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LED meter drivers

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Thomas Stegen

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Jan 27, 2004, 6:01:17 AM1/27/04
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Hi there.

I am looking for and LED meter driver which operates
based on a 0 to 12 volt squarewave. I want the number of
LEDs to light up to be proportional to the frequency of
the square wave. Ideal would be 15 outputs, but need not
be excact. I have been looking in some catalogues, but I
have a bit of trouble deciphering all those codes and stuff.
If anyone can help me with some of this it would be appreciated.
(Should be available from Britain btw).

I will be able to use a frequency converter.

If it matters:
It is to be used in a car, in british weather conditions,
Not to hot or cold.

Harry Bloomfield

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Jan 27, 2004, 11:37:27 AM1/27/04
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Thomas Stegen wrote on 27/01/2004 :-

> I am looking for and LED meter driver which operates
> based on a 0 to 12 volt squarewave. I want the number of
> LEDs to light up to be proportional to the frequency of
> the square wave. Ideal would be 15 outputs, but need not
> be excact. I have been looking in some catalogues, but I
> have a bit of trouble deciphering all those codes and stuff.
> If anyone can help me with some of this it would be appreciated.
> (Should be available from Britain btw).

That is not a very well written specification, however....

Take a look at a frequency to voltage IC such as the 9400. On the
voltage output of that you will need an LED bargraph IC. These allow
for 8 LED's per IC and the display can be set either for single point
lit or a solid bar. These IC's can be cascaded to produce 8, 16 or 24
LED diplays in a single bargraph.

It sounds as if you are trying to build a tachometer, if so beware that
the voltage pulse at the ignition coil will require some conditioning
before being fed into the 9400.

--
Regards,
Harry (M1BYT)...

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