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Variable and alternating flashing LED...

buttr

Jan 4, 2021
2
Joined
Jan 4, 2021
Messages
2
Hi
So I know it's probably super simple but I haven't found anywhere else that has an answer I need so I am taking to here to find it.

I was wondering what stuff I would need to make a variable and alternating flashing LED with a certain flashing pattern?

I have already made a variable flasher for one LED using a 555 which im quite proud of however next up is 2 LEDs which flashes the Left LED 3 times, then the Right LED 3 times.
So I was wondering if it could be achieved without a microcontroller?
( I have an arduino, but I have to use it for other things)
Thanks.
 

Martaine2005

May 12, 2015
4,351
Joined
May 12, 2015
Messages
4,351
You can use a CD4017 and use diode steering.
It has 10 outputs, you would use 6 of these.
Example: 2 LEDs per output.
Out1 to both LEDs via a 1N4148.
Out2 to same LEDs via diode.
Out3 to same etc. That’s your first three flashes.
Next is your other two LEDs:
Out4 to other LEDs via 1N4148.
Out5 to same LEDs via diode.
Out6 to same .
This will flash the two LEDs three times then the other two LEDs three times.

Edit: only two LEDs, so left 3 times and right 3 times
Martin
 

buttr

Jan 4, 2021
2
Joined
Jan 4, 2021
Messages
2
You can use a CD4017 and use diode steering.
It has 10 outputs, you would use 6 of these.
Example: 2 LEDs per output.
Out1 to both LEDs via a 1N4148.
Out2 to same LEDs via diode.
Out3 to same etc. That’s your first three flashes.
Next is your other two LEDs:
Out4 to other LEDs via 1N4148.
Out5 to same LEDs via diode.
Out6 to same .
This will flash the two LEDs three times then the other two LEDs three times.

Edit: only two LEDs, so left 3 times and right 3 times
Martin
Ah bang on, exactly what I'm looking for...
In my 555 circuit, i had a Potentiometer to adjust the flashing speed... Is there a way I could include that in the circuit or at least have a way to speed up the flashes?
Thanks.
 

Martaine2005

May 12, 2015
4,351
Joined
May 12, 2015
Messages
4,351
In my 555 circuit, i had a Potentiometer to adjust the flashing speed.
Of course, the 555 output pin 3 connects to the 4017 input pin 14.
The 4017 is a little strange, it’s outputs are not in sequence. Instead of 1,2,3 etc, it’s 3,2,4,7 etc so look at the data sheet.

Martin
 
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