Simple Code Lock


Joined Sep 20, 2004
Originally posted by dan1986@Sep 20 2004, 02:48 PM
Hi People,
I am planning to build the following circuit,, as part of my A level studies. I was just wondering if anyone could tell me if the keypad used in the circuit was a standard key pad as shown at this address:

Any help with this subject would be greatly appreciated,

[post=2574]Quoted post[/post]​
I did not understand your point.Any how D-flip flop's input is connected to low.So last flipflop's o/p will be lo itself.Which will turn off transistor and relay.
So try connecting D1 to a high Vg.


Joined Sep 26, 2008
is this circuit really working.. kindly reply pls..

and i am trying to introduce on the circuit.. delay for the activation of relay and resetting.. but I don't know where to start.. can someone help me with that.. i would be very thankful.. thanks..

what kind of timing circuit do I need to use.. astable or monostable?



Joined May 16, 2005
Hello, Haylin. Welcome to AAC.

Please note this thread is a very old one, and a fairly random procession of unconnected thoughts. Most of the participants of this thread have not been around for years, and are not likely to see your question.

It would be far better for you to begin a new thread using the "new thread" button. Be sure to read these first:

Remember: the more detail you provide, the more help we can give.

I hope you have a fruitful stay.