lightbar........ha,ha,ha

I'm a retired police chief with over 35 years service to you guys. On retirement I had the idea of building and providing a low cost, emergency lightbar for Volunteer Firefighters and police officers. I'm trained in mechanical engineering (not electronics) and I thought I'd be able to find a complete schematic for the electronic end on this or other sites. Big joke. So far its been rambling about "be aware, you can't have a red/blue light in your car blah,blah,blah." Nobody has offered or provided a complete schematic for an emergency lightbar from the 12V input to the final LED. No controllers, pattern changers, or any of the needed info. I get the impression none of you KNOW how to build one. I don't need "use a pic" or "try a microprocessor". Show me complete diagrams and I can build it .Maybe you can't. Leave it up to Federal or Sho-me or Whelen. Let them charge $ 900-1000 for probably $100 in parts. Us little guys can take it. Thanks for no help. If you want to rant about mypost....RetiredLawman@gmail.com

There are several designs on this site, and one in progress for a little kiddy car (might be what you are looking for) . I built one for my dog's collar using an ATtiny13v. It's not tough to figure out, just not many people have use for them, and we do have our own projects occasionally to work on. Don't think most people here, really want a full size, fully, functional, commercial grade police light schematic readily available. Kind of business-killer for you, plus we get tons of kids who think it would be a cool addition to their ride. Week ago, we had some nut case get busted in Orlando, flashing lights, uniforms, few other pieces of equipment in his SUV.

Anyway, nice way to ask for help, maybe somebody else will. Did my part on this last week...

Oh yeah, a programmable chip would really be your best bet, since once you get the pattern and timing you want, you can burn as many chips as you want. Simple, and easy to reproduce. A circuit with several ICs and quite a few other parts, would be much harder to reproduce, troubleshoot, expensive, and probably not as robust in a patrol car environment. More parts, usually mean more things that can fail. Also much less to learn, if you are starting from zero.

https://www.electro-tech-online.com/threads/police-flash-lights.103089/

Retired, the one thing you might want to understand is the amount of power that is going into those commercial devices. You're not talkign about a blinking dog collar here it's not as simple as you seem to think it is. You're talking about something meant to be used by fire or police professionals to identify their vehicles at great distances, not necessarily line of site.

If you're actually serious I would recommend you actually buy one of those bloated in price commercial units, take it apart identify every component and it's use in the circuit and then build a new circuit that can do the same thing, reliably day after day in automotive temperature conditions. You seem to think it's some sort of simple follow the schematic black box situation without knowing what is actually going on in the units you're talking about. Until then you're preaching to the same crowd that will give you no help, because it's not as stupid simple as you seem to think it is.

Its nice to see another officer here. I am a current one and have been working on a similar project. However, we are focusing on the controller end of it. Our current project will be more involved then just the light bar but maybe I can help you out. If you would like to stick with the lightbar itself, maybe we can provide the rest and combine them.

I'm not sure how to take your post though. Is it a general rant or did someone on here do something wrong?

As far as the light bar goes, what have you considered making the structure out of(metal, resin, plexi)? How about the lights themselves(leds, strobes)?

Thanks for the quick reply. The post was nothing personal, just frustration over hours of web searches looking for what is probably out there somewhere. Right now I'm looking at combining "off the shelf" parts / aluminum channel / LED pods from Chinese dealers on EBay / Bunches of Cat5 cabkle etc. One responder said to purchase one of the "big guy" bars and reverse engineer it, but I wouldn't know a resistor from a micro-chip (not really !) and thats more than I want to put into this project. I did locate a guy ( search "Chang Chung leds on Google" that looks to be a reliable controller/flasher but he's in Venezula and doesn't seem to have much business sense. I'm primarily looking for a flasher controller??? and working with the LED pods I've already purchased. My main interest is the "moth to flame" accidents involving cruisers on the road. I want to develop some type of rear facing warning system to reduce those situations. ..........Chief Jenkinson

Apology in order

My apologies are in order for those of you who took my post the wrong way. As I've responded, it came from frustration over what I think should be an easy fix. I've spent hours/months searching for the "holy grail" of flashers / controllers / circuits for a rear facing light warning system for police cruisers or other emergency vehicles. Those of you not familiar with the term "moth to a flame" is police jargon for the many incidents/accidents that occurr on heavily traveled roads at an emergency scene. Impaired drivers (drunk, asleep, drugs, whatever) are drawn to the flashing red/blue lights on emergency vehicles and drive right into the scene. The flashing lights are a magnet. I'm thinking of an add-on system using probably amber lights with a multi flash SLOW dwell. Amber seems to be the best color from studies I've seen and drivers react to it in a diff way.The slow dwell (lights staying on longer) is the way to go (my opinion). High powered red/blue flashes can impair a driver. White gets little response...............So anyway, thats what I'm looking for. I don't know from pics, and microprocessors, but I can read a schematic. I can solder part A to part B but thats the extent of my electroic knowledge. I guess its too much to hope for...............Chief Jenkinson

One problem you'll find is locating a suitable housing for it all. I researched this for our Rescue Squad, making the light flash is easy, locating a suitable housing is another story. It has to be weatherproof and rugged enough to withstand the ice,snow,tree branches and everything it'll be hit by. The best bet is to bite the bullet and get a commercial unit.

Perhaps you could give thought to a diversionary scheme: Design a portable, stand-apart light bar on tripod that could be placed away from the vehicle, yet still be seen by oncoming traffic.

Hopefully, the drunks and dopies will just follow the "flame" and drive into the light bar. It would be a bonus if the officer could set it up on the edge of a cliff.

Just kidding..... mostly.

Actually AllVol, I kind of like that idea, not necessarily for making the light bar remote but for raising it up so traffic can see it at a distance. More than once in heavy traffic (from the accident of course) I've been surprised by bar lights less than 50 feet away because of other cars.

retired, try to take things one step at a time. You'll need two completely different systems, the flasher unit itself which can be very basic and is almost trivial, the other is the actual light bar itself, the power LED controller which is the expensive part. As far as making LED's blink all you need to do is put them in banks using MOSFETS as switches to control which one is on or off. If you think you can get to the point of a light bar that has light output sufficient to meet your needs at a price that you're willing to accept them the thing that turns them on and off isn't so complicated.

Hi Chief,

I'm not familiar with US legal procedures concerning police light bars. (mechanical part, domes and fixation to a car).

May be you should invest a bit of time finding out which movie studio has leftovers of those devices used to produce movies. (They must have many of them according to some movies where up to 50 cop cars crash. )

Having those parts (or get the source for them) wil certainly be a good start.

Boncuk

I formerly worked for a contract electronics assembly house where we (for a time) built products for Code 3.

The LED systems I saw were built using high output Luxeon-type LEDs. A PIC processor was usually at the heart of the control electronics and the LEDs were driven using MOSFET drivers.

I don't think there was anything there that couldn't be accomplished with a 555/4017/MOSFET driver circuit. They used the PIC's so that they could have several switch-selectable flash patterns.

retiredlawman said:

I'm a retired police chief with over 35 years service to you guys.

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You've been here supporting us for 35 years? GLOAT, GLOAT! I trust you won public support in your locale better than you have done in this forum.

You comment about emergency lightbars being overpriced, but look at your other police gear. I'm sure you didn't trust your life on the streets by carrying a Tarus handgun. You probably had a Glock, Sig, Colt, or Beretta. I'm sure your flashlight was a MagLite or a SureFire and not a Ray-o-vac or Eveready! I'm sure your ammunition was name brand and not some substandard brand. Need I cite more examples to get you to understand that products from Whelen, Federal, etc. are the equavilents to the high-reliability brands tested and proven to support daily law enforcement/emergency services activities?

HiTech, I am with you on the "you get what you pay for" idea. However, I think the idea here is to build an affordable solution for individual officers/firefighters that are looking to equip their own vehicles on their own dime. There are also others such as storm chasers, private security firms, and just plain people who want to put lights on their cars that don't want to spend the $1200 for a brand name lightbar. Don't get me wrong though, I do agree with you.

Chief, have you already had quotes on LED modules? What type/wattage LEDS are you looking at? Right now, we are either going to use arrays of lower power LEDs or go with fewer 1w LEDs.

GatorGnet..........You hit the nail on the head. I was going to respond to "HiTech"s post but I didn't want to start a war. I'm corresponding with several guys on the forum so if you've seen this response, my apologies............I think "jbeng" has what I'm envisioning. All I have to do is figure out how to connect a PIC (and program) to a MOFSET to the last LED. Kinda wish I was into electronics instead of mechanical. Gimme a hammer and nail or a nut and bolt anytime !

In general, what I’m considering is an “arrow-stick” type light. I’m talking about an add on system that would attach to the roof or to the existing light bar. The stick would have fold out arms approx 2 feet beyond the width of the vehicle. Aluminum channel. At each end a large arrowhead. LED pods would flash in order, one at a time from the non-arrowhead end to the arrowhead. Directional from right to left or left to right and center out to each end. Pause, all lights on-bright, slow decrease in brightness to off, repeats. I think long dwell is an answer to the high-speed flash seen on other “sticks”. At freeway speed, they’re too fast to give direction. Most don’t have a large arrowhead to show direction. I think that part is necessary. And if I can deveop a flasher with patterns, maybe they could be incorporated into the light. (Flash, multi-flash, strobe, alternate, etc)
I’ve thought about signage: “go left”, “go right”, “stop”, “ crash ahead”, etc; but that may be too much. Don’t want them to really “read”, just follow directions (at 65MPH +).
I’ve enclosed three links (or tried to). The YouTube link is for a flasher built by a guy in Venezuela. He sold the flasher on Ebay for a while but ran into problems with PayPal. He started at $15, then 18, then 25, and the last I’ve heard from him is 28. I tried to set up a deal with him to purchase in multiples, but he can’t provide. He sold a few but I think it was just a hobby. Takes him forever to respond. But he does have that SLOW dwell!!
The other links are for LED pods that I’ve purchased on Ebay. These are Chinese dealers and they’re selling retail. (I did get a little reduced cost, but so far, I can’t find the manufacturer) They have all manner of “strobe” LED lights. I’ve got both on hand. They are not Cree or Luxeon but are at least as bright as Cadillac brake lights and I think 2nd generation. I think the high-powered LEDs may overpower the existing warning lights. Some of them are almost too bright. And with Cree or Luxeon, I have to design drivers and heat sinks and pods and seals, etc. THESE are NOT waterproof no matter what they say, but they are pods with attachments.
A good (in my opinion) supplier of Cree, etc, is DealExtreme.com if I have to go that way.

ChangChung flasher: YouTube - New Strobe Led Flasher ChangchungLeds For Sale send a message

22LED pod: **broken link removed**

3LED pod: **broken link removed**
(My links didn't attach..........I'm no computer whiz !!)

Just a thought, but after 35 years you would have retired with quite a sizable golden handshake. Now this product you are interested in designing will have a high sale price (probably a few grand each!) to lucrative government markets for emergency vehicles etc.

Why the penny pinching? Why not just throw a few grand at one of the pro or semi-pro electrical engineers here and get them to do all the tricky electronic design for you and just hand it to you. Then with the product developed quicker and more professionally you could concentrate on the marketing side, using your 35 year "cred" and contacts to get some orders and contracts etc.

Just a thought.

I think it would be better to use three 3W LEDs in series with a suitable resistor or constant current source - that should be pretty bright even in full daylight.

There are plenty of patern generator circuits in the thread Harvey linked to in his first reply to this thread.

I think Cheifs idea is to keep it under a few hundred. If that high. The lightbar we are working on right now is targeted for the $200-$300 range.

Hero999 said:

I think it would be better to use three 3W LEDs in series with a suitable resistor or constant current source - that should be pretty bright even in full daylight.

There are plenty of patern generator circuits in the thread Harvey linked to in his first reply to this thread.

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I agree with you on that one. We are testing both arrays of 20ma leds and 3-4 1w or 3w leds. The problem with the 1w leds are their price. Most places want $2-$4 for each led.

It might be cheaper to by a few 3W LEDs rather than a hundred or so 5mm LEDs: he'll need to investigate which is more cost effective.

Sorry, work 2 jobs 7 days a week to pay the bills. Walk a mile.............The idea is to keep the cost to the unpaid volunteer at under $50 each.....DJ