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Re: O2 LED meter

Todd Young <tyoung@wamnet.com> wrote:
> My apologies to Igor Kessel, who has a LED O2 meter and wanted to market
> his version. He may still be able to, for those who don't work with
> electronics, but I found this and just had to pass it on.
> http://efi332.eng.ohio-state.edu/diy_efi/projects/projects.html
> HTH some people, it will me.

The schematics for LM3914 at the URL above were taken from the National's
standard applications book. It's public domain and could be found in any
engineer's lab.
Those interested in replicating my unit can add one or two cascades of
amplification before the LM3914 to boost the input voltage to 3v, but you'll
have to use three LM3914 for the wide band multi-colour output. All chips that I
used were surface mounted in order to fit two PCBs into a standard round 52mm
plastic gauge housing. When selecting an amplifier choose one with a highest
input impedance. You don't want to shunt the brain by a low impedance load.
And then there's an issue of coupling of the three LM3914 so that the 2nd picks
up where the 1st left off etc.

Curiously, at the URL above the "EGOR (True wide range O2 sensor)" clickable
link leads to a blank page with: "Put EGOR info here".

Somebody has intended to put my device on the net without obtaining my
permission first AND misspelled my name in the process. Hmmm.
Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- mostly stock
Philadelphia, PA