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FSLED Question

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The question is regarding backlighting my quadrant and the Glareshield etc.If I use led's to backlight switches and text, how many leds can I run off of the one position on FSled.If I can only run 1 led on each position, can I assign multiple positions on fsled to the one switch or (Nav lights).Or, is there a simpler way to do this if let's say it takes 20 odd leds to do the lighting. (There's probably 10+ just on the quadrant)Thanks for the help as alwaysDavid

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Don't run lighting leds through FSbus, it's a waste of resources. Use FSbus or whatever you're using for indications, warnings and anunciators. Run your backlight illumination LEDs separately, powered by an independent power supply, connected to your nav light double switch, it we're talking about a cessna, or connected to your backlight switches if we're talking about a jet.Greetings.

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Have a look at my site, there is a possible solution to your needs.

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Some people have used the christmas-light "light cable" successfully as well- easy to route behind the panel.Just as always, remember all this generates heat. Be careful with that.//Tuomas

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Claudio,Have read your article on Hacking the LED. Looks like this is an easy solution.If I understand correctly, by adding this mod to the FSLed board, and using a separate power supply, it replaces the need for FSDO.For clarity, 1. How many led's or lamps can be powered by each mod unit? 2. Can you produce this mod unit for each led position ie: 4x8 positions = 32 separate mod units (if you really wanted this many)My preference is to use LEDs for the backlighting due to low heat production and low voltage requirements.ThanksDavidPs: If I travel down this road, I'm sure I will have some more questions for you as I go. Hope you don't mind.

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>1. How many led's or lamps can be powered by each mod unit? It really depends on the transistors you are using: they account for the power you can drain from them.In secundis the PSU must have enough spare power for the number of lamps you are going to use.Remember that my scheme transforms the FSLED in pretty much a "switch".It just switches a number of transistors.How much power you are able to drain depends on the PSU you are using AFTER the transistors, and the transistors themselves.Notice this means that you can even use 24vdc,48vdc or whatever (theoretically even AC if you substitute transistors with TRIACs).You are using FSLED only to switch these transistors, what these transistors actually switch is of no importance to FSLED :)>2. Can you produce this mod unit for each led position ie: 4x8>positions = 32 separate mod units (if you really wanted this>many)Yes.It needs 1 transistor per FSLED led position, and 1 per row.This means that should you want to "transform" each of the 32 outputs you would need 32+4=36 transistors.>My preference is to use LEDs for the backlighting due to low>heat production and low voltage requirements.Yes, once Daken will have a 737 panel series, i'll use leds too.But for backlighting i would use a simple PWM unit that would allow me to regulate light intensity, instead of haveing full on and full off as with fsled.>Ps: If I travel down this road, I'm sure I will have some more>questions for you as I go. Hope you don't mind.No problem on this side :)

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Since you didn't ring, i assume youeighter gave it upor succeeded at first try!:)

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Hi Claudio,No, didn't give up (never) but have been away from a computer for the week-end.A couple of further questions.I have worked out that I need about 20 leds (green I think) for the throttle quadrant. The voltage of the LED's can vary between 1.2 and 3 volts. Can you tell me what power supply I would need and what transistors.Also, can you tell me a simple formula for working this out.Next question, if I continue this lighting process through to the other panels, will I need to make up this mod for each section with a seperate PSU for each mod or if the PSU is powerful enough, can I run it all off the one? As you can see, I have no idea how to work out power required.Next question, I went to my local Radio Shack (Dick Smith)here and spoke to one of the guys about your suggestion for adding a simple PWM Unit (which I understand to be a Power Modulation Unit) and the simple answer was to add a VR (variable resistor) (wound type, not carbon film) to where the resistor in the mod is now (replace it with the VR). Is this correct.ThanksDavid

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>I have worked out that I need about 20 leds (green I think)>for the throttle quadrant. The voltage of the LED's can vary>between 1.2 and 3 volts. Can you tell me what power supply I>would need and what transistors.Why they vary?As long as you use one type, the power requirements are the same.So why different voltages?My little suggestion on LEDs:buy them on ebay!They are much much cheaper then the usual channels.Personally i buy from "ubiditnow", free shipping and high power leds.Gve it a try.Anyway you can use one psu, and power different ramifications of leds with different resistors.>Also, can you tell me a simple formula for working this out.There isn't really a formula.Providing you can use one psu for everything (it is not always the case, but with leds is luckily), just add every power requirement (in the same unit: amps with amps, watt with watt).Then you will have the total power required, and can check that it is allowed by both the transistors you are using and the psu.For example using the BDX54/5ransistor couple, you can allow a maximum of 100v.Using compatible transistors you are limited, say for example you use BDX53/54, they are limited to 45v instead of 100v.That's all about it.These transistors can sustain almost whatever you throw at them :)>Next question, if I continue this lighting process through to>the other panels, will I need to make up this mod for each>section with a seperate PSU for each mod or if the PSU is>powerful enough, can I run it all off the one? As you can>see, I have no idea how to work out power required.Now with what i told you, you should be able.Let's continue with LEDs: each led has it's own power requirement, say for example 25mA.How many do you want to use?300?Ok that's 300 * 0.025 = 7.5A at the rated voltage of the LEDs (is indicated on the datasheet, usually something between 2v and 2.8v),this is the power you are going to drain from the PSU, so the psu must be able to feed it.As powerfull psus are costly you can very well divide your illumination into sections, linking them up in FSBUS by assigning multiple LED outputs to the same input.About powering up the leds:use parallel mounting.Two are the possibilities:one resistor for all the ledsone resistor for each led.The one common must be very big (calculate wattage by multiplying the drain amps for the power voltage, for example 12V * 7.5A = 90W), you can do parallel of paralles, for example dividing the total in 6 ramifications, each in parallel to the other, with 6 resistors that thus have to sustain only 15W.Another thing: to calculate necessary resistor for your particular led, select a current you want your led to work with (ammissible range is defined in the datasheet), and divide power voltage by current.For example, say you want to power your leds at 0.025A and 12V12v / 0.025a = 480ohm.>Next question, I went to my local Radio Shack (Dick Smith)here>and spoke to one of the guys about your suggestion for adding>a simple PWM Unit (which I understand to be a Power Modulation>Unit) and the simple answer was to add a VR (variable>resistor) (wound type, not carbon film) to where the resistor>in the mod is now (replace it with the VR). Is this correct.A VR (also known as POT for potentiometer) can't sustain that much current.If you take an old AT psu for example, it is well capable of delivering 12/15A on 12V channel, perfectly suitable for your 300 leds.Now with a POT you can't regulate 300 leds, with a PWM (Pulse Width Modulation) unit you can.Finally i suggest you start with a limited number of leds, maybe trying parallel mounting.Then when you become sure what you are doing, you can mount your thousands leds :)

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This is a new field of understanding electronics. I will learn as I go.It was my understanding that led's have the ability to 'light up' so to speak, between these two voltages.First of all, it is my intention to only light up the throttle quadrant first. I just wanted to try and understand how to expand this later on. You know when you are persuing this hobby, you tend to make the same thing a couple of times before you find the most efficient way.So, to simplify this for me, what do I need for 20 green leds (do they have to be high power led's?).Can you give me step by step instructions of power requirements ie: 12vdc 400mA etc.Transistors required.If possible, a basic diagram for a PWM unit (or a link to a schematic).Any other information I will need to make just this small 20 led version work.Thanks again for you information, time and patience.I see a lot of your responses in this forum, and they are alway helpful.RegardsDavid

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Another option is to use the "light cable" they sell for christmas decorations.. That might be quite easy to route around the panels.//tuomas

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>This is a new field of understanding electronics. I will>learn as I go.Ok, then this is gonna be a small electronics course :)>It was my understanding that led's have the ability to 'light>up' so to speak, between these two voltages.More precisely LEDs respond to current rather then to voltage.In fact you can power them even with 25Kv, as long as you use the appropriate resistor to KEEP the current down to a comfortable level for the led.The current value you can find on the datasheet.Say for example it is 25mA, following the fmaous formula V = R * I, if you have V and have I, you can find the necessary R.So for our example R = 25000 / 0.025 = 1Mohm.So you primarily drive the LEDs with current.The fact that current comes to depend from voltage is something that comes in handy when you want to modify the intensity of the light emission.Lowering the voltage, you lower the current too, and you end up with less light.We will cover this later speaking of PWM.>First of all, it is my intention to only light up the throttle>quadrant first. I just wanted to try and understand how to>expand this later on. You know when you are persuing this>hobby, you tend to make the same thing a couple of times>before you find the most efficient way.That's right.Then count the number of leds you want to use, sum up the current drain, and you'll see if your actual PSU can withstand it (i recommend using cheap AT power supplies).>So, to simplify this for me, what do I need for 20 green leds>(do they have to be high power led's?).Last question: no the do not HAVE to be high power, but my recommendation in a post above was to buy them on Ebay because you can find high power at a fraction of the cost of normal ones.My personal example: for 10$ i bought 50 blue leds rated at 6000mcd, with free shipping. Here at a not so expensive shop, i have to pay 1.16

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Thanks Claudio for your very detailed response.I think I have a grasp on it. I will attempt to put this all together and see what happens.You finished your response with a statement that leaves me with another question.'But i forgot to say that the PWM one can't be attached to the FSLED without an interface.'What interface do I need? I thought the PWM was attached to the leds.I'm sorry, but you may have to sketch up a little flow diagram for me if possible.I will check out the link sites you have given me and try to gain further understanding.ThanksDavid

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>You finished your response with a statement that leaves me>with another question.>>'But i forgot to say that the PWM one can't be attached to the>FSLED without an interface.'>>What interface do I need? I thought the PWM was attached to>the leds.It is a bit late now for a diagram, tomorrow i have lessons, but i will make one when i get home (about 1100Z).But i can elaborate a bit on my previous statement.A led can be seen exactly like a lamp: you give it power, and it lights up.PWM is a kind of technology, used by this or that device, do to a particular task (for example regulating light intensity, or motor speed or torque, etc).A PWM unit, uses the PWM technology to drive transistors that are capable to switch at the required speed (say for example the 120khz i cited on my previous post), and then these transistors do actually drive the device.But the controller of the PWM cycle cannot have its power chopped as it is doing with the device it is controlling.Since any FSLED line does almost the same thing as a PWM (if you want i can go into details, but the ground is that the output are cyclically switched, it's called multiplexing), if you connect a PWM unit to an FSLED line you would have a double frequency:1st is the PWM own chopping frequency2nd is the FSLED chopping frequencythus the whole resulting in something you didn't expect.I hope this is clear enough, now it's time to get some sleep :)

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Claudio,Thanks for all the info.Last week-end, I made the FSLED board, so armed with the information you have given me, this week-end I will attempt to make the mod and see what happens.I'll let you know.RegardsDavid

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Good luck :)Should you have any question, as always: feel free to ask :)If you use MSN and want to contact me, drop me an email and i will give you my contact.

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Claudio,A quick question. I have noticed on your mod for led, that you must run a common ground with the fsbus system (same PSU). I am running FSCom, FSAD, FSKey and FSLed. My PSU is a 12vdc 1amp pack. As I don't know the needs of the FSbus system, can you tell me if I have enough power to run the 20 leds with your mod and the FSBus system.Thanks again.DavidPS I have never used MSN, not by choice, just by lack of time.

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>A quick question. I have noticed on your mod for led, that>you must run a common ground with the fsbus system (same PSU).Actually it MAY work with totally two different PSUs.But i do not know if it could cause any damage to anything (the circuit, the psu, the device, etc...).So to stay on the safe side, i have put this constraint.> I am running FSCom, FSAD, FSKey and FSLed. My PSU is a 12vdc>1amp pack. As I don't know the needs of the FSbus system, can>you tell me if I have enough power to run the 20 leds with>your mod and the FSBus system.Should be enough but i do not know the exact number for each card.

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Um, am I just missing something, but why do you need to connect backlighting of your panel to FSBUS?I mean, you put a switch for panel lights, you connect your light cable or leds through the switch to a power supply.. why do you need to "tell" FS about it? If you want FS to know about it as well, so your on-screen panel lights up too, rather use a "two-pole" toggle switch which will give you two outputs - one for the lighting stuff, and another for FSBUS key card which you then route to FS panel lights, if you absolutely need to make FS aware of your physical panel lighting state..?//Tuomas

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Yeh, your right of course Toumas.I just like the concept of it all being run through FS.I think for simplicity sake, I might reconsider my plan.David

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Out of curiosity, can anyone answer the question of:What is the current draw for FSBus (1 FScom, 1 FSled, 1 FSkey, 1 FSad)I am running it with 12vdc 1amp.

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>Yeh, your right of course Toumas.>>I just like the concept of it all being run through FS.>>I think for simplicity sake, I might reconsider my plan.>>David>Yeah, but it is much better to separate the signal at the switch, there are "two-pole" toggles that have 4 or 6 contacts (6 if they are "ON-ON" type and 4 if they are "ON-OFF") - then it basically has two electronically separate switches that share the same toggle arm. Thus you just wire one of the pairs to FSBUS key module to get the signal into the sim, and the other pair to your electronics. It makes things a lot more simple.If you need it to be even more realistic, you can then wire the ground for the lamp circuit through another two-pole switch - the master battery one. That's how we do it on our cessna sim. Interior lights start to work after battery master is switched on.Of course it all can be done through fsbus as well via a relay, but I guess there are way more important things to do when building a simulator, dont waste your energy on this too much, would be my advice :)//Tuomas

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>What is the current draw for FSBus (1 FScom, 1 FSled, 1 FSkey,>1 FSad)If you have a multimeter, put it on the AMPS range (at least 1A, usually multimeters have 10A, or 200mA and below, so if this is the case, just use 10A) then put the + lead from the psu on the + lead of the multimeter, and the - lead of the multimeter on the + of the FSBUS system.You will read total power draw.I hope i have got the polarities correct: it doesn't matter if you have a digital multimeter, but may cause damages to analog multimeters.

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Claudio,I contacted Gary on one of the links the link you gave me for a PWM http://www3.telus.net/chemelec/Projects/PWM/PWM.htm and asked him if he would draw me a diagram to incorporate the PWM and the leds as one diagram.I have attached that diagram, my question is, how would I use your Led Mod to trigger this circuit, or is it not possible or not really worth it?ThanksDavid

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The scheme is correct, but not for interfacing with FSLED, it is just to use the circuit with a number of leds.I concur with Tuomas: it's nonsense to realize such a complicated interface to let FSLED power up or down *DIRECTLY* the leds.Just use a multiple poles switch, and there you go.

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