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alternating strobes for my car

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jakethepython

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can someone help me. i need to build an alternating switch for my car. i want it to be able to run 2 strobes at differnt times. so while one is blinking the other is off and it goes between the two every 2 seconds or so. i know how i would do it from a 555 timer. but i need to somehow do it from a car batterie which would blow the hell out of the chip. can anyone help me find a shcematic for such a thing?
 

McGuinn

New Member
Isn't the 555 rated up to 9v? This may explain it!

Otherwise, are you using the output of the 555 to drive trigger tranformers?
 

Phasor

Member
555 is rated up to 16V. Bear in mind, that a car's system voltage can rise up to about 15V, with the engine running fast.

For circuits, search for "555 astable".
 
Um, if memory serves me, don't most cars nowadays have a voltage regulator to keep the battery (and the alternator) at a pretty concise voltage, even at higher RPMs? Most times an electronic device can handle a 1-5 volt spike, depending on sensitivity of the device. It's the amps you gotta worry about most times. (Just my opinion, and bound to be flawed)

I'm looking to fabricate a very inexpensive lightbar, with 4 or 8 strobes. It'll most likely use 2 switches to turn on the lights if 8 are used. What I need is a shematic to alternate these, either with transistors or a relay (I'll duplicate for the second set of strobes). It'll have to withstand 12v. the Strobes are 12/24v strobes.

I'm not too savy on some of the more intricate devices, nor do I have a goodly amount of funds to put to it right now. Most of what I'll be using would come from Radioshack or the like, so bare that in mind.
 
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Andy1845c

Active Member
What exactly are you looking for? A traffic advisor? ( YouTube - Home Built Traffic Advisor Patterns ) Do you want LED strobes or xenon strobe tubes?

The electrical system of a car is a unfreindly place for some components. The voltage swings from ~12 to over 14v at times, load dumps can cause spikes in excess of 100v, lots of noise, ect. It all needs to be thought about for a reliable design.

You won't be able to make much of a lightbar for cheap. I have proved this. The video above is a project I made over a year ago. I learned alot doing it, but didn't save much money and am not 100% happy with it. I am working slowly on version 2 of the same project. By the time I am done I will not have saved any money, but will have a custom lightbar that fits in the headache rack of my truck.

That said, if your thinking your gonna make something reliably for pennys on the dollar, and have no electronics knowledge, I would advise you to just buy a commercail made product. If you want a fun project, and you don't mind re-doing/modifying it as you find problems, a light bar can be fun. If you need a bar of custom functions or dimenions, building will be the only way to get what you want.
 

Sceadwian

Banned
RIT huh, and you're asking how to use a 555 to power a higher load? Don't you have any classmates that take electronics courses? By the way, you need to be VERY clear on what your intent is here, why you're trying to do this is more important than what you're trying to do, due to the legalities involved in an automobile with blinking lights.
 
The strobes are actually old Fire signal strobes, that I have acquired from a job I did recently. I've seen them used on a Vehicle to decent effect, but not set up to purposely alternate. This is what I am going to try to do. I figured it's not going to cost Half as much to build it myself as it would to buy a commercial one of the same type. The only real costly part would be the housing for it. Wiring and switches I have, and some components for the actual circuit I have. All I'm asking for is a way to build said circuit.

I've built things that fail and I've built things that work, such is th way in homemade things. They work more times than not, and right now I don't have the money to buy it. As for why I'm doing it, for fun and possibly to use later on, for jobs. I know all about the Legalities of them, as I was an MP for a time, and me father is State Law Enforcement down here in Florida.
 
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Andy1845c

Active Member
I/we can't really advise you because you haven't stated exactly what you have. Are they xenon strobe tubes? Do they have a power supply built into them? How are they triggered?

If they are off a fire truck, I bet they are red in color.

In some places you can run red lights on your car if you are a volunteer firefighter or EMS. I can't think of any other legit reason to have red lights on your car.

Any job you get will provide the lighting. Putting red strobes on your car is not "fun" and is a taboo subject around here.
 
No no, not from a truck. I was doing work refurbing Portables for schools, and we junk the old fire alarms. I have 2 strobes that connect from that, the kind with the loud buzzer (which I promptly disconnected..eesh they're loud). I guess that'd make them Xenon tubes then. the strobe itself is triggered as soon as their is power to it. This is why I need to build a circuit to alternate current to the 2 strobes. I was thinking a relay, as it can easily handle 12v (or more) without too many extra resistors to cut the current. I'd hav to be able to hold current on each strobe for about 1.2 seconds to allow the capacitor to charge and discharge. I'm just not sure how to set up a relay (or transistor devices) to 1. Handle that amount of current, or 2. To not switch poles so fast when pwoer is applied.
 

Andy1845c

Active Member
Oh, okay, now I know what we are talking about. Something like this, correct?



Can you open one up and peek at how the tube is triggered? Any chance of modifying that circuit? Its possibly all SMD components or potted and if thats the case messing with it isn't going to be a good idea. If you can modify it, you may be able to control the trigger on the flashtube and not have to switch the line voltage on and off.

If you don't mind a relay cluncking away, it would be pretty simple to alternate power between the 2 lights. If you can find a relay with both NO (normally open) and NC (normally closed) contacts, you can use something like the classic 555 timer astable circuit to open and close the relay. With one light on the NO and the other on the NC contacts, when one is on, the other will be off.

Do some reading on strobe circuits and the 555 timer, relays, ect and post back if you have questions.

If you do open the lights and mess with them, be extreamly careful. Strobe lights use high voltage to operate and can give deadly shocks. Even with the power removed, the capacitors can hold a sizeable charge for quite a while.

Edit - just re-read your first post. So are these going on a car or truck? You mention 12/24v but then said they are from a building. Are they 12/24v AC or DC? I would lean toward them being AC if they are from a building. If they are AC, they won't work in a car.
 
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My buddy HAS used them on his truck. They're usually run with 24v, but worked just fine on his truck battery. but his all came on at once (he had 4). I have said relay, but it's only 6v max. I don't know how to adjust when the relay fires (slowing it down). Yes the pic is close, mine's just a different model.

I've opened it up and disconnected the jumper for the buzzer, but other than that I haven't looked terribly close. I know it has 3 connections on the bulb itself.

I'll look into the relay then, as I have now clue what a 555 astable device is (yet).
 
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Boncuk

New Member
Isn't the 555 rated up to 9v? This may explain it!

Otherwise, are you using the output of the 555 to drive trigger tranformers?
The power supply rating is from 5 to 15V.
 
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