Thank you, I will try that soon and give a quick reply later. I tested the circuit in a breadboard which recently didn't come out well. But soon to fabricate if this all works well.

 

Elec_mech, I have tried to connect all the connections replacing the transistors with those switches, but it doesn't make anything? I connected the circuit in a breadboard and I am sure all connections are correct but when i tried to turn on the power, LEDs are not lighting.

 

Can you post a few good, clear pictures of your circuit?

 

that is what has done

 

Is there any differences when you use different component in this circuit? (ex. ceramic capacitor instead of electrolytic) but all in all its the same value, i checked all the connections and all the components but when i connected it to the source there is no response in the LEDs? what would you think is the problem?

 

I tried to connect the LEDs in parallel and disconnect it from the transistor of the Flashing Circuit to provide an output to the ground. The LEDs are lightened but now the switches are not working. I'd reviewed again the circuit why this is happening, but I have no idea where to trouble. I just have the confidence that all the ICs are working properly, and it is just some parts of the circuits are not working properly. Can you sight some problems here??

 

Bertus, don't you think this should be moved into a new thread?

 

MrChips

http://forum.allaboutcircuits.com/showthread.php?p=645397#post645397

here is the thread

 

How can I interface a keypad and two 7 segment display with 8051, to display two digit no

 

It's not good form to hijack a thread, particularly one that is nearly 2 years old.
Please start a new one of your own.