LED fading - 555 timer

[rascupanamuha]

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..

What do i need to change?

 

[4pyros]

What kind of leds are you using and how many?

 

[rascupanamuha]

5mm, red, 20mA..
21 peaces

 

[transistor495]

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.

 

[rascupanamuha]

I have everything like on schematics, and it only does fade in, and stays on. It doesnt ever fade out, and repeat the cycle

I replaced transistor with a new one 2n2222, and capacitor to 47uF and now it only faster fade in, and also stays on all the time..

 

[transistor495]

I altered the circuit:

View attachment 69182

 

[alec_t]

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.

 

[audioguru]

Many intructables were designed by little kids who are only 10 years old. So the circuits DO NOT WORK!

 

[4pyros]

Some of this thread seems to be missing.

 

[Ian Rogers]

Some of this thread seems to be missing.

Oh! only about 4 days worth.... Still at lest its back online.