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

Ishikawa said:

So I need 4 inputs to drive the 8 leds.

From the picture there is 5 wires:

One for the first led always on
One for Ground
The other 3 for the 8 leds (remember the 8 leds r actually considered to be 15)

However from the equation above, 3 inputs drive only 6 leds and there 8 left.

I'm I wrong???

Thanks

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ericgibbs said:

hi,
Looking at your 1st posting LED pattern, I would agree with Gordz, a LM3914 set for bar mode. Drive the input of the LM3914 with a ramp voltage.

If your LED's require more current than the LM can supply, use the LM to drive 4/5 transistors, which drive the LED's.

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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?

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Ishikawa said:

without using a counter/decoder??

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Gordz said:

A PIC would be the answer here except the game plan was to use NO counters or decoder

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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.

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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.

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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.

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

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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?

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