Better yet, measure the LEDs you have, and design around them.

I tried looking up that design, it is has been modified off of something I drew, but as AG pointed out there are substantial mistakes.

Using a emitter follower you can eliminate the base resistor, but never try using a common emitter as you have without a base resistor.

Why not use the previous design with the emitter follower? It has a few less parts, and does exactly what you wanted to.

One of the biggest mistakes you can make is to keep changing what you want to do. Pick a design, then build it. The continual redesign with different specs is a major mistake.

 

Why not use the previous design with the emitter follower? It has a few less parts, and does exactly what you wanted to.

The function went to the opposite....It goes on flashing when ldr exposed to light but when the ldr going in dark,the leds kept illuminate the whole time(it should suppose went off).

Then audioguru told me on the post #60: "Bill changed the output transistor to an emitter-follower so it no longer inverts. Then the circuit lights the LEDs continuously when the second Cmos 555 is reset (you want them to be off)"

So,i use the design with diode and the output with the common emitter transistor and so far the function was better.