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How to use momentary switch to blink a led for 5 sec? Answered

Hello, I'm not able to find cheap toggle switch button waterproof that just on/off my blinking led but a 5sec timer can do it. 

I'm currently using this to make the led blink :

9014 transistor, LED 5mm, 30K resistor, 510ohm resistor, 22uf capacitor.

I want to add momentary switch to make it blink for 5-7sec.

Thank you

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iceng
iceng

Best Answer 4 years ago

By blink do you mean once you push and release the momentary switch the led will light ONCE for a duration of about 5 to 7 sec.

Be sure to click the picture to see the whole image....

6sec-oneshot-circuit.JPG
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FrançoisB14
FrançoisB14

Answer 4 years ago

I mean the led will blink for 5-7sec after the push to recreate a toggle switch activated for 5-7sec.

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iceng
iceng

Answer 4 years ago

Blink means ONfor RC time then OFF... What do you mean by blink ?

Are you asking for the LED to repeatedly pulse on_off_on_off_on_off while the toggle switch is activated ( then you would need to specify the OFF duration )

and such a circuit is called a switched oscillator....

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FrançoisB14
FrançoisB14

Answer 4 years ago

I mean I want to simulate an on/off toggle switch with a momentary switch to make a led blink for 5-7sec. Which means the led will on/off/on/off/on/off for 5-7sec after the button is pressed.

0
iceng
iceng

Answer 4 years ago

Here is a timed oscillator 2.8 cps with a 50% duty cycle... If that is too fast

make C3 a 2uF15v capacitor for 1.4 Hertz

Again be sure to click the picture to see the whole image....

6sec-ocs.JPG
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FrançoisB14
FrançoisB14

Answer 4 years ago

Ok thanks it looks nice.

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rickharris
rickharris

Answer 4 years ago

OR sometimes Iceng is even better than Google :-)

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rickharris
rickharris

4 years ago

You need something that can be triggered. a 555 timer is the first thing to come to my mind. LOTS of web pages showing how to use it. Google will be your best mate .

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FrançoisB14
FrançoisB14

Answer 4 years ago

Ok I've found out 2 instructables to do it. https://www.instructables.com/id/Flashing-LED-using-555-Timer/ https://www.instructables.com/id/555-Timer/ . But I'm not sure how to combine both. One will always flash the led and the other will stay it up for 5sec. How to combine both? Just adding a capacitor in front of the 5sec led?

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Josehf Murchison
Josehf Murchison

4 years ago

I assume you are using a single transistor inverter circuit configuration as a one shot.

Use a larger capacitor on the base if you are.