about 555 timer & and Voltage stepping down

[noidea]

hi,

i have 2 problems here.

1) 555 Timer. is 555 timer able to:

when something is activated(switch or any thing that trigger) the 555 timer can activate a LED and the LED would blink for 5 seconds and goes off on itself. Any1 can help me on the circuit design/diagram on how can it work? thanks..


2) About Voltage stepping down.. is there any other ways i can step down Voltage other den using RESISTORS? Example:

INPUT(12V to sensor) ---> SENSOR ---> OUTPUT(needed 5V going into a IC chip, so i think a Voltage step down method needed to be implemented but any other ways other den using resistors?)

Thanks for reading i hope someone can really help.. Take care

 

[nicleo]

hi,

i have 2 problems here.

1) 555 Timer. is 555 timer able to:

when something is activated(switch or any thing that trigger) the 555 timer can activate a LED and the LED would blink for 5 seconds and goes off on itself. Any1 can help me on the circuit design/diagram on how can it work? thanks..


2) About Voltage stepping down.. is there any other ways i can step down Voltage other den using RESISTORS? Example:

INPUT(12V to sensor) ---> SENSOR ---> OUTPUT(needed 5V going into a IC chip, so i think a Voltage step down method needed to be implemented but any other ways other den using resistors?)

Thanks for reading i hope someone can really help.. Take care

1) As '555 timer' itself implies, you can use it as 'timer' and you can adjust the timer (R and C value) so that your LED can blink according to the time interval you want.

2) You can use linear regulator (7805) or switching regulator (buck converter).

 

[noidea]

hello thanks for the info.. i try to study those kinds of regulators..

 

[papyaki]

Hi,

For 1), you can use two 555. The first one as a monostable and the second one as an astable. The astable period be the blinking period of the LED diode. The monostable period should be 5 second. The monostable output (3) should be connected to the reset pin (4) of the astable.

 

[noidea]

Hi,

For 1), you can use two 555. The first one as a monostable and the second one as an astable. The astable period be the blinking period of the LED diode. The monostable period should be 5 second. The monostable output (3) should be connected to the reset pin (4) of the astable.

hmmm thanks alot.. hmmm. the mono output(3) connect to (4) of astable rite..

but isn't the (4) of astable is connect to ground? so if i am to connect to astable's pin (4) should it be connect to ground too? or the monos output alone connected to astable (4)?

 

[lokeyh]

Why not use a counter to count 5 seconds and use some combinational logic to mask the output to the LED after that?

 

[papyaki]

Hi,

You need two 555. The first is a monostable, the second is an astable. In normal astable configuration, reset pin (4) is connected to Vcc. In the configuration I described, it should be disconnected from Vcc and connected to output pin (3) of the monostable.

 

[noidea]

ok thanks alot guys for helping.. i will try out the curcuit tomorrow for the 55 timer..

stepping down of voltage stiull working on it