Automobile turn signal circuit.

Here is a simple circuit that can be used as a sequential signal light in automobiles. The circuit is based on two ICs. A TS 555 CN CMOS timer IC and a CD4017 decade counter IC. The IC1 is wired as an astable multivibrator to trigger the counter IC. When triggered, the outputs of the IC 2 (pins 3, 2, 4 and 7) will go high and low in sequence and the speed of this sequencing will be proportional to the triggering frequency. The transistors Q1 to Q4 drives the corresponding LEDs. The switch S1 can be used to select the direction of turning and the LEDs arranged at the corresponding side of the vehicle will start sequencing.
Notes. 
 
* The switch S1 can be the existing changeover switch of the vehicle it self.
* The circuit can be powered of the 12V available from the vehicle itself.
* The color of the LED depends on your choice .
* The ICs must be mounted on IC holders.
* Assemble the circuit on a good quality PCB .
* Be careful with the wiring of this circuit  because any wrong connection may put the electricals of your vehicle in trouble.