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Gear LED cirquit (electronic specialists .. little help...

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Quick explanation.I study for Designer (idnustrial product) and our first assignment in dedicated fysics is to do something with LED's. The assignments we could chose from were waaaaay to easy I believe so I chose to invent my own (as was allowed).To combine both education with my sim I chose to try to create something usefull for the sim.The idea is to build a cirquit on 12V (PC power sup) which will light 4 LEDs as in the Fokker50 cockpit. 1 is blue and is mounted into the gear lever. 3 are green and are .. well y'all know these green ones.I have no experiance designing any cirquitry so if what I came up with so fare is anything good, I'll be amazed :)The idea is to use a push button as well as a relais (so that I have both a button and a switch). Then there are 3 timers (NE555 IC's), a set of OR ports (CD4071) and a set of NAND ports (CD4011) used as NOT ports.I made this cirquit based on what I read from datasheets and a few examples found on the web.If anyone can help me out here, that would be super :)2 things I need:1) is this cirquit correct ? what needs to be changed ?2) how the hell do I calculate the R's and the C's ?http://users.skynet.be/plipke/Schema2.GIF

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To give just a little more info:The system should work such that when the relais is opened the green leds are on. (meaning the plane is with gear down). When the button is pressed the timers start; turning on the blue led. Also the relais is closed turning off the green LEDs instantly.After the timer stops the blue led is turned off. (the gear is up).Now we push the button again. The timer starts again; turning on the blue led. The relais is opened again. This time only the timers keep the signal at the exit of the OR high and thus the green leds dark. Once the timers stop (at different times) the both inputs to the OR are low, thus turning on the green leds.The idea is to get 6, 7 and 8 seconds time delay by the timers. With the 8 seconds for the blue led and 1 of the green ones.

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If you use fsbus,why don't make it in CCC?I don't know how yet, but I think it's possible.Jan.

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I think the thing above can't do what you want.As far as i know the 555 can work as an oscillator, pulse generator, pwm generator, and that kind.But not as a counter.You need a counter for your thing to work.Example:you have an oscillator generating 5 pulses per second, then 3 counters.Each of these counters are configured to count a number of pulses before putting their output to high.First problem is this.Second is the transistor and the reset of the counters:the button is momentary i assume (not maintaining the position).If so, you need something that with each pulse of your button changes and maintains its state (don't remember its name :().In my opinion you need two of these.Gonna make a block schematic for you, wait :)

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>If so, you need something that with each pulse of your button>changes and maintains its state (don't remember its name :().It's called FLIP-FLOPAt a pulse on the input, it changes state of the output between logic HIGH and logic LOW.Here is my scheme:http://forums.avsim.net/user_files/94358.gifExplanation:the oscillator is always active, generating that many pulses per second.The counters cannot count as long as the reset input is high.The button makes the FLIP-FLOP change state.The state of the FLIP-FLOP drives both the counters' reset input and the blue led (no need for a relais-rel

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When exactly should the blue led light up?Both on lowering and on rising the gear?Or only one of the two?Which one?

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Folks folks ... read some 'bout the 555 first then :(Inside the 555 there is a flipflop and the 555 can both be used astable (oscillator / timer) or monostable (delayer / single puls generator)And using FSbus ... first I have no FSbus, second that would be easy again and not sutable for my school project.

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Both.During any gear-travel .. the blue led is on inside the rounded transparent knob on the gear lever.The green leds only go on when gear is detected fully down.

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I need a more torough datasheet for the 555, the one i have is not very complete :(Do you have one?

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I have 2.One from Philips and one from another brand.Lets see:www.datasheetcatalog.comThere if you type to search for "NE555", you'll find some.I noticed 1 more issue in my cirquit. I use a relais but that's not the correct component.What I need is this:push button: 00100000000000000000000000000010000000000000000000000component..: 00111111111111111111111111111100000000000000000000000So that it seems as though there is both a push button in my system as well as a switch.

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>push button:>00100000000000000000000000000010000000000000000000000>component..:>00111111111111111111111111111100000000000000000000000I think this is exactly a flipflop?I found the monostable operation, with which you pretty much solve the blue led problem.But there is no mention of counting abilities :(Monostable, astable, frequency dividing, pwm generation and ppm generation.I'll look for something else.Anyway assuming you have the counters doing the work for the green lights, this is my solution for the blue led:two monostable, two NOT port and an OR port.Assuming there is still the flipflop.The NOT inverts the flipflop output and takes it to the trigger input of one of the monostables.This way, when you trigger your button, the flipflop flips, the not port inverts and you have a high pulse on the corresponding monostable.The second monostable has also its trigger inverted by the other NOT port, but the trigger signal comes from the output of one (or more using AND ports) of the green light counters: when the green light goes out, the inverted signal on the trigger input is high, and the monostable starts.And OR port on the two outputs of the two monostables, ensure continous operation of the LED.

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> I found the monostable operation, with which you pretty much solve> the blue led problem.> But there is no mention of counting abilities :(That's the point .. it is a timer, not a counter.When used monostable it will give 1 output pulse (with variable length in time) on each short input pulse.E.g. wire a buzzer to a push button: the busser wil buzz as long as you press the button.Now wire a (monostable wired) 555 between them. If you press the push button short, the buzzer will buzz for a time (according to the resistor and condensator value).If you wire it to an astable 555 the buzzer will go on/off/on/off like an allarm for as long as you do not reset the 555 (i think). That's how you can make a counter out of a 555. It will not count but it will generate a lasting block-wave.

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Then you simply use a 555 to generate a pulse train, and three counters as in my first scheme.The things i said for the blue led should apply.

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a puls train ?you mean i should use the 555 as a continuous puls generator and then use a counter to count the pulses ??why ??!!if I can make the 555 to output a singal that lasts 6 seconds, than that is just right for the green led !if I can make an other 555 to output a signal that lasts 8 seconds, that is just right of the green and blue led !I don't think I need no counter if I use the 555 monostable!

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Synopsis:initial status is everything offinstant 1, the button is pushedinstant 2 trough 3, led blue is oninstant 4, led blue goes off while green leds go oninstant 5, the button is pushedinstant 6, green leds go off and blue goes oninstant 7, blue led goes offEach "instant" can last several seconds at your choice.Now, the monostable keeps the output high for X seconds.Your green leds should stay lit UNTIL you press the button again.This means you can't use a monostable.You have to delay them lighting up, and during the delay you have your blue led on, but once the delay is finished and the greens go on, you have them on for an indefinite period of time.This means no monostable.Unless i got it all wrong :)

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Why not use a GAL? GALs can be programmed, erased, and reprogrammed to provide infinite logic models.Your circuit above is good, and most likely will work, but it's 'set in stone'. Any changes you need to make would require a new circuit design, a new PCB most likely. a GAL provides substantial flexibility without the requirement for hardware changes.I'm sure your school has access to a GAL Programmer and possibly some pre-written programs that you could look at. While a GAL might be overkill in this case and probably circumvents the original intent of the class to provide a solid grounding of discrete electronics, it might be something no one has thought of yet and therefore would be 'Creative'.

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----------(quote)Each "instant" can last several seconds at your choice.Now, the monostable keeps the output high for X seconds.Your green leds should stay lit UNTIL you press the button again.This means you can't use a monostable.----------The monostable keeps the output high for 6, 7 or 8 seconds. This high signal will turn on the blue led indeed. Since the monostables output is inverted (after the OR) by the NOT, it will keep the green led OFF (provided the "switch" is set to ON)When the "switch" (flipflop or whatever) is closed the input to the OR will be 1 and thus the output will be 1 for sure. Inverted bu the NOT that is 0 >> the green leds are OFF ! No matter what the monostable outputs.Now when the "switch" is opened, the output of the OR will depend on what the monostable gives as output. If it gives a 1 (for 6 seconds), the OR will output a 1 for 6 more seconds (inverted = 0 => leds stay OFF)Once the input from the monostable becomes 0 (after 6 seconds), the OR output will change to 0 (both inputs are 0) .. inverted via the NOT that is 1 so the green leds go ON.It is the monostable that gives the delay for the leds to go on, while it is the "switch" that ensures they go OFF.----------quoteYou have to delay them lighting up, and during the delay you have your blue led on, but once the delay is finished and the greens go on, you have them on for an indefinite period of time.This means no monostable.Unless i got it all wrong -----------You got it all right except for that last sentence "no monostable". It is the "switch" that keeps the green leds OFF, while it is the monostable that powers the blue one ON and powers the green ones ON( HOWEVER inverted) => keeps them OFF.I think it should be clear now.I am quite sure that my system works right :)

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if switch = on__if monostable = on____blue led = on____green leds = off__else____blue led = off____green leds = onelse__if monostable = on____blue led = on____green leds = off__else____blue led = off____green leds = off

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What is a GAL?By the way Philippe, this is for future:microchip's PICs can be programmed in visualBasic :)Well at least there is a basic for pics, in the form of a compiler called PicBasic.You may want to investigate this for your future cockpit works ;)

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Got it :)I am studing Automation (Bode Nyquist Nichols and their parents) i have my head full of block diagrams...Sorry for misleading and bothering you :)I beg your pardon

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Ok this brings up a few questions & remarks:1) what does a GAL cost ?2) tnx for confirming my cirquit is good :)3) i am not going to make a PCB, just a perfboard with wires4) I believe I can change times from teh 555's by chosing for trimmers and not resistors.Also "set in stone" is nor problem .. it is meant for my sim and it does exactly that which the F50 does so .. why would I want to change it :)Ok, now I need confirmation on a few things:1) the relais shown in the cirquit is wrong ?2) which components behaves as a switch then ? (i give a single input from the pushbutton and I need a "switch" to flip on, off the next time)3) how to calculate the resistor and condensator (what's the correct english word for these agian ...) values ?

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Lol no problemo ;)It only helps. I wasn't sure before, now I am :D

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>1) the relais shown in the cirquit is wrong ?A relais depends on the current on the coil: it will not hold the position when you release the button.Unless you are using a double coil relais, but in that case you'd need two buttons: one for each coil.>2) which components behaves as a switch then ? (i give a>single input from the pushbutton and I need a "switch" to flip>on, off the next time)flipflop, it's something like AND,NOT,OR ports: you find TTL chips with flipflops in them.One pulse on the trigger and they change state.CDxxxx or something like that.>3) how to calculate the resistor and condensator (what's the>correct english word for these agian ...) values ?That's my tricky part: i am experimenting for another thing that hasn't quite anything to do with planes (who said strobe light??? :-lol) and i found that the formula on my DS wasn't right.Or at least i wasn't able to make it work.Right now i am using it has an astable and getting fair enough results with 100ohm + 10k pot and a 220uf (polarized, as to say electrolitic) capacitor.With the pot i go from something like 80hz to 15s per cycle.And exact english words areresistor and capacitor :)

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New cirquit design:http://users.skynet.be/plipke/Schema3.GIFThis time the relais has been replaced by a JK FlipFlop chip. Both J and K will be kept high so that it behaves like a T FlipFlop (toggle).Then the cirquitry for the 555 timers has been modified according to most cirquits found on the net.

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