Strobe light

[TheAdrian]

This is not exactly anything new, but I have built myself a strobe
light controller:

Controls Luxeon III emitters for high intensity (500mA for strobe)

Single flash = battery good
Double flash = battery low
Continuous flash = battery critical

Decode a receiver channel to switch navigation lights

Drives 1 series pair of LEDs for strobe, up to 5 more pairs for navigation
lights

Pulse width modulation controls brightness (as the LEDs are so bright)

Size is 1.2" * 0.8"

N.B. the LEDs are rated as Class II lasers for safety purposes. They are
too bright to watch for long when close up. Their angle of view extends
to nearly 90 degrees either side of center.

I can upload PIC code, schematic, PCB if anyone is interested.

[medeiros]

Adrian I would very like to receive the project from you marcoantonio2004@terra.com.br

[Trikky]

I would also be very interested in this one as well.

trikky73 at iprimus.com.au

Chris

[TheAdrian]

Zip archive of project attached

[stu78]

...N.B. the LEDs are rated as Class II lasers for safety purposes. They are too bright to watch for long when close up. Their angle of view extends to nearly 90 degrees either side of center...


Nice project,
Can you give some more details on the LED's please. Where you got them, what the spec sheet says, how much they cost etc. I am trying to find the best LED's for night flying / nav lights, and these ones sound good.

Thanks

Stuart

[TheAdrian]

Nice project,
Can you give some more details on the LED's please. Where you got them, what the spec sheet says, how much they cost etc. I am trying to find the best LED's for night flying / nav lights, and these ones sound good.

Thanks

Stuart

You can get the luxeon emitters from Maplin. You could also try
Stellatus, or search on Ebay. Also prolight, which seem to be the
same. Specifications from Lumileds. N.B. Luxeon star is on an
aluminium heat sink, Luxeon emitter is bare. They are available in
both Lambertian and batwing radiation patterns. They are quite
expensive.

The setup I am building is really meant for daylight. For daylight you
need extremely bright point sources. I have mounted the strobe LEDs
on the canopy facing left and right, about 40 degrees forward of
abeam. I am also planning to add wingtip lights.

I am curious to discover whether the LEDs will be a useful aid to
orientation, and how conspicuous they really are against a bright sky.
I have tried hanging LEDs on a bush outside my house and seeing how
visible they are from down the lane, but it is not a very realistic test.

If you want to fly at night, your needs are a little different. You
ought to have enough lights to be able to deduce your orientation
from any aspect. That means at least 3 differently located LEDs
visible from every direction. I reckon that if your LEDs are angled like
the faces of a tetrahedron, you need at least 12 LEDs. One attractive
feature of the Luxeon LEDs is their wide angle of view, which makes this
easier. Most high brightness LEDs have quite a low viewing angle.
However at night you don't need high intensity lights. The aim
is to see your aircraft, not to dazzle yourself. So I think you would
be better off with diffuse sources, lighting up the outline or interior
of the wings and fuselage. I did consider possibilities like mounting lights
on the spats to illuminate the underside of the wings. Or a light in
the fuselage to diffuse through the covering. Regrettably, the wings
on my aircraft are transparent, not diffusing.


N.B. I had a chat with my boss about the circuit. (In his former job he
was quite a notable designer of audio amplifiers.) He recommended an
OSCON capacitor instead of the tantalum bead, to handle the high
ripple current.


See also http://members.misty.com/don//ledx.html

[stu78]

Thanks for the info, you are right, they are not cheap!

Do let us know how you get on when you fly the strobes/nav lights.

Last year someone at our flying field attached 3 ultrabright white LED's to his plane and they coud be seen very clearly as long as the plane was flying towards you! I think you will be pleasantly surprised at just how visible they are in the sky.

Stuart

[Acetronics]

Hi, Strobers

Some pictures from so little frenchies ... w/strobes from ... Acetronics !!!

http://perso.wanadoo.fr/mes-avions-rc/VID1.htm

Alain

[ElectoPete]

TheAdrian,

Nice project!
I am interested in building this one!
I checked the schematic and the PCB, using Diptrace (freeware).
The schematic was OK, but the PCB looked strange (several connections were missing -only thin lines).
I am not used to Diptrace - I just want to print the layout for etching. :confused:
Is the PCB double sided- with the missing connections on the reverse side - or what?

Pete

[TheAdrian]

TheAdrian,
Is the PCB double sided- with the missing connections on the reverse side - or what?
Pete

The 'missing' connections were hand wired with wire wrap wire
soldered on the underside. I was keen to make the PCB as small
as possible, and I didn't want to resort to another layer. DipTrace
has an option to view with or without the extra connections
(menu View/Objects).

Meanwhile, I have tweaked the code a little:

The strobe pattern is now
100100000000 ... Battery good
100010000000 ... Battery low
100001000000 ... Battery lower
100000100000 ... Battery lowest

If signal is lost, after for 4 cycles the navigation lights flash on/off
alternate cycles.

There is still one pin left on the PIC. I may yet use if for an
stall warning (angle of attack sensor) some day. There is a little
problem with making a very small light sensor and finding somewhere
to mount it out of the prop wash.

Now I am making little balsa pyramids with triangular aluminium
heatsinks to mount navigation LEDs on the wingtips.

[TheAdrian]

I made two little changes:

The receiver input to the pick (AN2) was picking up interference
from the motor control at about half throttle. This caused the lights
to go off. So I added a 100pF capacitor from AN2 to the 0V line.
(Even the capacitance of an oscilloscope probe was enough to
make the problem go away.)

The resistors were getting rather hot, being all bunched up together.
So I spread them out a bit.

Vonada's engineering maxims:

There is no such thing as ground.
A capacitor is a device for converting a voltage glitch to a current glitch.

[RussellK]

Has anyone tried the "Superflux" LEDs like these in a plane?
http://shops.bizarsoftware.com.au/ATAShop/catalogue/category16/category41/category86/category84
While obviously nowhere near the Luxeons, they are very bright and have a wide (~100 degree) viewing angle.

[westfw]

Thanks for the info, you are right, they are not cheap!
Lumileds recently announced significant price cuts on luxeon emitters and
stars; most dramatically in the 3W area, I think.
http://www.lumileds.com/newsandevents/releases/PR45.pdf