New style 3rd brake light

[dacflyer]

hi all , i have seen these new 3rd brake light on newer cars here lately, the 3rd brake light will flash a few seconds then stay on...<p>i was thinking,, can this be done with a 556 timer and a relay?
1st part of timer acting as the flasher part,,and the 2nd one acting as low ( off ) untill certain time, then goes hi ( on )? both outputs connected together,,with dioads to prevent backflow into the other output...and then this output going to the relay? do i have the right idea? will this work or is there a simpler way ?

[Bernius1]

FIRST OFF, SUPER-BRIGHT LED'S OR LOW-POWER BULBS
FOR OUTPUT, DRIVEN BY TIP-29C OR 2N3055 TRANSISTORS. RELAYS SHOULDN'T BE NECESSARY.
AS FOR THE TIMERS, A 556 IS TIMED BY AN EXTERNAL R/C NETWORK, SO I WOULD:\
TIME 1/2 FOR 2hz FREE RUNNING FOR THE BLINK
SET THE OTHER 1/2 FOR STABLE HIGH OUT AFTER
2-SECONDS ( APPROX ) , & TAKE A FEED OFF ITS
OUTPUT, & RETURN TO THE THRESHOLD OF THE
FIRST TIMER. BY DRIVING THE THRESHOLD TO Vcc
OF THE 1st 1/2, IT SHOULD TURN OFF.

[bobsRAC]

Just to throw it in there... MOSFET switches are cheaper and more effective than big BJTs for simple on-off, low-speed switching.<p>As an example, for $2.52 in quantities of (1), the IRF1404 from International Rectifier has an on resistance of 0.007 Ohms max at 160dC. Therefore, at 100A, there is a 0.7v drop worst case.<p>A more practical number for LED array switching might be 1A. At 1A and 0.004 Ohms, there is a switching loss of 4mW, as compared to the BJT which will dissipate approx 700mW.

[dacflyer]

ok, thanx,, so i am thinking on the right track then,,

[dacflyer]

ok, heres part 2 of my idea,,,
how can i configure 555 timer to auto start timing as soon as power is applied..
a diagram whould be nice if possible...
i want it to auto start timing for about 5 seconds then end,untill power is re-applied..