Double LED Flasher with 555 Timer and 4N25 Optocoupler

Here the circuit diagram of Double LED Flasher with 555 Timer and 4N25 Optocoupler. The circuit is working with timer IC 555 to create alternating flashes from both LED D1-2. The LED which used for this circuit can be different color from each other. The frequency of rotation can be adjusted by the trimmer R3 and by change the capacitance of the C1. For the power supply adapter, you can use a standart DC battery or a 9V DC power supply. One use of the circuit is to create alarm indication. Is it possible connected in parallel with the diodes D1-2, the optocoupler IC2-3, which lead to external circuits for various uses and purposes.

Components List:

R1,R2 = 1.5Kohm
R3 = 250Kohm trimmer/pot
R4,R5 = 470 ohm
C1 = 10uF/16V
C2 = 100nF/63V
C3 = 100uF/16V
D1,D2 = LED 3mm
IC1 = 555 Timer IC
IC2,IC3 = 4N25 optocoupler
S1= Push Button or switch on-off
BATT = 9V Battery