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Blinking third break light

B

Bryan

Jan 1, 1970
0
Hi.
My wife has me to build her a circuit that will make the third brake light
blink light her friends (lucky me). Since I am rather new to electronics,
can anyone offer any PCP designs or schematics? Thanks for any help!!

Bryan
 
T

Terry

Jan 1, 1970
0
Bryan said:
Hi.
My wife has me to build her a circuit that will make the third brake light
blink light her friends (lucky me). Since I am rather new to electronics,
can anyone offer any PCP designs or schematics? Thanks for any help!!

Bryan
Is that legal?
BTW yesterday driving behind car with driver side rear brake light out of
action realized that's another advantage of the third brake light set up!
With only two lights you may not know, when one is out of action whether the
driver is trying to signal a turn or is tapping his brakes. The third and
upper light tells you 'Yes it's the brakes'. (That assumes that only one
regularly located brake bulb is out of action and the third (and usually
upper brake light) is OK.
 
J

John G

Jan 1, 1970
0
Terry said:
Is that legal?
BTW yesterday driving behind car with driver side rear brake light out
of action realized that's another advantage of the third brake light
set up!
With only two lights you may not know, when one is out of action
whether the driver is trying to signal a turn or is tapping his
brakes. The third and upper light tells you 'Yes it's the brakes'.
(That assumes that only one regularly located brake bulb is out of
action and the third (and usually upper brake light) is OK.
Mistaking a brake light for a turn signal has not been a problem in the
advanced world since 1960.
Only the flat earth society (USA) has persisted with this cheapskate
method for so long.
 
A

Anonymous AtWork

Jan 1, 1970
0
John said:
Mistaking a brake light for a turn signal has not been a problem in the
advanced world since 1960.
Only the flat earth society (USA) has persisted with this cheapskate
method for so long.

Wha? On my American-made truck the turn signal is orange and the brake
light red.
 
M

Michael A. Terrell

Jan 1, 1970
0
John said:
Mistaking a brake light for a turn signal has not been a problem in the
advanced world since 1960.
Only the flat earth society (USA) has persisted with this cheapskate
method for so long.


Once again you are full of misinformation about the US. Tail lights
on vehicles abandonded this method a long time ago.
John G

Wot's Your Real Problem?


Idoits spouting garbage comes to mind.
 
Bryan, there have been a few posts in reply to your question but other
than to raise the quasi relevant question of legality (I've seen them
flash on motorcycles) they're not really addressing your question.

The good news is 1) I know how to do it, 2) I've seen and have a
schematic for something really similar. The bad news is that I'm not
expert so my experiences and knowledge are limited (kinda the deaf,
dumb, and blind leading the blind. :)

That said, I read this schematic about 5 years ago and it was for
flashing the brake light on a motorcycle. There are two ways you can
decide to have that light flash; continuously while the brake light
circuit is energized or to have it flash some number of times and then
latch on (blink - blink - blink - stay on....). Either of them will be
simple to implement.

Let's put into words that which is easier said than done; locate the
wire that runs to the Elizabeth Dole light (third brake light),
preferably somewhere inside the car instead of inside the housing (for
space, appearance, and accessibility considerations). Bascially, just
cut the positive wire that goes to that brake light. The raw end of
the wire from the chassis is now your source voltage; it should have
voltage only when the brake light circuit is energized. The other raw
end, that goes to the Elizabeth Dole light is the output that you'll
hook up to your circuit you're going to build.

The circuit I use consists of basically 8 parts: one potentiometer
(100k), one capacitor (10 micro F), one 4049 hex buffer, one 4017
decade counter, one 680 Ohm resistors ,x number of 4148 diodes (the
number of outputs from the 4017 you intend to use), 1 2N4401
transistor, one more 4148 diode, and finally one relay.

It's a really simple thing once you've played with it and seen it
(believe me, electronics isn't my area of expertise and yet I think
it's pretty simple). The 4017 decade counter does just what it seems
like it would do; it counts input pulses. It sends one of 10 outputs
high (on) depending on the number of input pulses it gets. I use the
4049 hex buffer to generate the pulses (I have no idea how it does it,
I just read it in the original schematic I read). I tried to use a 555
timer to produce the pulses but could never get it to work right.
Anyway, the capacitor is used with the 4049 hex buffer I presume as a
filter, and the pot is used to adjust the output pulse frequency. The
4017 receives the pulses as input and sends each of its outputs high in
turn. You tie the output through a diode to the resistor. Then,
finally, you tie in the transistor, final diode, and relay. I don't
know why they used the transistor, but I suspect it's because the 4017
might not be able to sustain the load of the relay on it's outputs.
Here's where it gets fun.

If you want it to blink on and off three times and then stay on you
simply tie outputs 1, 3, 5, through diodes, to the resistor which is
tied to the transistor. Then you tie output 7 to the resistor AND to
the Clock Enable pin on the 4017 (tying its own output #7 to the Clock
Enable) which "freezes" the whole thing. It'll stay locked on like
that until the whole circuit gets reset (when the circuit loses power
when the brake circuit de-energizes as the pedal is released). The
output trips on the transistor which applies power (from the up-stream
brake circuit) to the relay (any NO automotive relay that can handle
the load (check out a horn relay for a 1998 Dodge Ram 1500 at an
autoparts store for around 8 bucks and which has nice-sized legs for
female blade connectors)). You use the second 4148 to kill any spike
voltage from the coil in the relay.

Now, I've never tried to see if one will reset when you cut power to
it, but the original schematic that I saw worked that way, I *think*.

Unfortunately, it's near impossible to try to describe to you what the
connections/schematic looks like in type. This link is now dead, but
if you could find some web archive site they might have it (I never
looked at this site/page before so I don't know if it would do what you
need or not):
http://www.electronics-lab.com/projects/automotive/002/index.html

Here's a link to a, I think, much more complicated setup, but the
schematic is nice and clean:
http://www.uoguelph.ca/~antoon/circ/flashing.htm

Unfortunately I don't have a site that would be available long enough
or reliably enough to post it in this reply. I can draw something up
and e-mail it to you, if you'd like, just let me know and post your
address and I'll see what I can do.

In the meantime, here's a simple idea...if you don't mind it flashing
constantly: http://www.oldengine.org/unfaq/sig1.htm

Super simple, it looks.

Anyway, hope that helps.

Take care.

--HC
 
B

Bryan

Jan 1, 1970
0
Thanks for the information.
I should have been more clear on the blinking area. I did wants it for a
duration they steady on. I have seen some vehicles with this in Arizona as
far as the legality aspect, I have not heard of any. I do have a motorcycle
as well and was looking to adapt the circuit to it as well as using LEDs.
Thanks again for your help. I will look into those sites. If you have any
other ideas as well, please feel free to let me know.

BA Sr.
 
H

HC

Jan 1, 1970
0
I have a drawing of the circuit, as an Adobe Acrobat document, and I
could prbably hack one out in Paint (I originally used Corel Draw! to
make the schematic, converted it to PDF and God only knows where that
Corel Draw! file went. :-/ I hate to be an ignorant wretch, but I
don' t know how to post a file to the 'groups. I'd be willing to send
you my schematic as a PDF, but I'd really like to do it here in the
'groups so others could benefit from it. Any suggestions of how I can
"post" a PDF in a 'group posting?

I can always send it to your e-mail address if you want to give that to
me, but like I say, I'd really like to send it to the group to help you
AND others.

--HC
 
S

stratus4[email protected]

Jan 1, 1970
0
Actually, I'm pretty sure I saw a recent model Ford that had the
brake/turn signal use the same lighting element. Flat earth, huh?
OK
GG
 
M

Michael A. Terrell

Jan 1, 1970
0
Actually, I'm pretty sure I saw a recent model Ford that had the
brake/turn signal use the same lighting element. Flat earth, huh?
OK
GG


It would be interesting because Ford claims to build "International
Designs". My neighbor bought a new full size Ford truck last year so
I'll check when I catch her at home. I don't recall seeing any new
vehicles without the separate light systems and it makes hauling a
conventional trailer even more interesting with all the variations in
wiring. On top of that, a lot of vehicles are imported from other
countries that use separate lamps for turn and brake lights.
 
H

HC

Jan 1, 1970
0
Well, that's not perfect but I guess it'll work; it's all text, it
should propagate beyond Google (I hope) and anybody with a copy of
Winzip can copy and paste it into a straight text file (Notepad), save
it as blinker.uue and then open it with Winzip.

--HC
 
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