I have made this: **broken link removed**
The problem is that LED do fade in, but stays on all the time. I want it to fade in (cca 3sec), stay on(1 sec), fade out (3 sec), stay off (1 sec)... Times arent a big deal, just dont want it to go too fast. I want to make a beating hearth of this, with 21 LEDs..
If you have a capacitor/resistor based charge/discharge LED driver switch at the output of an astable timer circuit, you have that automatic fade in/fade-out cycle effect I think. Check it out.
Try omitting the connection from pin 7 to transistor base(B) and re-wire a connection from pin 6 to the base. Rest of the connections leave as is. You can experiment with different cap values.
Neither the Instructables circuit nor the modification above can provide the repeating fade-in/hold/fade-out/hold sequence you want . Additional timing components will be needed. It is the transistor base current in the circuits shown which prevents the capacitor charging sufficiently to reach the 555 threshold to give a repeating sequence with fade-out. Furthermore, putting LEDs directly in parallel as shown is not good practice; each should have a respective series resistor to allow for manufacturing tolerances.