View Full Version : type of switch

Mr. Midnight
04-19-2007, 07:54 PM
hello folks im tring to wire this curcuit up and im wondering what type of switch this is , and if im hooking it up right.

i believe it is a single pole double throw is it not. the curcuit is from this website.

i have built this curcuit twice and i get the same reaction with the red led staying on all the time.

im wondereing if i have the switch connected properly.

im using a breadboard now so that i get it right before i solder.
all parts are correct, however if wired right:).


Bob Reed
04-19-2007, 08:20 PM
Hey Robert the link you sent does not work. If the light stays on all the time then you are correct something is amiss....

Mr. Midnight
04-19-2007, 08:37 PM
sorry about that i thought i got the link working, ill try again.

Mr. Midnight
04-19-2007, 08:42 PM
i think i got the link to work thru the forum, sorry...................www.simprojects.nl/gear_up_down_indicator.htm


Michael Carter
04-19-2007, 11:44 PM
Hi Robert, I received your e-mail, but I'm afaid I can't be of much help with the circuit; I haven't built it yet as I'm not that far along.

To me, the switch also appears to be a SPDT type switch. I'm using those type switches in my current landing gear panel. If it is not, I don't know what type it is. Upon looking at this schematic further, I'm curious as to where the third leg of that switch is supposed to be grounded.

If you write to the author, he will answer. He answered my questions about eliminating the 220 and 680 resistor to power 12VDC bulbs in place of the LED's.

Bob Reed
04-20-2007, 01:08 AM
Hey Robert. Unfortunetly I can not read too much in those funny drawings.. (schematics.. I know!!) But if they are driving the red and green leds one side of the switch would turn the green ones on and the other would turn the red ones on .. Right? Or are they using 2 switches for that? If they are using 2 switches then yes one way should be on and the other off.. How do you have the switch wired? And if you do not mind me asking.. Why are you doing it like this? Hey Westozy you could do it like this! Take a look at the schematic.

Mr. Midnight
04-20-2007, 04:48 AM
No problem im trying to acheive as much as possible the way 737 landing gear lights operate.

i dont want them to just turn on then off, i want the red and green lights to operate just like on a 737ng.

i also have a 8/8 and a 16/16 phidgets boards and im still learning them.

this curcuit seems to create somwhat that effect.

so a separate curcuit would be nice if possible.
im working on the landing gear lever right now and i cannot move forward until i get this right.
everything is ready and all i need to do is get the lighting effect correct and then i can install it in my MIP.


04-20-2007, 12:42 PM

While monostable timers are not my strong suit I do have 30+ years in electronics, so if you want I'll try and help.

My first question is whether or not the green lights are working correctly. Do they go off immediately and stay off when the gear switch is up? And when switch is placed in the down position it takes about 5 seconds for them to come on?

If the answer is yes then let's start finding the problem. What does the red led do if you disconnect the diode from pin 10 of the chip and operate the switch?

Let me also ask a different question. With this circuit all the gear lights come on at the same time, a scenario that might not be totally acurate? I have seen a schematic somewhere on the web that turns them on individually at slightly different intervals. I have been searching through my files and I must not have saved a copy. In mt pit I've programmed a PIC to ramdomly light the green LED sequence and control the red.

Let us know what you find out about your circuit and we'll go from there.


Mr. Midnight
04-21-2007, 01:36 PM
Thanks for your help terry, I thought I was pretty good at making circuits but it has been awhile.
This will be about the eight time I built this circuit and I get the same effect.
The red light will stay on and if I move the switch the red and the green lights will stay on.

Im pretty sure of the correct parts, and I have gone out and bought some more and the electronic person assured me I had the correct parts.

So far this circuit will fit what I want it to do, I like the idea of it working separate of my phidget cards(still trying to learn them),

I would like to find a circuit that will mimic the up and down lights of a 737 or something close, and I believe this one does, if I can get it to work.

Let me also ask a different question. With this circuit all the gear lights come on at the same time, a scenario that might not be totally accurate? I have seen a schematic somewhere on the web that turns them on individually at slightly different intervals. I have been searching through my files and I must not have saved a copy. In my pit I've programmed a PIC to randomly light the green LED sequence and control the red.

That is true but im thinking once I get this circuit to work I can add a 555 timer to each red and green diode to get the effect I want, you know like the center bay red light would go out sooner than the outside bays.

I know this is starting to get complicated and im sure there is a easier way im sure to get this done, but what im finding out about this pit building is that once you have decided a way to go you must stick to your or plan you find yourself going in a deferent direction with deferent problems.

Oh and the red light stays on if I remove the diode from ten.

And this PIC programming , what is that about, I have no programming experience but I am learning now from home.


Bob Reed
04-21-2007, 01:52 PM
If you have Phidgets why do you not just read the offsets and let FS do the indicators for you? This is all programed into FS already.. Why remake the wheel? Or do you not have an output card and have no intention of getting one? Curious minds want to know??:)

Mr. Midnight
04-21-2007, 02:16 PM
yes as a matter of fact i do own the 8/8/8 and the 16/16/, i guess i can go at it from that angle and i should in fact.
im wondering though can i run test to see if it works without running the sim software or do i have run run the sim to tset.
im thinkin i do and that will be alright, i have been weary of using phidgets because of the learning curve so i guess had better get started.

i will reload the new phidgets software and give it s try.

Bob Reed
04-21-2007, 02:44 PM
Well learning is a pain.. Like right now I need a list that I have used 100 times but I do not use it every day and I can not for the life of me remember which document it is in! Grrrrrr more lost time hunting... But.. You will find it will be no more time lost learning Phidgets then trying to get a circuit to work... And if you are going to use the output card anyway.. No time like the present to get started! There are lots pf people to to help as well. And I think there is some testing available in Phidgets but lets face it the question is, does it work when FS is running?:D;)

Mr. Midnight
04-21-2007, 02:57 PM
yes that is the question, and i believe you do but im not for sure, if so i will have to go at it from another angle, i wanted to get this landing gear problem behind me so i can move on to the next stage and that is painting and framing the MIP, and setting up PFD and the ND from FSEXPAND.

now i see why this cocpit building takes months and years to get to where you want it:)

Bob Reed
04-21-2007, 03:01 PM
Well I am running my landing lights that way. I am just using the FS internal programing (through my interface) and I get the staggered on and off that you are looking for. And better yet when they lock I get the "thump" in the floor from the sound. That is the idea behind interacting with FS. The entire sim reacts to what is going on in FS...

04-21-2007, 09:59 PM

If I understand you, when you move the switch to the "down" position you get both red and green immediately and there is no time delay before the green turn on. Also, when you move the switch to the "up" position the green immediatly goes out and the red just stays on. So no matter what you do the red is always on and it just looks like you are flipping a switch and operating the green. And, this is important, is there no time delay at all when turning on the green?

If that is correct then leave the diode disconnected from pin 10 and lift the diode off pin 6 and tell us what happens. The red light should no longer light.

Actually I'm suprised that the red led remained always on after the diode was off pin 10. I don't think the timer is running/reseting.

Also, have you wired the relay and 300uf capacitor to the key board?

A couple of things you need to be carefull of.

Those 10uf caps connected to pins 1&2 and 14&15 have polarity and you need to connect them correctly.

Make sure pin 12 is connected to ground.

Also pin 16 goes to 12v and pin 8 goes to ground.

To answer your question about my pit, I always go for maxium eye candy. So I have white and red leds in the end of the handle. The white goes on with the pits backlighting, the white goes off and the red blinks whenever the gear is in motion. As the gear either go "down and lock" or go "up and close" the three green leds(located on the panel next to the handle) come on one at a time. If down they stay on, if up they slowly dim out after about 30 sec. As soon as we have an "all three green situation" the red goes out and the white comes back on. Kids love to play with that big lever and make all the lights blink.

Let us know what you find..we will get this running.


Mr. Midnight
04-21-2007, 11:23 PM
Thanks Terry i really appreciate this, im kinda wanting to get this done now and figure out what im doing wrong .

i removed pin 10 and the red lite stays on but it did dim a little, and then i removed pin 6 and the same thing happened.

as far as polarity on the caps im sure i have them in corecctly, on the 10uf caps the one end with the negetive or short end goes to 15 and 1.

as far as the 300uf and relay i did not need that curcuit for im going to operate the gear key from another source, im sure that curcuit is for this curcuit to operate your g key and run your lites.

so the only wire that i have connected to the center switch is coming from the 10k and 1 k resistors.

i hope that not adding that 300uf and relay is causing the problem.

i thought that was to power the relay which in turn pushes the g key.

so from my procpective that 300uf and relay has no effect on my miss wiring or what ever im doing wrong on this curcuit.

04-22-2007, 10:45 AM

First le me say that I agree with Bob and in the end you you be the most happy using a circuit that interacts with FS.

Having said that, we continue. You haven't answered the important question. When you flip the switch to lower the gear is there a time delay before the green leds turn on? I don't think the timer will run so I doubt there is.

You are correct the 330uf cap and relay aren't needed and would have be the next things to disconnect. Also, we are trying to isolate parts so when we disconnect a part we leave it disconnected. From your writing I think you reconnected the diodes to pins 6 & 10. Leave them disconnected. Do you still have the red led on?

We are now working only with the top of the schematic and need to double check each pin of the timer.

Pin 1 - negative lead of 10uf cap only
Pin 2 - positive lead of the same cap and 470k resistor that in turn goes to +12
Pin 3 - goes to +12
Pin 4 - the 1nf cap that goes to ground and 1k resistor that in turn goes to the switch
Pin 5 - goes to +12
Pin 6 - for test purposes, nothing connected at this time
Pin 7 - the negative lead of diode that in turn goes to the base of the transistor that controls the green leds
Pin 8 - ground and the .1uf isolation cap
pin 16 - +12v and the .1uf isolation cap

The rest of the pins we'll worry about later.

Ok, recap, we are trying to get the red led off, checking for a delay of the green leds on, and double checking the top of the schematic.

What did you find.


04-22-2007, 12:30 PM
Hi Robert,

if there is no connection to Pin 6 and Pin 10 of the IC and still the red LED is on, I΄m almost sure you have either a defect transistor (BC548C) or it is a wrong type (BC548C is a so called NPN transistor) or it is wrongly connected (E,B,C). Make sure you are not using a PNP type. Not necessarily it needs to be 548C, any other small power low frequency NPN transistor will do.
To check whether the transistor is working properly just connect the bias of the transistor to ground- the led should get dark- if not - the transistor has to be replaced.

This is the first thing you have to correct. Then we will see if the rest is ok.

Hope this helps a bit.

Good luck