# strobe

#### 79bronco

Joined Oct 28, 2007
11
Ok guys i need some help. I dont know where to start on this project.

I want to use 10 10,000mcd LEDs and have two sets of 5. I want one set to flash 4 times then switch to the other set and flash 4 times...

It will be ran in a car so around 13.5 - 14.5 volts. and about 12 volts when the cars off. so maybe throw a voltage regulator in there to keep the brightness constant...

any body got a schematic?

#### hgmjr

Joined Jan 28, 2005
9,027
Have you selected the LEDs you intend to use? If so, can you supply the part number and manufacturer's name?

hgmjr

#### 79bronco

Joined Oct 28, 2007
11
Have you selected the LEDs you intend to use? If so, can you supply the part number and manufacturer's name?

hgmjr
Linrose B4304H95

#### lightingman

Joined Apr 19, 2007
374
Hi, I would do it with a PIC12F675, or other small PIC microcontroler, a couple of small MOSFET's, and a few other components.The program code for this is so simple.Daniel.

#### hgmjr

Joined Jan 28, 2005
9,027
lightingman has an interesting suggestion. Are you comfortable with programming and microcontrollers?

hgmjr

#### 79bronco

Joined Oct 28, 2007
11
lightingman has an interesting suggestion. Are you comfortable with programming and microcontrollers?

hgmjr
never done it before but there is a first for everything i guess...

#### hgmjr

Joined Jan 28, 2005
9,027
What is your estimated budget for this project?

hgmjr

#### 79bronco

Joined Oct 28, 2007
11
What is your estimated budget for this project?

hgmjr
This actually isn't for me...its for a friend but i don't think he cares much about the cost...so maybe post a cheap way and an expensive way?

#### hgmjr

Joined Jan 28, 2005
9,027
This actually isn't for me...its for a friend but i don't think he cares much about the cost...so maybe post a cheap way and an expensive way?
OK. That sounds like a plan.

I will let lightingman provide a microcontroller based solution and I will see if I can put together a less expensive alternative.

The advantage to lightingman's approach is the flexibility to change the flash pattern in literally dozens of ways. The only thing needed is to change the program running on the microcontroller. The up front cost of acquiring the development board is the main downside to the microcontroller approach. Of course you only have to buy the tools once and you can tackle all of your future projects with microcontrollers.

With the less expensive method, I will set the number of flashes to be 4 as required. The primary flexibility that will be provided is the flash rate will be adjustable.

Do you have a timeframe in which the project must be completed?

hgmjr

#### 79bronco

Joined Oct 28, 2007
11
OK. That sounds like a plan.

I will let lightingman provide a microcontroller based solution and I will see if I can put together a less expensive alternative.

The advantage to lightingman's approach is the flexibility to change the flash pattern in literally dozens of ways. The only thing needed is to change the program running on the microcontroller. The up front cost of acquiring the development board is the main downside to the microcontroller approach. Of course you only have to buy the tools once and you can tackle all of your future projects with microcontrollers.

With the less expensive method, I will set the number of flashes to be 4 as required. The primary flexibility that will be provided is the flash rate will be adjustable.

Do you have a timeframe in which the project must be completed?

hgmjr
Well as soon as possible but i dont need any one to rush into it....its not really urgent...

and thanks for the help guys!

#### lightingman

Joined Apr 19, 2007
374
Hello,Yes indeed... I would be happy to help you here...If you are happy with building this, I could program a PIC12F675 for you....It is only an 8 pin DIL device, and only cost about £1.00.....So, I get the idea about what you need, but will you need some sort of speed control on it...If you could give me as much info as possible, that would be great....Here comes the BUT... I am very busy until next week, so I could not get it to you until about the end of next week...P.M. me your address, and I will sort it out....Daniel.

#### drew23

Joined Oct 30, 2007
1
I am new here and I too am interested in a microcontroller setup. I am on a volunteer fire dept. and am in the process of installing warning lights in my vehicle. I would like info on an external flasher with multiple patterns. Hopefully I can follow this post and learn.
Thanks

#### lightingman

Joined Apr 19, 2007
374
That's fair enough....When I get the info from 79bronco, I will do the business and post all the schematics and program details (if he does not mind)...Daniel.

#### 79bronco

Joined Oct 28, 2007
11
A speed control would be nice...It just needs to control the 10 LEDs (2 sets of 5) 4 flash from one set then 4 flash from the other set. Like i said a speed control for it would be nice but not needed. Time is no issue. If theres any info that you need just let me know...

Thanks!

#### 79bronco

Joined Oct 28, 2007
11
I am new here and I too am interested in a microcontroller setup. I am on a volunteer fire dept. and am in the process of installing warning lights in my vehicle. I would like info on an external flasher with multiple patterns. Hopefully I can follow this post and learn.
Thanks
Multiple flash patterns would be sweet...but also not needed...

#### lightingman

Joined Apr 19, 2007
374
O.K,Leave it with me for a week or so, and I will do it for you...Daniel.

#### hgmjr

Joined Jan 28, 2005
9,027
A speed control would be nice...It just needs to control the 10 LEDs (2 sets of 5) 4 flash from one set then 4 flash from the other set. Like i said a speed control for it would be nice but not needed. Time is no issue. If theres any info that you need just let me know...

Thanks!
Greetings 79bronco,

I am tackling the design of a non-microcontroller version of the flasher. I have made a lot of progress over the last couple of days and I am now to the point of setting the component values.

I need a few details to make sure that I have the flashing sequence clearly understood.

When you say "4 flash from one set" then "4 flash from the other set", are you expecting the 5 LEDs in the first set to all flash simultaneously a total of 4 times and then the 5 LEDs in the second set to flash a total of 4 times simultaneously. (See inset below)

I realize that you are wanting the pattern to repeat as long as power is applied to the circuit.

Rich (BB code):
1. All 5 LEDs in set #1 turn on then off (first flash)
2. All 5 LEDs in set #1 turn on then off (second flash)
3. All 5 LEDs in set #1 turn on then off (third flash)
4. All 5 LEDs in set #1 turn on then off (fourth flash)
then
5. All 5 LEDs in set #2 turn on then off (first flash)
6. All 5 LEDs in set #2 turn on then off (second flash)
7. All 5 LEDs in set #2 turn on then off (third flash)
8. All 5 LEDs in set #2 turn on then off (fourth flash)
9. return to step 1 and repeat
The other detail I need to know is at what rate did you want the set of 5 LEDs to flash? (for example, set the flash rate so that is takes one second to flash 4 times on the first set then one second to flash 4 times on the second set, then repeat the pattern)

hgmjr

#### 79bronco

Joined Oct 28, 2007
11
all 5 come on at once. then the next 5. i want it to be pretty fast...but not so fast that you wont be able to notice that its flashing...so 4 flash's in 1 second would prob be about right....

#### hgmjr

Joined Jan 28, 2005
9,027
all 5 come on at once. then the next 5. i want it to be pretty fast...but not so fast that you wont be able to notice that its flashing...so 4 flash's in 1 second would prob be about right....
That's just what I needed to know. Like lightingman, I plan to give some measure of adjustment.

hgmjr