Need help with a LED control circuit

[aviator91]

aviator91 led

Hi all,

I’m fairly new to electronics but I do have the basics ..... and I was wondering if I could get some help from you guys?

I need to control 3 LED’s (torch / flash light) with 1 NO momentary push button switch.

I saw a circuit / project on a web site using a 4017 Decade Counter which closely resembled what I was looking for, however I don’t have the expertise to reconstruct the circuit to suit my application. **broken link removed**

The result I’m after is;

1st push of the switch should light 2 LED’s together
2nd push of the switch should light 3rd LED on its own
3rd push all OFF

I’m using 3 x AAA batteries, and 3 x 16000mcd WHITE LEDs

Is the 4017 counter the right IC for my application? I've seen some switch IC's (ADG719 or MAX4714) can something be designed to give similar results to my Flashlight project ??

Thank you in advance,

 

[IORY]

LED control circuit help

Hello aviator91:

What is the pattern of the switch you use?
Is the switch that you give it a push then it can bound up?

or you can only close it or open it ?

 

[mabdelmawla]

Re: LED control circuit help

connect Q1 of 4017 to the (+) terminal of the 1st and 2nd LEDs and the (-) terminal to the GND.
connect Q2 of 4017 to (+) terminal of the 3rd LED and (-) terminal to the GND
connect Q3 of 4017 to (Reset) of 4017.
connect your Push button to the gnd and CK of 4017. be sure that your button is bounce free.

 

[aviator91]

Re: LED control circuit help

Hi Ivory

The switch is a miniture Normally Open momentary.

push once and opens again ....

thanks

Added after 24 minutes:

OK,

I'll draw the circuit you describe and see what I come up with ...

Are limiting resistors still required on the anode of the LED even though they are 3V white and there are 3 in the circuit with an input of 4.5V?

concernig the switch you mean a debouncing circuit right??

I'm kind of using smaller circuits I've come across as building blocks, Is this the right approach?

thanks.
Alf

 

[mabdelmawla]

Re: LED control circuit help

Yes, I ment debouncing circuit

and about the limiting resistor. I don't think you need them. but chech first from the datasheet of 4017 the output resistor and the maximum sourcing current for output nodes.

but I tried it befor without limiting resistor, and it was ok

 

[aviator91]

Re: LED control circuit help

Are there any other packages which are readily available and would do the same job Easier / Better ??

 

[mabdelmawla]

Re: LED control circuit help

I don't think so. but try it 1st. it's very easy. and if you faced any problem, just ask

 

[DHIV]

Re: LED control circuit help

hai
you just draw truth table and proceed with k-mapping to get the boolean expression for your LEDs separately. Then you can easily get your requirement just by using gates