LED Flasher/strobe Circuit

[ste1070]

Hi,

Need to construct a LED strobe type flasher unit which flashes 2 pairs of amber/yellow LED's. Ideally needs to run on either 2 x AA batts or 9v cell. Need to flash twice quickly on 1 pair then change to other pair and keep alternating similar to emergency vehicle type but to run a small battery.

Can somebody help me?

Thanking you in anticipation.

Steve

 

[Andy1845c]

If you search the forums for LED strobes, there have been a couple topics on this. Or handy dandy search feature isn't working at the moment though. The double flash will make it harder to do. I simple 555 timer can give you a single alternating flash.

 

[ste1070]

Thanks for quick response. Trouble is am an electrician and have limited electronic knowledge. Will double flash be big problem as need this really?

 

[Andy1845c]

https://www.electro-tech-online.com/threads/how-to-make-this.24824/?highlight=ways

Theres one of the topics I was thinking of. The last response might help you. If you dig around here, theres more I know. I just can't remember the titles.

 

[ste1070]

https://www.electro-tech-online.com/threads/how-to-make-this.24824/?highlight=ways

Theres one of the topics I was thinking of. The last response might help you. If you dig around here, theres more I know. I just can't remember the titles.

What components would I need for this and is a diagram available? Sorry to be a pain!

 

[audioguru]

There were a couple of discussions about blinking an LED twice then blinking another LED twice, for toy police cars.

A circuit used an oscillator driving a CD4017. The 1 and 3 outputs of the CD4017 had diodes to a transistor to blink the 1st LED, then outputs 5 and 7 had diodes to another transistor to blink the 2nd LED. then the 8th output of the CD4017 made it reset.

EDIT: The IC is a CD4017.

 

[jbeng]

The 1 and 3 outputs of the 555 had diodes...

You meant the CD4017, right?
JB

 

[RODALCO]

4017

Use a 4017 IC driven from a 555 IC or eq. to make it receive clock pulses.

Put on all 4017 outputs blocking diodes, set the light sequence with additional diodes after the blocking diodes, then drive the output transistors and led's as required.

 

[audioguru]

If you make the LED current really high then they will blink as brightly as strobes, maybe even with a bit of smoke. But only one time.

 

[AllVol]

Hi, ste1070

If you are interested, attached is a simple program using PICAXE that will do exactly what you desire. Programming a PICAXE is probably the simplest of all, using the free Program Editor and a simple three-wire RS232 cable.

After you are through programming, simply mount the 8-pin AXE007, two resistors and the two LEDs, plus three AAA cells into your model car and have fun!

See also: www.jrhackett.net

Hope this helps.

AllVol

Sorry, the attachment would not download. I've never had that problem before.

 

[AllVol]

Let me try that attachment again.

 

[Roff]

If you want a solution that doesn't involve a microcontroller, here's a schematic of what Audioguru described. You can tweak pulse widths and LED currents to suit your needs.

 

[AllVol]

Not that I'm pushing PICs, although I am rapidly becoming attached to them, just compare the attached schematic with that of Little Brave and Nanuk of the North.

1. Fewer components (count 'em)
2. Less construction time (even if you count programming time)
3. Less chance for error
4. Possibly longer battery life
5. Even a dummy like me can do this

AllVol

 

[cadstarsucks]

Not that I'm pushing PICs, although I am rapidly becoming attached to them, just compare the attached schematic with that of Little Brave and Nanuk of the North.

1. Fewer components (count 'em)
2. Less construction time (even if you count programming time)
3. Less chance for error
4. Possibly longer battery life
5. Even a dummy like me can do this

AllVol

Could have fooled me. A 74AC14, A74AC161, 3 resistors, and a capacitor will do it if you do not care about the pause between the color changes and can supply 50mA to the LEDs.

D.

 

[Roff]

Could have fooled me. A 74AC14, A74AC161, 3 resistors, and a capacitor will do it if you do not care about the pause between the color changes and can supply 50mA to the LEDs.

D.

That's still more parts than the microcontroller solution. Why don't you step up and provide a schematic, anyway. Talk is cheap.

 

[cadstarsucks]

Anti-PICs and schematics

That's still more parts than the microcontroller solution. Why don't you step up and provide a schematic, anyway. Talk is cheap.

The PIC costs more and does not provide the current for an impressive flash. Be that as it may, perhaps I will when I get home from work!

D.

 

[Roff]

The 161 is a 4-bit binary counter. My question is how are you going to get two flashes on one output, then two on another, without a decoder?

 

[cadstarsucks]

That's still more parts than the microcontroller solution. Why don't you step up and provide a schematic, anyway. Talk is cheap.

Oh fine! Here, I did it on my lunch hour...

 

[cadstarsucks]

The 161 is a 4-bit binary counter. My question is how are you going to get two flashes on one output, then two on another, without a decoder?

using the LEDs as their own diode or gate

 

[cadstarsucks]

That's still more parts than the microcontroller solution. Why don't you step up and provide a schematic, anyway. Talk is cheap.

hmmm it did not link the upload...