Questions about EGOR

[Ludis Langens]

What sort of power source does EGOR need (not counting the heater)? 
12V?  5V?  Both?

How much current is needed at 5V?  Putting this another way, is the
current draw low enough to use an ECM's regulated 5V output meant for
sensors (TPS & MAP)?

Could EGOR use dual 5V supplies - one for internal circuitry, and one
for the source of current sent to the O2 sensor?  The idea is to protect
against short circuits in external wiring.  If the O2 harness gets
mangled by a fan, or melted by a manifold, thus shorting all the wires
to ground, the sensor supply can shut off.  The internal supply can keep
working, allowing an error code to be reported.

Is EGOR's 0 to 5V signal output range a "natural" range?  How much of a
load can the output drive?  It appears that GM ECM's often have an
unused analog input with a 1000 ohm pullup to 5V.  Can EGOR drive this?

Can EGOR be designed with an output range of about 1 volt?  This would
allow EGOR to directly drive an ECM's existing O2 input(s).  (It's a
trivial matter to edit a PROM to handle a different O2 input voltage
profile.)

Alternately, does it make sense to monitor one of EGOR's O2 cells using
an ECM's existing (differential input) O2 amp?

How big will EGOR's circuit board be?


I went to a library and looked up how Honda wires their "LAF" O2
sensor.  This sensor is used only on the 49 state '92-'95+ Civic 1.5
VTEC.  The California emissions version of the same car&engine gets a
standard 4 wire heated O2 sensor.

The pin-3 end of the calibration resistor is grounded.  The pin-4 end of
the resistor is driven from 0.3 to 4.9 volts by the ECM.

The pin-2 end of the heater is grounded.  The pin-1 end is driven from
the ECM.  This is different from all other Honda heated O2 sensors -
which connect between "hot" and the ECM.  Both types use the same ECM
pin for the heater output.  The trouble shooting flowchart implies that
the heater is driven with 7 volts.  (However, the flowchart never ends
in a "no problems" box - the 7 volts might be a failure response.)

Pin 8 (IP- and VS-, i.e. the cell common connection) is at 2.6 to 2.8
volts when the engine is running.  Pin 7 (IP+) should be 0.4 volts.  And
pin 6 (VS+) should be greater than 5 volts.

               unsigned long BinToBCD(unsigned long i) {unsigned long t;
Ludis Langens     return i ? (t = BinToBCD(i >> 1), (t << 1) + (i & 1) + 
ludis at cruzers.com            (t + 858993459 >> 2 & 572662306) * 3) : 0;}