# LED Emergency Vehicle Flasher

#### emtffkev

Joined Sep 17, 2007
5
Ok guys (and gals?) I am by far a rookie in the hobby electronics world so forgive any hints of ignorance I might throw out there.

I am a paramedic/firefighter and I've always toyed witht he idea of making some high output LED strobe/flashers to put on my vehicle. The ones out there are very expensive and very overpriced and I'd like to save a couple dollars and learn some along the way.

I've got two types of led's I'd like to try and make, the first being just a high output flasher that flashes in a pulse type pattern.

* = flash
Something like this:
*** *** ***
3 quick flashes and then a pause

the other type I'd like to be able to pull off is just a flasher but it would be for the headlamps. I'd want to have two of these and have them alternate back and forth.

R L R L R L R L

Something like that.....maybe even have the ability to change it if I want to to:

RR LL RR LL RR LL

There is a commercially made on that does similar to what I'd like for the second one, you can take a peek at the design at this ebay link...I don't think the guy has a regular website. This is the link.

I'd be glad to give anything I may have left out. I'm not asking for this just to be handed to me, I like to learn and I'll do some brain work to figure it out, I just don't know what/where to start.

#### HarveyH42

Joined Jul 22, 2007
426
You should consider a microcontroller, a 60 cent chip could do all those patterns, and it's a very simple program (my third program I did when I just got started with AVR). Actually most microcontroller tutorials for beginners, start you of with simply flashing an LED. So you wouldn't have to get into it all that deep to get exactly what you want. The chip programmer can be made very cheap and easy with a parallel cable and a few descrete parts. The software for the AVR series is free, believe PIC has a free trial version, which should be good enough. It's really not as bad as it sounds.

I've seen this with logic chips on another forum with logic chips, several times, it's a mess, and more complicated then getting started with a microcontroller. Here's a link to one such thread, use the search function there, been several others...
http://www.electro-tech-online.com/...flasher-strobe-circuit.html?highlight=flasher

#### emtffkev

Joined Sep 17, 2007
5
Thanks for the input, I had considered using a PIC, but I am just about as lost with that as I am with a regular circuit. I'd love to give the pic a whirl, do you have any articles/tutorials i can check out. Any personal advice? Thanks a mil.

While I'm at it, do you have any info about a pic programmer?

#### niftydog

Joined Jun 13, 2007
95
Suggest you look into PICAXEs instead. They're super easy to learn, the software is free (last I looked) and easy, and the programmers are simple and cheap.

Joined Jan 10, 2006
614
Try the real cheap, real easy to program Picaxe 08

#### HarveyH42

Joined Jul 22, 2007
426
Have to agree that PIC would probably be your best choice, so much on the web. I'll grab the link to one very good PIC tutorial site next time I'm on the other forum site. I use AVR, but those tutorials are very clear and helpful.

Most first micro projects are simply to flash an LED, so it won't take much thought or trouble to expand it a little to get the effects you want. Sorry to push the micro so much, but it will be much easier to duplicate once you got one working. You co-workers will be wanting them too, so this will save you considerable time and hassles in the long run, plus you cut parts cost to just a fraction. PICs seem a little more expensive then the AVR chips I've been using, but wouldn't think more then a couple of dollars.

The output of a microcontroller is about 20-25 mA, so can handle an LED alone, the headlights will need some help, like a transistor or a FET.

Try searchin 'PIC Tutorial' on the web, and see what you find. I'll post that one link later today...
I just searched the fragment I remembered, and got it...

http://www.winpicprog.co.uk/
Scroll down until you find the tutorial link.

#### emtffkev

Joined Sep 17, 2007
5
Thanks guys for the great direction. I'm gonna do some research and stuff, and I actually have some pics at the house I got on a free sample.

The headlight thing is actually going to be LED "strobes" that are inserted into the headlight housing, not flashing the actual headlight itself. And you have that right about everyone wanting one, already have 4 guys that want to see what I come up with.

Joined Jan 10, 2006
614
the PICAXE 8 costs between $2 -$5 depending where you are, and requires only a 5 volts supply, a few resistors, a serial cable, and free software to program it in BASIC.
Google it. Revolution Education in the UK does em, and supports em... but they are available from everywhere.

#### HarveyH42

Joined Jul 22, 2007
426
I'd don't think you will have any regrets going in this direction. You should have absolutely no problem with the code, plenty of people in the forums to help, and it would literally only take minutes to write. Here's a link to another post. It has a bunch of links to PIC stuff for beginners, might be of some help.

http://www.electro-tech-online.com/...2-programmers-simulators-debuggers-oh-my.html

My first origional AVR project was an IR proximity detector, that was to police-flash (red and blue) and a siren. The siren wasn't that loud, and it kind of drained the batteries quickly. I got a range of 18-24", and every thing fits on a 1.5 inch square PCB. Took less then a week from concept to completion. Hadn't done any programming in about 15 years. It really is that simple to get started with.

PIC seems to be the number one most popular among hobbists and college students (not sure why). I chose AVR because it's instruction set was more familiar to what I worked with years ago, so would have to start all over, or learn a high level language like 'C' or BASIC. I have to do a lot of searching to find similar projects in assembly, but often find exactly what I'm looking for using a PIC. You won't have any trouble find complete projects to build after your flashing lights, if you are interested in doing more.

#### emtffkev

Joined Sep 17, 2007
5
Ok, why don't I start at ground one.

I've decided to go with the PIC route.

I guess step one in my little adventure is learning how to build a good versatile pic programmer.

Does anyone have schematics, links, know how, or anything else of a pic programmer that:

1. Can run by either windows or linux.
2. Not too concerned about what connection it takes, might be nice to have one that is parallel for ease of going from one computer to the other.
3. Can program different types of PIC's and has expandability if need be.

I guess my only other requirement is that I build it, I like making things into learning experiences and think that any practice I can get with making circuits is good practice.

Joined Jan 10, 2006
614
PIC's or PICAXE's...... the PIC needs more supporting hardware, and it's hard to find free software.
The PICAXE is not as powerfull, but needs only a connection to a the COM port of a PC with a few resistors and some voltage regulation, and the software is free.

#### emtffkev

Joined Sep 17, 2007
5
Well I'm not really sure between the PIC or PICAXE. I do have some PIC's that I got for free on a free sample. It sounds easier to get going with the PICAXE, but am I going to run into limitations?

Joined Jan 10, 2006
614
Limitations of PICAXEs are more to do with speed, and lack of more complex programming and functions.
A real simple program like the one below, takes a few minutes to write and outputs 3 x 100mS High transitions from pin 1 (with 500mS pauses) and a break of 1 second before repeating.

start: for b1 = 1 to 3
pulsout 1,10000
pause 50000
next b1
repeat: wait 1
goto start

The PICAXE allows you to load the program, try it, and reload the program with changes until you are satisfied with the operation

Joined Jan 10, 2006
614
And this BASIC program should do all 3 patterns.... checking each sequence for a high input (from a push button switch) on pin 3 of the micro. Pushing the button at the start of a flash sequence moves the pattern on to the next routine. Pin 1 goes to whatever controls the first LED's..(or drives a single LED directly), and pin 2 the second.
There are lots of ways to do the same thing, some people would use Subroutines..(gosub/return), and some might use better input detection so that the push button can be sensed at any point. This is only a simple example.
(NB ignore the dots, only there as can't use tab bar)

init:.....pulsout 1, 100
..........pulsout 2, 100
flash:...for b1 = 1 to 3
..........pulsout 1, 10000
..........pause 50000
..........next b1
..........wait 1
..........if pin3 = 0 then goto flash
alt:......pulsout 1, 10000
..........pause 50000
..........pulsout 2, 10000
..........pause 50000
..........if pin3 = 0 then goto alt
rrll:......for b1 = 1 to 2
..........pulsout 1, 10000
..........pause 50000
..........next b1
..........for b1 = 1 to 2
..........pulsout 2, 10000
..........pause 50000
..........next b1
..........if pin3 = 0 then goto rrll
..........goto flash