strobe light schematic

[Guest 4aplat]

Hello SAin

 

I try the kitplanes schematic to get an idea of what I can get.

 

But the article is 2 years old (and the schematic has got some mistakes)

 

and 2 years is to much in new technologies so I use a "power led" (just have to switch the led on it)

 

the first 555 is for the flashing the second one is for stoping the lignht during 1 sec

 

MicheL

 

 

[Guest 4aplat]

I have to mesure the "voltage" of each led to know if it's possible to switch 4 in line

 

I Suppose it's about 3.4 V

 

So 3 leds need 10.2 V and 4 leds need 13.6 V

 

As the power is to be 2 V more than what need the leds, I think it's not possible to get 4 leds

 

So i will test with 6 leds (and 2 circuit) in each wing

 

here is the led driver data sheet

 

http://www.xppower.com/pdfs/SF_LDU.pdf

 

MicheL

 

 

[sain]

It'd depend on what high brightness LEDs you used. Essentially the voltage into that LED driver has to be 2 Volts higher than whatever the combined forward voltage drop of your LED chain is.

 

I think (guessing a lot) that MicheL has some Cree EZ1000 LEDs, which have a typical forward voltage of 3.3 (max 3.8). So his numbers are pretty much bang on.

 

That said you could always use 2 LED drivers in parrallel. not sure what the cost of those drivers are. probably fairly cheap.

 

MicheL did you build the specified input filter?

 

 

[Guest 4aplat]

the leds are : "Cree XR-E 7090 R2, white, 242 Lumen with pcb (star)"

 

forward voltage is 3.7 V

 

the led drive price is 15 € with VAT (12 $ (usd)) and I have buid the input filter

 

 

[sain]

You might want to try firing up your radio from the same voltage source (battery) and seeing if there is any interferance before bothering to make the filter. I suspect it'll be necessary, but your radio may already have nice filtering.

 

Nice job though MicheL, it looks like that will work very well.

 

 

[Guest 4aplat]

I've got an ICA3 radio on bord

 

I never use it as I don't get the licence

 

but I will test it as soon as I would be able to test the leds in the avid flyer

 

MicheL

 

 

[Tony2]

 

NTBA

 

 

[sain]

hmm.. a bit wrong with that schematic.

 

First of all, a 2n2222 is a NPN transistor not a PNP as shown in the diagram... A PNP transistor would work from that schematic though. Secondly the brightness level required to get near to compliance with standards means you need a LED much like the one 4aplat has specified. A 2n2222 will turn itself into a gas if you hook up any more than 1 of the CREE XR-E 7090s to it.

 

Interesting use of the flasher LED though, that wouldn't have occured to me.

 

*edit* actually I'm pretty sure that circuit wont do squat - try building it with http://www.falstad.com/circuit/

 

Roughly speaking LEDs will be at the peak brightness when they are supplied with the current they require. The LED driver MicheL is using will provide that constant current despite the variable voltage of the aircraft's power supply. Essentially it wont matter if hes talking on the radio or starting or whatever, his LEDs will still put out their maximum brightness.

 

 

[Guest 4aplat]

HI

 

I will try another solution

 

I still use a 555 or 556 for the flashing a mosfet (I need 4 to 6 A) and this led array

 

BRIDGELUX - BXRA-W1200-00000

 

 

It works with 14 V so I won't have to use a driver and it is much more powerfull than the luxeon

 

 

[sain]

ummm... have you bought those yet MicheL? the datasheet (http://www.bridgelux.com/assets/products_portfolio/BridgeluxLEDArray_DataSheet.pdf) gives a minimum voltage of 15V. You may need to build a boost converter to go with them.

 

 

[Tony2]

NTBA <<<< that is the address with more about the circuit

 

Your right about the transistor with that circuit you can go with a Darlinghton to handle more power and keep the parts count the same .

 

The key feature was the 1 second timer *flashing led*

 

 

[Tony2]

There is also a cree with 4 dies brake the tracks put them in series via the flasher with a 50/50 cycle should be ok

 

 

[sain]

The flasher LED is certainly an interesting idea, and would probably be a very simple way of making an oscillator. However that circuit, as shown on that page wont work even if you do sub in a pnp transistor. The designer has put in all the LEDs backwards for starters. Check Simple LED Circuit | TechDose.com

 

for a guide on how to hook up an LED.

 

 

[Guest 4aplat]

http://www.bridgelux.com/assets/products_portfolio/BridgeluxLEDArray_DataSheet.pdf) [/url]gives a minimum voltage of 15V. You may need to build a boost converter to go with them.

the 1200 needs from 13 to 15 V

 

in flight the battery delivers 14.5 V and it will be ok

 

 

[tangocharlie123]

Just had got this from the KR2 email

 

http://www.barkeraircraft.com/files/Low_cost_Aircraft_Strobe_lights.pdf

 

Maybe it will help but not led's

 

Cheers

 

 

[sain]

impressive ingenuity - using a disposable camera's flash for an aircraft strobe.

 

I imagine the 555 timer portion is fairly similair to 4aplat's.

 

 

[Guest 4aplat]

I'm with Tomo. If you want the lowest price, go an Automotive flasher. It will plug straight onto your battery. Planes are 12V aren't they ? Yea i am pretty sure they are (feel free to correct ) Most are capable of driving 2 23W globes, so any number of LEDs will be fine. They are abundant (Super cheap auto or equiv will sell) And easy to replace. With a simple circuit that anyone could build.

planes cars and boats are 14.5 V and not 12 !!

 

 

[Guest davidh10]

planes cars and boats are 14.5 V and not 12 !!

They are called "12 Volt", except for the 6Volt ones... are there any of these left or are they now vintage? Trucks are mostly 24 Volt.

 

Note that this is a nominal voltage that will be delivered at the terminals of a healthy battery that is not under load and has not just been on charge in the last hour or so.

 

Batteries terminal voltage decreases due to the following factors:-

 

• The level of charge. As the battery is discharged the terminal voltage will decrease. The amount is dependent on the battery technology. For example you may find that your 12 volt gell cell or lead acid battery only delivers 11 volts when approaching a discharge state. Eventually it will drop very low ans that is usually when damage occurs. Another example is a torch battery. The typical 1.5 Volt battery will still be considered to be functional until the terminal voltage drops to about 1.0 volts. Lower in some devices.
   
   
  
• Age of the battery. As it gets older, the fully charged voltage will slowly drop.
   
   
  
• When a load is applied to the battery. All batteries have internal resistance, so when a current flows, you get a voltage drop across that internal resistance which reduces the terminal voltage. Most 12 volt vehicles have a 7.5 volt ignition coil with a ballast resistor that drops the rest of the terminal voltage while the engine is running, but is bypassed during engine cranking because the huge cranking current can drop the battery terminal voltage to around 7 to 8 volts. Particularly once the battery gets a bit of age on it.
   
   
  
• Temperature. Battery output voltage usually drops with temperature. That's one reason a battery that has been in freezing conditions has a harder time cranking the engine. The other of course is thicker oil, but both contribute to harder starting.
   
   
  

 

 

So this brings us back to the 12 volt battery and you need to charge it. If you try and charge it with 12 volts, the two cancel out and no current flows. hence charging circuits must deliver a higher voltage. Often in the 13.5 to 14 volt range. Higher than this can cause premature light bulb burn out and may damage some electronics, although most 12 volt electronics is designed to accept inputs that will deal with a range of input voltage between about 9V and 15V.

 

Now lets move out away from the battery, and through the wiring. The wiring has resistance too, so when current is drawn, there is a voltage drop along the wire. When you are talking about transmitting power to wing tips or tail, you may have wire lengths approaching 10 metres. To calculate the voltage delivered to the load, you need to take into consideration the voltage drop from the battery to the load. If you cannot tolerate a reasonable loss, then you need thicker wire that has a lower resistance, but the same applies. There will always bee some drop and you don't need the extra weight of using battery jumper leads to minimise the voltage drop.

 

As previously indicated, my calculated wiring loss for AveoFlashLP using 21 AWG wire is approximately 2 Volts (with the current drawn by the strobes being 1.56 Amps each) but they work down to 9 Volts so that is OK. Even if the battery charging fails, there will be enough voltage to drive them. The 13.7 volts that the system delivers with the battery charged and the engine delivering charge is also OK, since they work up to 32 Volts.

 

Bottom line. You have to design and calculate all aspects of the solution if you expect it to work over all operating conditions.

 

 

[Guest davidh10]

Just had got this from the KR2 emailhttp://www.barkeraircraft.com/files/Low_cost_Aircraft_Strobe_lights.pdf

Maybe it will help but not led's

 

Cheers

Very innovative and a great breadboad design for bench testing, but to stand the vibration in an aircraft needs to be better built.

 

The tacked on components and mid air soldering look very reminiscent of the exhibited bodgy wiring jobs written about by CASA in the May-June-2010 edition of flightsafety magazine. I'd recommend reading it.

 

 

[Ron5335]

New Technology Is Here

 

While everyone was trying to work out what was the best way to do it, It's been done.

 

In a 1" wide x 5/8" high clear dome, they have places 6 x 1 watt LED'S (Heads only) & it is the equivilent to an 80w strobe (So they claim).

 

You can get them in sets of 4 for around about about US$200.00 & includes the strobe driver unit, or individual domes with an inline lasher unit for US$65.00

 

The single units meet the Specs for a Non RFI emitting device.

 

 

[sain]

commercial units are available all over. I suspect you can even get some from Ian at clear prop (because Wicks aircraft supplies sells them).

 

Personally I think $200 for 6 1 watt LEDs is a rip off, even with the circuit to make them go blinky blinky and the nice clear dome. I've seen LED anti-collision lights for over $1000 (wicks for example), which is just insane.

 

 

[Tony2]

5 watt ? ?lux built in strobe 2 bulbs for $50 6 led

 

LED strobe light by Putco T10 194 168 Wedge bulb

 

https://www.youtube.com/watch?v=b159kJDdPWU&feature=player_embedded"

 

hite Led strobe light high power flashing Putco wedge 194 168 t10 t20 flashing 6000k SMT led bulb

 

Special Note:

 

6 High Power SMT LED's per bulb <br> (Price for one pair) / Super Bright White Color is 6000k - PAIR

 

This is a PAIR of led strobe lights Wedge Bulbs Putco's 5 watt LED strobe light pulses at 4 times per second.

 

No driver needed. Strobe driver is built into the bulb circuit board.

 

4 Strobe flashes per second by on board programmed IC memory chip.

 

DC 12 Volt

 

Electric current 65 mA

 

SMD 5050 6 chip pc board.

 

6000k White color temperature

 

25,000 hour warranty

 

Useful for commercial vehicles, snow removal vehicles, emergency vehicles, fleets, and any application where a warning indicator is useful or required.

 

LED strobe light by Putco T10 194 168 Wedge bulb.

 

 

[Ron5335]

Putco T10 194 168 Wedge bulb part # 16162

 

Tony,

 

Like you I'm searching for the best solution.

 

I made contact with Putco in the US, & that part number is obsolete, along with part itself, however there are agents over there still clearing out their stocks.

 

Ron

 

 

[sain]

I'm not really suprised - i suspect in reality that putco strobe doesn't flash very brightly. The electric current is a bit of a give away - most high output LEDs will draw much more than that - for a 6Watt output you would expect to see at least 500mA or so.

 

For those after a commercial, off the shelf unit one of these has been stuck on an aircraft before:

 

Clear Security Strobe Light SL-126 Clear - Smarthome

 

the $15.61 price tag is pretty hard to beat.

 

The post here: Voltage regulator options discusses it briefly, along with a voltage regulator to go with it. I'd be more inclined to use a low dropout voltage regulator, but the one suggested in that post should work (and apparantly does).

 

*edit* whups, thats not an LED strobe. my bad. still not bad though.

 

 

[Guest 4aplat]

I'm in holidays in Singapore so I don't have the data-sheet with me but I remember that my prototype uses 1 Amp or may be 1.2 A

 

guess it's more bright than the 65 mA one !!!!

 

it's easy to show a video in the dark. but most of us use to fly in daylight