I have read most of that info but that is an excellent site.This article explains how the different sensors work and more importantly what the controller for the WBO2 sensor must be able to do:
http://www.wbo2.com/lsu/lsuworks.htm
I know that and the reason I want to make a meter ... so the original question was how to interpolate that voltage into a air/fuel ratio?Don't bother with the narrow band sensors. They, in practice, only tell the vechicle computer if the mixture is lean or rich. If you tap into your vechicles computer and everything is functioning properly the o2 sensor waveform looks somewhat like a sinewave centered @.45 volts. .45 volts being 14.7 AF ratio. However this is only in "closed loop" mode. IE cruising down the highway. The wide band will tell you not only if you are @14.7 af ratio when cruising, but more importantly what your af ratio is under acceleration. Under this situation, the vechicle computer then ignores the o2 signal and goes to pre-programed "maps" to set the injector pulse widths. THIS is where the wideband shines and gives the hotrodder/tuner the information to modify the af ratio and make more power.
A WBO2 sensor by itself provides no readily useable information. There is no way to interpolate anything with it by itself. It must have the controller circuitry to get a useful AFR signal.... so the original question was how to interpolate that voltage into a air/fuel ratio?
That was what I was trying to allude to in my earlier post. It seems to me to have a AFR reading one needs access to both O2 level and air flow measurement, so I thought the O2 sensor by it's self would be of little value, wide band or not. A ratio reading implies knowing two quantities, no?A WBO2 sensor by itself provides no readily useable information. There is no way to interpolate anything with it by itself. It must have the controller circuitry to get a useful AFR signal.
You mean 1.47 volts for 14.7:1 right? It would take a bit of work to get 14.7 volts from a 12 volt system.Example 1.20 volts is 12-1, 14.7 volts is 14.7-1 etc.
I also have the LM-1 but what you are talking about is the analogue output from that meter ... not from the 02 sensor. It provides a linear output from 0-2 volts.Yes, 1.47 volts = 14.7 afr when programmed that way. To measure afr one only needs the wideband sensor and associated circuit. The MAP sensor (along with other sensors) gives the engine computer information to determine ignition advance and injector pulse width.