"Timer switch " for the device

Z

zerostar

Member

• Jul 13, 2012

• #1

Hi,
I am new in electronic area and making a little device and the test show in following link:

https://www.youtube.com/watch?v=f7QcDoDeWJY&feature=youtu.be

Ther problem is, is there are any timer switch can be applied on it? I want it operate for a while ( around 10seconds) after release the button.



Thank a lot

 

K

KMoffett

Well-Known Member

• Jul 13, 2012

• #2

Sure! What are the voltage and current requirements of the "smoke" generator device?

Ken

 

Z

zerostar

Member

• Jul 13, 2012

• #3

voltage : less than 6V ( 1.2V *4 is used)
current : not sure

Is 555 IC can be applied on this stuff?

 

K

KMoffett

Well-Known Member

• Jul 14, 2012

• #4

Yes! If the generator current is under 200mA you can drive it directly from the 555's output. If greater than 200mA, you will need a transistor or MOSFET (better) driver between the 555 ant the generator.

Ken

On second thought, after rereading the 555 datasheets, with a 4.5v supply I would definitely use a drive transistor or logic-level MOSFET.

Ken

 

Last edited: Jul 14, 2012

Z

zerostar

Member

• Jul 14, 2012

• #5

But which circuit is suitable for the stuff? Any recommendation?

 

K

KMoffett

Well-Known Member

• Jul 14, 2012

• #6

Here is a 555 monostable circuit that should work. Be aware the the 555 will need to be continuously powered. In you use the CMOC version (LMC555) instead of the transistor version (LM555) the quiescent current will be much less...100uA vs 3mA.

Ken

 

Z

zerostar

Member

• Jul 14, 2012

• #7

OKOK,thanks a lot, can you pm me your facebook or email to me if you don't mind?
I got so much problems like this and seek for help

 

K

KMoffett

Well-Known Member

• Jul 14, 2012

• #8

I can do that, but posting you "problems" here will get you a wider range of possible solutions. People here are very helpful and creative, and love the challenges of using their knowledge and experience in solving posters' problems.

Ken

 

Z

zerostar

Member

• Jul 14, 2012

• #9

thanks.