LED sequentially off circuit. HELP!

[desperado]

basically, i need a circuit with 3 bi-color(red, green) LEDs.
Once you turn on the switch, the three LED will turn on. After then, the red LEDs will turn off one by one.
After all the red LEDs off, three green LEDs will turn on and buzzer will ring.
The circuit can be reset by turn off and on again the switch.

i tried using the method
**broken link removed**

but it didnt work although it was close to what i wanted.

i also tried using the 555 timer circuit but i just cant make 3 LED's light up at the start at the same time.

HELP pls.

 

[Veraxis]

Hopefully this should help. It uses a NAND gate and a NOR gate which is enabled by a decade counter. I'm sorry if all of the diodes get a little crazy by the end, and my hand-drawn diagram does not help, but it should all work. the potentiometer on the 555 will allow you to control how fast the diodes "count down".

 

[Raikkonen]

Hello, I am new to circuit and intereted to build the LED sequential circuit(LED sequentially off circuit. HELP!) that you have posted, but which Nand gate should I use? (CMOS 4011: Quad 2-input NAND gate or TTL 7400: Quad 2-input NAND gate)? Thank you.

 

[Veraxis]

Here is a corrected version of the latter part of the circuit.

 

[colin55]

The circuit above won't work.

Here's a circuit that will work:
**broken link removed**