LED + wig-wag

I am trying to make a circuit with possible 4 LED's set up in a row like 1 2 3 4. I would like LED 1 and 4 in an alternating strobe pattern much like a police car's lights while LED 2 and 3 wig-wag. LED 1 and 4 must also flash twice before switching. Power = 9 volt battery

(using Red and Blue LED's)

Can someone help? Parts list + schematic much appreciated

I have a Wig-Wag circuit already but is is not for LED's

I have been using other LED's flashing circuits and Wig-wag circuits. I have Video and pictures of what I am attempting. If you wish to see, Please ask

Any ideas about how you want to do this? I'm not going to research the project for you, and I'm certainly not going to make you a parts list and assembly instructions, but if you need help with a specific part of it I'll try my best.

Ideas? You mean what parts, power, resistors etc etc I plan on using?? Well, sorta.

Well then discuss your ideas. Where will you start? How bright do the LEDs need to be? How accurate does the flashing need to be? What do you plan to use to control the flashing? You've given me nothing so far.

Ah, well I was planing on using a 555 IC for the wig-wag part. Brightness, I would say maybe as bright as a LED flashlight. The strobe LED's same brightness and I am unsure how to get the LL RR LL RR LL RR LL RR LRLRLR pattern.

I think a State Machine would be the best way to tackle this kind of problem. Can I ask, what is "wig-wag"?

Brian

have you considered using a microcontroller? This could easily be done with a simple micro, many micros have pleanty of power to drive fairly bright LEDs. The big advantage of using a micro is the ease of getting the pattern of flashing and timing that you want. It will also be more accurate than a 555 timer. I'm not sure how to do the the LL RR LL RR pattern using ICs, but I'm sure it can be done. Perhaps someone else here can offer a suggestion?

If he had experience with Microcontrollers then I'm guessing he wouldn't need to be asking the question in the first place.

Brian

slosjo said:

LL RR LL RR pattern using ICs, but I'm sure it can be done. Perhaps someone else here can offer a suggestion?

Click to expand...

I think this could be done via a state machine. First I need to know what wig-wag is and how this ties into the problem as a whole, then I think I'm gonna have a crack at it!

Brian

Ok I started looking into a State Machine solution and then I thought hang on... why the need to dive in with such a complex solution? Just use a counter and some output forming logic.

I've drawn a truth table which I think will satisfy your LL RR LL RR pattern, please see attached. Basically you'll want a 3-bit counter and some output forming logic to create your required outputs. L (Left) is only logic 1 on two occasions, and R (Right) is only 1 on two occasions - so the output forming logic will be relatively simple.

Are you able to proceed from this point or do you need help with the output forming logic?

PS: The attachment isn't really a zip, it's a Word document. I had to name it a zip because it was over 19KB and the server wouldn't accept it. Rename it back to a .doc your end!

Brian

Brian, a wig-wag is 2 (or more) lights flashing in a pattern like this LR LR LR LR with equal amount of on and off time. The first 5 seconds of the video is a wig-wag but they aren't LED's
https://youtube.com/watch?v=z05Mbyb9K0U

Check my first PIC tutorial, it shows how to flash 8 LED's in any pattern you like.

Hmmmm. I think my solution for the LL RR LL RR LL will produce the pattern you want, but not the effect. I'm assuming you want the LL RR LL RR LL pattern to have a strobing effect - the solution I showed you earlier will not provide that.

A strobing effect is even easier though - you can run it all off two tripple-5 timers (or five-five-five timers if your name is AudioGuru). You'll want one 555 for the strobe, and one for the count. If you then gate the strobe and the count with an AND gate, and connect your LED to the output of the AND gate, you'll get an effect where the LED will strobe for the amount of time that the "count" 555 is high. If you invert the "count" 555's output to feed the opposite LED, then you'll get an effect where the red LED will strobe for as long as the "count" 555 is high, and the blue LED will strobe for the amount of time that the "count" 555 is low.
Your Wig-Wag LEDs can be taken directly from the "count" 555 output and the NOT "count" 555 output.

Is this clear so far? I can draw it out in a diagram if it's not. The only problem with this solution is that it's not possible to have a 50/50 mark space ratio with a 555, unless you add a bit of clever circuitry.

Let me know if this solution sounds reasonable to you.

Brian

Could you supply a diagram if you wouldn't mind

Hi Asunachan,

The first part is the strobe, the second part is the "wig-wag".
You can use any P-channel mosfet you can get your hands on, like
IRF9510 to IRF9513; IRF9520 to IRF9523; IRF9530 to IRF9533;
IRF9620 to IRF9623; IRF9630 to IRF9633, . . . or even BS250's.
The 68 hm: current limiting resistor was selected for use with
three blue leds with a forward voltage drop of 3,3 volt.
Do you need a siren too ?

on1aag.

Well, On1aag's solution seems a little more elegant than mine, so I would suggest you go with that one!

Brian

on1aag said:

Hi Asunachan,

Do you need a siren too ?

on1aag.

Click to expand...

....Did you say siren!? Oh yes that would be wonderful! Thank you!! My attempts at locating something like the real thing has been difficult. The closest find was a MP3 player with a recorded siren

So the first diagram is the Strobe LED's and the second is of the wig-wag ones right?

A strobe light doesn't just turn on then turn off. It flashes for a very short time. A CD4060 has a built-in oscillator and its counter can drive the gates to make short duration flashes. The gates could be diodes but must have more inputs.

Sorry if this sounds mean but, ausioguru, I know what a strobe is. 1) I believe they are used in most camera's for the flash. 2) I have seen them on police cars, ambulance's, and fire trucks. 3) I have 2 full sized light bars with strobes in my basement and have used both of them. I am trying to scale it down to R/C car size using LEDs

I built a circuit to do exactly this: strobe LEDS in an LL RR pattern on an RC car. However, I designed my circuit to run on +5VDC, and used a voltage regulator to drop the voltage down from a 9V battery. Basically, I did this because I have a lot of old 9V that run at about 7.5V that I wanted to use (from an old smoke detector). If you want to change the circuit to run on 9V, you're going to have to play around with the resistor and capacitor values to get the timing right, and be sure to adjust the current limiting resistors for your LEDS...

Here's the schematic. I pulled the parts from old electronics, and they seemed to work. No ICs, only resistors, transistors, capacitors, and diodes. You can probably substitute any variety of NPN and PNP resistors, provided they can handle the amount of current you're looking to drive. Mine did fine running 6 LEDs total.

Also, please note that D1 and D2 ended up being LEDS. For some reason, it wouldn't work with small-signal diodes (although it may be because I used salvaged parts). I'm currently working on a protoboard layout to build a more permanent version of this circuit.

Good luck. Let us know how it turns out.

jptrsn.