Yes wery close. Imagine driving in a normal manual control sistem vehicle. Usualy, when you set the air right and all is warmed up, you rarely touch the air control while driving. But then sometimes comes a situation where you want to squeeze the air just a tad. Long idle, trafficlights… we usualy do this beforehand based on experiances. but soon you are on your way you open it up again. Well its those occasions l think this wuld be usefull. And those occasions are plenty, we are just lazy and settke for some middleground setting because noone wants to fidle with the valve at every stop sign. But its a shame, we loose performance this way
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Why does the Arduino need 0-5v? Im not sure but it seems thats not the case…
A narrowband sensor has its scochiometric ratio at about 0.5v. If voltage drops to about 0.25v, we get to the lean zone. All the arduino needs to know is if the voltage is 0.25v or below, it shuld output a signal to the air valve to be closed. Well thats my thod, lm sure there are hidden catches but in principal it shuld work.
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Hey, wanna hear a nother redneck solution? You know those fancy 10 dollar air fuel guages most guys like to put in their trucks? They got a LED strip around them… lm wondering if we can take the signals from those led lighs to talk to our Arduino… nice and linear motion…
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No way around the AEM spend the money! There is nothing better on the market and you must have this good quality high definition signal.
You dont need to re invent this either. There is well developed code already here on this forum. This code started development back in 2014 and has evolved since then and is now tried and true.
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I find this interesting, has been in to electronic auto-mixers some, and there has been many automixers made with “simple” lambda sensors, they use to be based on a threshold voltage (the sweet spot, not necessary stochiometric) the electronic use to read the value in interval’s, second or milliseconds, “asking” low or high? Then close or open secondary air valve a small step, the time and size of step has to be tweaked in, to avoid hysteresis.
All this should be easy to do with arduino, the ones i’ve experimented with has been based on the “classical” 555 timer (3 of them, one for sample time, one for setting “frequency” to control a standard rc-servo.)
Isn’t there some very good info in the Thrive of grid-thread?
And yes, a wide-band lambda should be the best solution, to get a steady control, the ones i describe often has to be bypassed, or “manipulated” but works well with highway, steady driving.
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The signal voltage range is less than one volt. This is not enough definition. I have mapped those sensors to a higher definition range with no success. You can also set the Arduino to a 1 volt working range. Tried that too and it didnt work. The signal was just all over the place and it would not run stable.
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And a question: someone know if wide-band lambda sensors have a “standard” or if they differ between car manufacturers?
I have saved some from work, that are replaced, but not the reason to the “check engine” i believe these are good enough for experimenting. 
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The signal of those can be a real trouble, when i experimented i used high-class coaxial antenna wire for the signal, common ground for sensor and “control box”
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AEM has proprietary internals and are exclusive to them. The O2 sensor is from Bosch. Its a 6 wire sensor, if anyone can come up with any info on what each wire is for send it my way. I couldn’t figure out how they work other the heater wiring. So stuck with what was working and just ran the AEM gauge and lambda out.
Tell ya a story. I have a bad gauge, called AEM for a replacement. They said: sure!! But you first must send us a video of you destroying that bad gage. So I didnt get the return because now I want to know whats inside!! I still have it amongst many others in our stock.
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I would share if i come up with something, i have 2 Bosch 6wire, nippon (?) 5wire and shield, and Mitsubishi 6wire, if i remember wich car each is from i probably can look in schematics, and figure out from numbers on the connection socket.
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@ Matt Ryder,
The AEM sensor and signal conditioner are available for a bit less money if the gauge is not needed.
In my case, I can use my Arduino LCD display to show the values.
Here is what the kit without the gauge costs me at the moment… ($234 CAD)
There is also another option…
The controlduino which is an Arduino add-onboard and also comes with the oxygen sensor
These solutions have both been available for some time and the purpose of my question was to find if there have been any new products or developments in this are since 2015.
Based on what I have been able to find, I agree with you that the AEM may still be the best solution.
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Get this one its way cheaper. The white wire on the four wire cable is the lambda out. Its all you need.
Yeah by the time you buy the wideband sensor and that third party card. You are in it for the same cost and the gauge is actually pretty nice. Ive coded it into a GUI but Ive reversed to simpler interfaces. Basically a mode button that can change colors and I can make it send blink codes to tell the user mode of operation, faults etc.
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The problem with these expensive electronics is that it makes it very difficult to keep a spare on hand.
If time get tough, and these electronics are not available, it would be nice to have an alternate method of throttle mix automation. Keeping 3 spare Arduino’s is easy 
Has anyone played with engine vacuum as an indicator of load and gas/air mix ?
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“Get this one its way cheaper. The white wire on the four wire cable is the lambda out. Its all you need.”
Thanks Matt, Actually when you convert to Canadian dollars and add freight, the price is about the same.
That’s what started my search for possible newer alternatives
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Yes there are a number of threads on the vacuum mixers. I have had the Sensors come bad in a the box but I have never seen a new one fail ever.
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So Matt, In the unit that you pointed out it seems the fancy signal conditioning and 0-5v conversion is done inside the gauge housing.
Where do you tap into the 0-5 voltsand ground for the arduino Analog/ground pins?
Just splice into the harness? or perhaps there’s a screw terminal on the back of the gauge that I can’t see?
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Ahhhh … Sorry, I see you made reference to the white Lambda wire.
Thanks.
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The white wire on the four wire cable that plugs into the gage is the 0-5v signal wire
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The Bosch sensors by themselves cost more than a $130 bucks. Thats the expensive part not the gauge or the controller.
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