Well I'm trying to build some electronically actuated things to help me using the car daily. First thing I'm trying to change is my flasher - it's just too slow. It takes like a second from hitting the lever till the lights start blinking. What I'm trying to do here is to get a microcontroller of some sort which are usually running at 3.3V or 5V - I can get that off 12V with a voltage regulator, no problem. However I'm thinking with what should I drive the bulbs. Would a MOSFET do the trick or are voltage drops in those too big and the bulbs would wear out faster? And yeah I know you can buy electronic flashers but I'm trying to do one myself.

Thanks in advance for any replies.

Cebix,

IIRC, that is a symptom of a heavy duty flasher....and using a heavy duty flasher with standard bulbs (therefore load) will take longer to heat up the bimetallic element resulting in slower start and slower blink rate. I would change out the flasher and check for clean connections before I did anything else! Oh, and verify you have full voltage, too, since that would also cause those symptoms.

Good luck,
Larry

Yeah that can be the case but I have several flashers and just don't want to play around with them anymore. Also building my own I'm hoping to start more and more advanced stuff but I thought this would be an easy start. So I just want to get rid of it altogether and have something more reliable and gain experience to build more stuff.

But I think relays are too unreliable and I would like to get some opinions on MOSFETS or what would be better. Also what I will be trying to make is a simpler headlight motor circuit so I can get rid of those relays and mechanical switches and just run them off a microcontroller.

[This message has been edited by cebix (edited 02-15-2013).]

OK, I understand what you want to do....this might give you some ideas and a head start: http://e31wiki.org/wiki/One..._module_(PN_version) or this: http://e31wiki.org/wiki/One...l_module_(N_version)

Larry

Hey thanks man that's some nice stuff I've never heard about. Gonna have to look into that.

EDIT: Yeah that's exactly what I was thinking about, never knew it was done before. Thanks again for the links.

[This message has been edited by cebix (edited 02-15-2013).]

1. Make sure all bulbs are working and you dont have a burned out one
2. Check and make sure you are not running some kind of wrong blinker breaker
3. If all that checks out, install 2 resisters, 1 on each bank between the power side and ground. Your average bulb is around 6 ohms (I think, you should check) so find something around there. They sell them on ebay and other places as 'led blinker fixers', they need to be somewhat high wattage. at 6 ohms and 14 volts, thats around 35 watts.

but thats all mostly just fun to talk about, you just have something wrong. If your thinking about building a voltage regulator to drive a microcotroller, which will be trigged by 2 inputs that would also have to be drven through a voltage divider, and then using that whole thing to drive a set of mosfets to drive lightbulbs...you should be able to figure out the blinkers on a fiero.

Yeah I think the flasher is just the wrong type like heavy-duty or whatever (it works the same way on every car I tried that still uses those old ones) but I just can't get any good ones here in Poland and nobody knows nothing about them since they are long gone in cars so I decided not to play with them anymore.

[This message has been edited by cebix (edited 02-15-2013).]

In the type of slow speed applications like you are looking at, a relay or a power darlington would probably be better than a mosfet.

A typical power mos has a vgturnon of 4V (N channel), and your typical 5V miscroprocessor only just exceeds that. You can run a p channel with resistor biasing, but they have increased channel resistance. This is not huge in your application, but simpler is better. With light bulb in rush, if it's just a turn on turn off deal relays are so simple. No biasing, no gate drive reqauirements...


Chay

Yeah in the links posted by imacflier are a few circuits. The simpler ones use just one mosfet and the more complex use the darlington scheme with one transistor driving the mosfet so it will be gated at full 12V.

see www.fiero.nl/forum/Archives...120111-2-104975.html
or Blazer brand at many part stores

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

They're unavailable here and the electronic ones that are sold here are pretty expensive and hard to find (most are three or four poles, not two) but thanks for the link.

All right, a quick question because I won't be around my car for some time to check myself - how much amps the turn bulbs draw when flashing in a Fiero? Or in other words how much amps flow through the flasher when a turn signal is on?

I figure on a notchie we have 3 two-filament bulbs in the rear and that high filament is 21W am I correct? On the front we have the same situation but only 1 bulb, two side bulbs but small I guess 5W? And the instrument cluster bulb also 5W. So that gives us 99W and divide that by 12.5 (I guess the lowest possible healthy battery voltage when engine shut off) we get roughly 8 amps. 8 amps in theory but what's the real current consumption?

Also what happens when a bulb goes out? Does the current drop or raise and by how much? I guess they just act like a wire would be broken so the resistance is infinite and the current goes down by a little depending on the wattage of the bulb that died? Is that correct?

[This message has been edited by cebix (edited 04-02-2013).]