O2 sensor led meter-K&N ref.

[Sean Magnuson]

        You hit the jackpot with that one Robert!  K&N has marketed  an
air/fuel ratio monitor for several years that uses that very chip.  I
actually purchased one a couple of years ago for my 1986 FJ1200 motorcycle
@ almost $200, decided to take it apart, and found that they tried to
scrape the IC number off the chip.  Using a simple dissecting microscope
and some vegetable oil to clarify the number, I was able to identify the
chip as good ol' LM 3914.  Needless to say I was ticked-off at the fact
that I was able to reproduce the exact circuit for less than $6, including
all electronics except the 02 sensor (add an extra $30 for a single lead
sensor).  I thought of marketing the same product myself, since they
apparently don't have any patent or license protection on the circuit ( I
checked ), but "pirate" versions have been popping-up all over the place,
so I decided against it.  If you want to make your own 10 segment led meter
or larger, all you need to do is follow the info. in the spec sheet from
Digikey and pot it in colored epoxy or polyurethane for an attractive,
weatherproof, completely functional unit.  Total price ~$40 (including 02
sensor).


Sean Magnuson

Cornell University

Motorcycle Performance Nut