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LED bar

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bn1701

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Hi there

I have a 10 LED light bar and i would like to be able to turn each LED on sequentially from left to right. I would push one button (up) to turn a led on and another (down) to turn them off. If I push the up button ten times then all 10 leds would be on, if i pushed it 5 times then only the left most 5 leds would be on. The only way to turn them off would be to push the down button until all LEDS are off.

One solution I can think of that is close to what i need are those led drivers used for vu meters. The problems is that I don't see where push buttons could be used to adjust the reference voltage.
Another solution might be to use asynchronous up/down counters with the switches used to provide the clock pulses but the difficult part would be in decoding the BCD output to the sequence required.

Does anyone have any ideas on how I can implement this? I'd like to be able to fit this into a small package.

Thanks
 
The simplest way, with the lowest component count, and smallest size, would be to use a micro-controller. A PIC 16F628 would do nicely, your total project would consist of the 16F628, the LED display, 10 series resistors, two push button switches, two pull-up resistors for the switches (you could use the weak pull-ups on PortB instead of these), and a 5V supply.

By using a SM chip you could make it really small, but even without SM, an 18 pin DIL chip isn't very big.

You would have to write the software though, but my tutorials contain most of what you would need.
 
Another solution might be to use asynchronous up/down counters with the switches used to provide the clock pulses but the difficult part would be in decoding the BCD output to the sequence required.

You want a decade up/down counter. I attached a smaple of the timing diagram, I was looking on digikey, and it doesnt look like they have a 10 stage counter, just 4 stage, so you could just cascade 3 of them together?
they do have a 10 stage count up counter though.
I'm sure that there is something out there

hope this helps
 

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