555 Timer circuit!

In order to make your LEDs blink in a specific timing, you can use a 555 timer to set your "on" and "off" ratios.

(Here's a 555 timer)

and here's what I've used for one of my timer circuits. (pardon the ugly drawing).

Timing is given by the formula:

Time off = t=0.693 (resistor A + resistor B) * capacitor

Time on = t = 0.639 (resistor B)*capacitor

Therefore, with bigger resistors or capacitors, you can change your timings longer.

so for my circuit:

time off = 0.693 (250 000 ohm + 25 000 ohm) * 10x10^-6 F = 1.9 seconds

time on = 0.693 (25 000 ohm) * 10x10^-6 F = 0.17 seconds

Note: this is the timing for the back blinkers near the engines. (see next post)