Power sequencer for LED bar graph needed

[J. Muniz]

Hi
I'm trying to find someone that can either direct me to an IC that
can sequentially light a 10 LED bar graph or someone that can program
a digital PIC to do it for me. Basically I want to have the LEDs light
sequentially from number 1 to number 10 upon activation and then be
able to shut down in reverse order once switch is pushed again. Power
supply will be 9v (can reduce).
Any links or advice would be greatly appreciated. Thank you


Joe

 

[Robert C Monsen]

Hi
I'm trying to find someone that can either direct me to an IC that
can sequentially light a 10 LED bar graph or someone that can program
a digital PIC to do it for me. Basically I want to have the LEDs light
sequentially from number 1 to number 10 upon activation and then be
able to shut down in reverse order once switch is pushed again. Power
supply will be 9v (can reduce).
Any links or advice would be greatly appreciated. Thank you


Joe

This may work

http://cache.national.com/ds/LM/LM3915.pdf

 

[John Woodgate]

I read in sci.electronics.design that Robert C Monsen

This may work

http://cache.national.com/ds/LM/LM3915.pdf

The 3915 has a non-linear response to input voltage. The 3914 is more
suitable for the OP's application. But that only takes care of the
driving of the 10 LEDs. In addition, a gated sawtooth or triangle wave
source is required, plus a basic 'push-push' bistable input circuit.

 

[Terry Pinnell]

This may work

http://cache.national.com/ds/LM/LM3915.pdf

You could easily adapt the circuit I posted here a couple of years
ago:
http://www.terrypin.dial.pipex.com/Images/Sequencer6LEDs.gif

Essentially, you'd configure the 3914 as a voltmeter in bar mode,
apply a gradually increasing voltage by charging a capacitor (either
linearly, with a constant current source, or exponentially if you're
not fussy about the rate slowing down for later LEDs), then discharge
it again after an appropriate time.