Help with simple circuit

First, one needs TWO wires for a complete circuit for those lamps....

Perhaps the frame is the return wire (aka ground)? I know nothing about this application so this may or may not be the case.

James.

"MacGyver" schreef in bericht news: snipped-for-privacy@z14g2000cwz.googlegroups.com...

Sean,

You're confusing us as well. FAIK most wings have two tips so I guess you have one light for each tip. Furthermore all lights I'm aware off have two connections. So if you want to use one wire, what to connect to the other connection? Relais don't work with one wire either. Think you have to explain more clearly what you want to achieve. So what do you have, what do you want to add and what limitations or constrains do you see.

petrus bitbyter

It can be done with one wire if there is a conducting frame. (Think about old-school bicycle lights.)

Or if you cut the wire somewhere, put the light at the cut and use the two remaining ends to make a closed circuit ;o)

If the OP uses the word wire for cable then he might even be talking about a multi-conductor cable...

--DF

"Deefoo" schreef in bericht news:43429269$0$5407$ snipped-for-privacy@news.wanadoo.fr...

These - and other - assumptions crossed my mind too. But to give a usefull answer I need to *know*.

petrus bitbyter

first off, thanks for the reply... I have been racking my simple brain on this for too long.

I am only talking about one wing in this scenario.

right now there is 1 positive wire that runs through the wing to the green light & the wing itself acts as a ground.

The strobe piggybacks off of it & one wire goes to ground & the other goes to the same positive wire.

Now the switch controls both the strobe & the light at the same time.

Problem is: I want to be able to flip the switch once & have the green light come on. then turn off & on the switch again (within a second or two) and have bot the strobe & the light on.

I am thinking that a relay possibly a latching relay with some sort of capacitor out at the wingtip could keep the line charged for the coil on the relay just for the 2 seconds it takes to flip the switch.

If I leave the switch off, the capacitor just runs out & resets.

Hope this helps. I don't know how to post diagrams here but if you e-mail me at: snipped-for-privacy@cox.net I will send you diagrams that explain this even better.

Thanks again!

Sean Gallagher

I don't think that is legitimate in aircraft. I think the OP is heading for problems with the FAA, unless his craft is "experimental".

...Jim Thompson

The hacking should be relatively trivial with the exception of very old aircraft. The wingtip is generally removable with lebenty-dozen screws, and the last outboard rib is the first thing you see. The electronics is generally bolted to the outboard rib and the nav light is pigtailed through an inexpensive connector to the electronics so that the whole wingtip can come off without removing the nav light.

You simply do your electronics in a box that will fit the surface of the rib and you are home free.

Jim

Jim ...

I'll make you a deal. You don't guess at airplane answers and I won't guess at IC internal design, since it is obvious that neither one of us has expertise in the other's field.

The OP can legitimize such an installation without a lot of hassle...and should be relatively simple to design and approve.

Google on "FAA Form 337" and "FAA Field Approval" if you want more information than you really need. I would argue that such a modification comes under the heading of "minor modification" and is a simple logbook entry, but the installing mechanic can go the 337 / Field Approval route if (s)he wishes.

Jim Airframe and Powerplant Mechanic Inspection Authorization

You actually have four functions that are necessary:

Off Nav Light On Strobe On Nav Light and Strobe On.

Think about it.

Off is obvious

Nav Light On when flying in darkness in cloud. Strobes induce vertigo when you are in IMC, but the nav lights by law have to be on at night.

Strobe On would be daytime use when you want to be seen but not keep a $5 lamp burning for no good reason.

Nav Light and Strobe On for VMC at night when you need not only nav lights, but to be seen at a distance as well.

NOW the problem complexes itself up, but shouldn't be a problem with a few well chosen capacitors and a simple counter.

Jim

This is exactly what I want, thanks for the great description! With this circuit, I won't have to hack the plane at all. That's why I want to build it. It can fit in the fiberglass wingtip in a small enclosed box no problem. It is for an experimental aircraft, so no worries there with the FAA! Thanks so much for all of your posts.

I know exactly what this guy wants to accomplish. On one wing tip, he wants to mount two lights - the running light, and the strobe. He has one switched power wire, and the frame of the craft is the ground return. He wants circuitry at the tip end of the wing such that when he turns the switch "on", the main running light comes on. If, while the main running light is on, he turns the switch to "off" and then back to "on" again within two seconds, the main running light (which will have gone dark while the switch is off) will come back on _and in addition_, the strobe will come on, having been triggered by the 1 ms < x < 2 sec interruption of power, so that they'll BOTH be on now.

I've seen this switching logic function in a standard PIR porch light, only the "Strobe too" function would be exchanged with "turn porch light on unconditionally".

The circuit should be triviaL. The question is, how severely does the OP want to start hacking into his airplane? ;-)

Good Luck! Rich

Not too worried about having just the strobes on without the Nav lights... I don't think I would ever use the strobes without the Nav lights.

I just want to be able to have a way to turn off the strobes so I don't piss off other pilots while taxiing...

In article , James Morrison wrote: [.. wing ..]

If the wing is made of metal, it is the return path. Its a lot like what is done in cars.

In article , MacGyver wrote: [....]

With relays:

From switch --+----+------------+------------------------ Green light ! ! ! \\ ! ! R1 / ! ---------- \\ ! ! NC ! ! / ! ! O- ! - ! ------------------- Strobe ! !NC !

In article , john coates wrote: [...] Modified:

! ! ^ 15V ! ! ! ! ! ! ! ! !

The power in an aircraft is about as bad as in a car. Adding the 1K resitor and 15V zener protects the MOSFET from the high voltage spikes.

Lots of aircraft have lots of currents flowing in the skin. If the factory made it that way, getting rid of the current in the skin will get the FAA spun up.

Hello Sean,

I think the following circuit should do what you want. Switch on: Nav lights are on Capacitor was empty and charging but the lower MOSFET is conducting because its gate is drawn to 12V immediatly, thus keeping the other MOSFET non-conductive.

Now switch off and On again. The capacitor will not be discharged when the voltage returns, so the top FET is in conduction, now keeping the lower FET out of conduction while keeping the strobe light on.

You can play around with the 1M or 10uF to shorten or lenghten the max. time period between the two 'on' cycles of the switch. The FETS should be N-channel MOSFETS, select based on required lamp current.

Need further help? Let me know...

Regards,

John Coates Gent, Belgium

.--------------------------.----------------o-- | | | | diode | | V | | - 10k .-. | | ___ ( X ) strobe | o--|___|--o------| '-' | | | .-. | | | | | |1M o---' | .-. |+ | | | | | | | === '-' ||-+ | .-. 1M | | 10u=== | ||At least I think it is simple...

I don't know of any compass that doesn't use magnetic sensing. As for flux valve (remote sensing) compasses, the OP stated that it was a light aircraft. So far, after 40 years as a mechanic, I haven't found a flux gate installation for the primary compass in any airplane I've worked on or inspected. Rarely an autopilot installation, but a whiskey compass is standard on light aircraft AND heavies for that matter.

Any mechanic willing to sign a logbook entry without checking for compass errors after an electrical installation won't keep his ticket for very long.

Your "good practice" conflicts with Cessna, Beech, Mooney, Piper, Van, and half a dozen other players' "good practice". You have done certification work on light aircraft before giving your opinion, yes? You have your FAA and FCC certificates and such for both original certification, modifications, and maintenance, yes? You've at least bent one wrench on a light aircraft, yes?

That is just a plain stupid statement.

Jim