:
                    https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

                    Comment

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