Can someone help me with a circuit that will light up 5 leds in parallel without usin

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Hi,
Are you sure that the first LED is always on? I can see it flashing
Use 4 I/O to control 9 LEDs (9 stages), possible? Since the max stages of using 4 I/O is 12.
 

ericgibbs, you seem to be on the right track, a triangle ramp voltage with the
LM3914. Can the triangle wave be clipped on top to allow the full heart to stay on for a shot period of time?
 

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This link has a video that explains charlieplexing very well

**broken link removed**

At 5:50 he says: "Only one LED can be ON at any given time" which means I can't turn on more than one led at any given time?...Just wanted to confirm this, I hope I'm wrong.


But then again I saw 3 videos at youtube about charlieplexing and they had more than one led on at a time.


Also at 9:32 he says: "this will give roughly 40mA of peak current going through each led"

then he says: "and therefore the average current through the led is 40mA/20=2mA", so I'm a bit confused isn't there a contradiction??

Please watch the whole video.
 
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iONic said:
ericgibbs, you seem to be on the right track, a triangle ramp voltage with the
LM3914. Can the triangle wave be clipped on top to allow the full heart to stay on for a shot period of time?
Click to expand...

hi,
I would try using 'two' LM outputs at the 'top' to drive the same LED set.
That would give the appearance of a longer on time.
 
Use a PIC with enough pins to drive each LED (or pair) and do away with the multiplexing.

This will make the code and the hardware very simple.

Like Erick says Good enough is Perfect.
 
Gordz said:
A PIC would be the answer here except the game plan was to use NO counters or decoder
Click to expand...

I think the OP has dropped that restriction.

The whole point of my project is to do it just like it is shown in the pictures so let's forget about the counter and timers.
Click to expand...
 
Ishikawa said:
At 5:50 he says: "Only one LED can be ON at any given time" which means I can't turn on more than one led at any given time?...Just wanted to confirm this, I hope I'm wrong.
Click to expand...

I already answered this above!.
 
bananasiong:
Hi,
Are you sure that the first LED is always on? I can see it flashing
Use 4 I/O to control 9 LEDs (9 stages), possible? Since the max stages of using 4 I/O is 12.
Click to expand...

Yep looks like it.

Nigel Goodwin: You do it so fast you can't tell they are flashing, it's a VERY standard technique.
Click to expand...

So I have to make the pic to switch between high and low at the 5 inputs fast enough so it won't look like the leds r turning on&off. Is this what u mean?

Thanks
 
Ishikawa said:
So I have to make the pic to switch between high and low at the 5 inputs fast enough so it won't look like the leds r turning on&off. Is this what u mean?
Click to expand...

Yes, check my PIC tutorials for an example of multiplexing LED's.
 
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