A very simple yet interesting Chasing LED arrow car tun signal indicator circuit is discussed in this article.
The circuit uses just a single 10 stage Johnson’s decade counter IC 4017 and an UJT for executing a very interesting two pattern LED light chasing on the connected LEDs, which produce an impression of creating an arrow in a given direction. The following GIF image tells us how the pattern might look when its installed across the car turn signal slots.
As may be seen in the pattern, the LEDs are grouped in different numbers across the channels, and once illuminated these light up to produce a bar graph kind of chasing and single channel chasing effect alternately.
The circuit which is responsible for generating the above chasing LED arrow in a car tun signal indicator , can be witnessed below:
The idea looks pretty simple, a single IC 4017 is configured for carrying out the chasing LED in an altyernately bar graph and dot mode through a special smart arrangement of its pinouts across the connected LED series parallel channels.
The speed at which the chasing eect on the LEDs is supposed to happen is determined by the flashing rate of the UJT device at pin#14 of the IC4017.
The flashing or oscillating rate on the UJT can be fixed by adjusting the associated 100 pot or a preset or/and the 47uF capacitor.
This in turn determines how fast or how slow the LED chasing on the LEDs can be achieved.
Once installed this car LED chasing arrow turn signal indicator will instantly start producing the expected light show and produce the required turn signal indication in a much enhanced compared to the conventional single bulb flashing indicators