Anuther lektwonix kwestyun

MChalkley · Jan 17, 2002

I'm on a real "take more than I'm giving" roll on TBN lately, so in the interest of continuing that trend, and futhering the visibility/safety of my flashers on my EF-5, I'd like to ask the resident electronics gurus (Al, are you out there?) another question.

I mentioned in the thread on strobes that Bob started that Whelen has a "pulser" module for flashers. I'm not exactly sure what it does, but I suspect it produces 3 or 4 flashes a little longer than the "persistence of vision" duration (what is that, 1/23 of a second or so? I forget...), interspersed by off cycles of about the same duration, followed by the balance of the 2-second-or-so on cycle, followed by a 1 second or so off cycle, then the whole thing repeats.

Obviously, you can't do this with an incandescent bulb, because they aren't fast enough. My question is: How tricky is it to design a circuit to do this? And how much would the parts cost? Ok, that's two questions, but you guys have never been strict on that before...

TWINKLE_TOES · Jan 17, 2002

Mark,
Al, are you out there?

Well, just barely. I'm about ready to fall asleep waiting for 100K. Most strobes use a xenon tube and a trigger transformer to discharge a high voltage capacitor (300-400v) into the tube. Just like the flash on your camera, just runs periodically. I have built several when the kids were into launching rockets. Circuitry is simple and you can buy kits, Edmund Scientific and others for less than $20. I don't know anything about a "whalen".
Al

MChalkley · Jan 17, 2002

Whelen makes a lot of lights for emergency vehicles. But one of their options, and I don't know what they charge for it, is a pulser-flasher like I described that works with any kind of LED light. It's not a strobe, but it generates a strobe effect, just by pulsing the output to the LED. At least, that's what I think it does, based on a description I saw somewhere on their web site.

Anonymous Poster · Jan 17, 2002

<A target="_blank" HREF=http://strobeguy.safeshopper.com/specials.htm?210>Strobes & More...</A>

Flash 3 Headlight flasher

Product Details Stock #: Flash 3

The FLASH-3 does a standard back and forth wig-wag type pattern at a rate of 3 flashes per second.
Special: $35.99

Mark,

Here's something that may work with your nicely designed and existing rear light array...
{and you can still add some Whelen strobes...}

TWINKLE_TOES · Jan 17, 2002

Mark,
If all you want to do is pulse your LED lights in a strobe fashion that is no big deal for just LED's, but I think you mentioned that they had some other stuff in the light which allowed a constant illumination across a broad voltage range. In that case it may not be quite so simple. I have built a fish finder the mimics the operation of the old style neon light rotating on a motor. In that application to get a reasonable amount of light output I pulsed the LED's at 5 times the rated current but a very low duty cycle.
Al

RPM · Jan 17, 2002

I'm guessing the fancier ones have an IC in there to control the timing also. If I remember my personal ancient history there may be a few calculations necessary to get the right capacitor for the circuit - otherwise you won't get flashes of uniform brightness on the strobe - i.e. need to take into account how quickly the circuit charges before you can discharge it again.

A bit more trickery with the IC and dip switches would allow you to control how many pulses in a group and the time between groups.

My electronics knowledge is dusty though. Best bet is a local enthusiast that has a permanently warm soldering iron. Components would be cheap - it's just a niche application.

Patrick

TWINKLE_TOES · Jan 17, 2002

RPM,
Best bet is a local enthusiast that has a permanently warm soldering iron. 

Well put, and sound advise /w3tcompact/icons/smile.gif
Al

MChalkley · Jan 17, 2002

Twinkle_Toes - Hmm. /w3tcompact/icons/hmm.gif You're right - I had forgotten about the internal circuitry. All it is though, is a power supply circuit. It ensures constant voltage at to the LEDs, as long as the input voltage is between 8 and 32 volts. So it shouldn't be affected by pulsing the input voltage, as long as it was a "digital", or square wave pulse, right?

TWINKLE_TOES · Jan 17, 2002

Mark,

So it shouldn't be affected by pulsing the input voltage, as long as it was a "digital", or square wave pulse, right? 

That should be right, so long as the supply has no energy storage (capacitors) of consequence. Give it a try by touching the hot lead to the battery lead and see if the LED illumination follows the contact bounce.
Al

MChalkley · Jan 17, 2002

Al - It appears to, but I'm not exactly sure what I'm looking for. When I was messing with them earlier to take the pictures, they snap right on, and if you scratch the lead across the terminal, they flicker very quickly.

TWINKLE_TOES · Jan 17, 2002

Mark,
Sounds like it otta work. Wnat some homebrew circuits to try?
Al

MChalkley · Jan 17, 2002

Sure, Al! You know me - I'm only here for the handouts, anyway. /w3tcompact/icons/grin.gif

TWINKLE_TOES · Jan 17, 2002

I'll see what I can come up with.
Al

MChalkley · Jan 17, 2002

Al - Thanks!!!

MChalkley · Jan 18, 2002

John - I took a look at the strobe site you posted a link to - some interesting stuff. Wigwag, huh? I guess that would be pretty effective, too. Can't you just see somebody behind you when you switched from regular flashers (if they were wigwag type) to a regular "Kubota-style" turn signal (where the turn side continues to blink, and the other side goes solid)? By the time they figured out what you were doing, they'd need psychiatric help. /w3tcompact/icons/laugh.gif

RobertN · Jan 21, 2002

Mark, try out:
<A target="_blank" HREF=http://www.galls.com/index.jsp>http://www.galls.com/index.jsp</A>
Look under warning lights in "Shop by Category"

SteveV · Jan 21, 2002

We might need to make a mechanical comparision here. The Led's are installed and look good. If you were putting the 4 in 1 on the front as an add on, would you economize on the spool valve?/w3tcompact/icons/hmm.gif Probably not. Yes you could home brew the electronic control to get the turn signals combined but the time involved is excessive, especially with the 'bota black box unknowns. Since the LED's are devices that will operate directly from a plc, /w3tcompact/icons/cool.gifwhy not use one. From my industrial control days, having a standard i/o to deal with makes thing a lot easier. Somebody else figures out how to deal with changes in battery voltages, reset and startup condtions. Then you can tell the thing what to do with software. If you don't have industrial connections, the programmer box is a significant chunk of change. The 24vdc Allen Bradley of late 80's vintage that I used in machine tool apps was programmed with a software package through the serial port. The controller with 8 i/o points was around $350. How bad do you want those turn signals combined? SteveV/w3tcompact/icons/smile.gif

Anonymous Poster · Jan 22, 2002

how about something like these Whelen products:
70285
MODEL 70285 SERIES
FAA-PMA APPROVED

The model 70285 Series is a self-contained Comet Flash strobe anti-collision light. It utilizes the same lens/reflector and strobe tube as the model HRCFA, however, its vibration resistant, heavy-duty construction is specially designed for Helicopter applications. It has a fixed mounting adapter, and an ms input connector. Available in three different Lens colors, Aviation Red, Aviation White, and Split Aviation Red/White. Also available in radio shielded configurations. FAA approved as a direct replacement for any Rotating Beacon that uses a 3-3/4" dia. Mounting hole. Unit will operate between 10 to 30 volts DC.

SPECIFICATIONS:
Power Consumption: 3.2 Amps @ 14 volts DC 1.2 Amps @ 28 volts DC
Weight: 1.5 lbs. Height: 8.0" Diameter: 3.7"
Drawing Number: 70285
Model Number: Part Number: Description:
7028521 01-0770285-21 shielded, Red lens
7028522 01-0770285-22 shielded, Red lens w/.31 mask
7028523 01-0770285-23 White lens
7028524 01-0770285-24 Split Red/White lens
7028525 01-0770285-25 Red lens
7028526 01-0770285-26 shielded, Red lens w/.29 mask
7028527 01-0770285-27 White lens, w/lock wire
7028528 01-0770285-28 shielded, Split Red/White lens

SA,CF
MODEL SA,CF SERIES
FAA-PMA APPROVED

The model SA,CF Series is a self-contained Comet Flash strobe anti-collision light. It utilizes the same power supply & housing as the model HRCFA. It uses an Aviation White glass lens only, which is ideal for agricultural applications where chemicals are used. Because the lens has no optics built in, it produces 300 effective candlepower. It uses a 3-3/4" dia. Mounting hole. Fuselage installation requires the A440 mounting adapter. Unit will operate between 10 to 30 volts DC.

SPECIFICATIONS:
Power Consumption: 3.2 Amps @ 14 volts DC 1.2 Amps @ 28 volts DC
Weight: 1.5 lbs. Height: 5.50" Diameter: 3.7"
Drawing Number: 70030
Model Number: Part Number: Description:
SACF 01-0770030-01 Aviation White lens

MChalkley · Jan 22, 2002

newby - Pretty neat, but I'm usually flying a little lower than I'd need to be to get into the FAA's jurisdiction. /w3tcompact/icons/laugh.gif "Designed for helicopter applications"... Hmm. I'd also be afraid it might tarnish my reputation to put something that strange on a tractor... /w3tcompact/icons/wink.gif