Build Your Own LED Turn Signals!

[likearock111]

Nice! Also, you don't even need to do the last step (wiring the switches in) in order to test the device to make sure it's working properly. Just hook the positive leads of the light and the CD4047BE directly to +12V, attach GND (0V), and let 'er go!

 

[eltatertoto]

cant wait till mornin! lol. i fried my glue gun a long time agao. so i think ill use electrical tape for now. going to bed...

 

[eltatertoto]

rock, 1 last question. ill come back in to read this before i test it. with the laptop thingy, it has that tip thing with the hole in the middle, is inside positive or outside?

 

[eltatertoto]

well, i found my dad's old motorcycle battery, but i got stuck at thew switch part. im pretty much clueless. ill read those tuts again, and get back to ya.

 

[likearock111]

rock, 1 last question. ill come back in to read this before i test it. with the laptop thingy, it has that tip thing with the hole in the middle, is inside positive or outside?

Great question. I would guess that the inside is positive and the outside is negative, but you shouldn't take that as truth. I'd whip out the multimeter, put it in voltage-measuring mode, and check.

 

[eltatertoto]

thanks, but i found my dads old harley batt. ill use that to test. still looking at tuts.

 

[likearock111]

Does this help?

2 and 5 are the "throws". They go back and forth. In one position, the throws make connections with pins 1 & 4 (as shown), and in the other position, the throws make connections with pins 3 & 6 (this position is not shown in the diagram). The throws ALWAYS move TOGETHER. This fact is represented by the dotted line in the schematic.

Position A:
Pin 2 connected to pin 1
Pin 5 connected to pin 4

Position B:
Pin 2 connected to pin 3
Pin 5 connected to pin 6

 

[eltatertoto]

thanks for the schematic! , im hurring, cause i read u wanted to know if it worked. but i got 1 side done. out to do the other. gotta hurry tons of kids out and my bike it sittin there.

 

[eltatertoto]

i got i built....... but i had a little issue if ya will. read the description to know what im talking about. IF YOU ARE OFFENDED BY COARSE LANGUAGE PLEASE DO NOT WATCH that said heres the link.

http://www.youtube.com/watch?v=UGVeCx5R9Z0

 

[likearock111]

Now, that's a cryin shame. I feel for you - that's happened to me a couple times before.

Do you know what exact pins touched each other? I'm trying to rationalize how one of the Mosfets could have fried - they're capable of 10A of current, which should be much much more than you need for this. Is the CD4047BE still working? To test this, put the multimeter between pin 10 and ground, and see if the voltage still goes from 0V to 12V to 0V to 12V, etc.

I have to say, I'd actually suspect that you may be experiencing something called "Mosfet ringing" that can sometimes occur when you put two Mosfets in parallel (as we are doing in our circuit). Technical information on Mosfet ringing can be found here.

This has been known to, in rare cases, blow out parallel Mosfets. It hasn't been any problem with mine personally, but I used two completely different Mosfets than you did.

At any rate, if this IS the problem you're having, then it's an easy fix. All you need to do is solder a 5-ohm (NOT 5-kilo-ohm) resistor in between pin 10 of the CD4047BE and the gate pin (labeled with a "G") of each of the Mosfets. Adding these two resistors should completely eliminate the problem, if that's what's going on.

Actually, if you go back to my original post, I mentioned a couple of "optional resistors" that electrical engineers might include. These are the ones.

By the way, did you get the switches to control the lights properly? And also, were the Mosfets getting hot to the touch at all? If so, you may need a couple heat sinks, although I doubt it. I'd also go ahead and determine how much current each of your halogens is drawing, so that we can get a better picture of what might be the deal here.

Good luck!