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[A79coupe at aol.com]

In a message dated Wed, 7 Nov 2001  2:59:51 PM Eastern Standard Time, A70Duster at aol.com writes:

> My idea is to use the LM3914 10 LED Dot/Bar Display driver.  If you look at the volts to A/F ratio, the curve is "fairly" linear from 10:1 to 14.7:1.  Then the curve knees up and again is fairly linear from 14.7:1 to 20:1.
> 
> By drawing some lines in to guestimate how a linear device would respond to the curve, I see no more than 2% error.  The worst of the error bring around 14.7.  I envision two of the LM3914 working in concert.  Use one of the LM3914's in the rich region (green LEDs, 1.3 to 2.5 Vout) and the other LM3914 working in the lean region (red LEDs, 2.5 to 2.9+ Vout).
> 
> Some will say to use a voltmeter, but I'm an "analog gauge" fan cause they are quicker to read.
> 
> The circuit could be added to the WBO2 board (with the three "open chip" holes). 

Take a look in incoming at the WB disp.zip.  this is Bruce Roe's 40 led display for the WB.  Actually only 36 led's are actually used, but it measures from 10.0 AFR to 23.5 AFR in those 36 steps which means that each step is 3/8 of an AFR.  It is set up to be a zero center around Stoich, with led's lighting in bar graph fashion as you go rich/lean of stoich.  

Not fully analog, but IMHO much easier to read than a bouncing needle.

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