![](https://images.ecency.com/DQmP4wb7NHJdTAbVbJEdEdyZ1Zqir6Y8zDn54AaDW3aTKqU/image.png)
Source: [ here](https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.ebay.com.au%2Fitm%2F154495419158&psig=AOvVaw17yMQN0LnEyYH9mN6WZzep&ust=1679551271066000&source=images&cd=vfe&ved=0CBEQjhxqFwoTCOD70p3u7v0CFQAAAAAdAAAAABAL)

Hello everyone community hive, this is Eros (Mike's collab) and today we are going to talk about Lambda Probe. For many people it is a useless sensor, while I, thanks to that sensor solved some carburetion problems in my car.
Since I bought a sizable gauge, a few days ago I asked myself:
Is it possible to build something less bulky, and if so, also integrable into the original dashboard?

Well this was the question that led me to do some research on the internet and find a very simple circuit diagram with 4 electronic components: 1 integrated lc 3914, a voltage regulator, 1 resistor and 10 LEDs.

## Operation

The lambda sensor, nothing more than a meter of oxygen present in the exhaust gas; when the amount of oxygen in the exhaust gas is correct, it means that the ratio of combustion fuel to fuel, is about 14.7:1 (14.7 parts air to 1 part gasoline).
More in detail, this sensor functions based on a chemical reaction that occurs inside the steel liner when certain elements come in contact with the exhaust gas.
Again thanks to this sensor, we can know if our car is running properly and has maximum thermal efficiency.
In addition to having monitored the proper functioning of one's vehicle, we also have the emissions of pollutants under control, in fact, when a gasoline engine runs with the right amount of air/petrol, the exhaust gases are less polluting.

![](https://images.ecency.com/DQmSjpQkUAhf9xiCkEKGWmbgXzbVTpDUuuUDLxQv7Jkwrdn/image.png)
Source: [ Here](https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.bricolageonline.net%2F301%2Ffunzioni-manutenzione-sonda-lambda-auto.htm&psig=AOvVaw0XRM5Xi-jFDwqNixPts7dC&ust=1679551548239000&source=images&cd=vfe&ved=0CBEQjhxqFwoTCMiGwKDv7v0CFQAAAAAdAAAAABAE)

## The purpose

Let's start with the fact that I have a knack for sensing when an engine is not running properly, and I also have a passion for tuning by "ear"; in fact, carburetion (air/fuel ratio) can be done independently by listening to the engine.
When all 4 cylinders get the right amount of fuel, the engine runs even without any holes or uncertainties.

I have had this car for almost 20 years, so as of now it has no more secrets and therefore I proceeded to balance the intake independently by listening to the reactions of the twin-shaft (Alfa Romeo engine).

Unconvinced, however I also resorted to mounting this device to increase the accuracy of the carburetion.
Well, time to order all the components on the internet and off to the mounting of the sensor on the exhaust pipe, connected the 12 v supply to an ignition coil so that the probe is energized only when I turn the key and the instrument cluster comes on.

## The modification

After mounting the sensor to the exhaust pipe and connecting the display, I saw that in addition to being too large, the brightness cannot be adjusted and during night driving it becomes extremely annoying.
So I jumped on the net to retrieve some feasible stuff with the basic tools of an electronics amateur.
This is the schematic I found, note that it is narrowband meaning the signal ranges from a voltage of 0.1 up to 1.1V. The probe, on the other hand, wideband, has a signal that goes from 1 to 5 V; since the range is greater the reading accuracy of this sensor is greater so they are probes that are used only in particularly high-performance or elaborate engines: in these 

a poor mixture of gasoline creates a rise in temperatures that is extremely harmful to the health of the engine.

![](https://images.ecency.com/DQmZVpaUfi1NW9Uf4rhWNaCH1q758ZeJBg6jKicgJ9Kub2F/image.png)
Source: https://fwdmadness.blogspot.com/2015/03/diy-airfuel-ratio-meter.html

Having found the circuit diagram, I ordered all the components on ebay and waited patiently for their arrival.

Arrived, now I set to work!

First I took approximate measurements and cut out the stripboard. 

![](https://images.ecency.com/DQmTUSSKiFmq56rjmRqfdshwPCyuBy56cDMJRYZBHRhFRCy/image.png)
Source: Author

Once the edge irregularities were fixed, I proceeded with mounting the voltage regulator, integrated carrier socket, and resistor

![](https://images.ecency.com/DQmP7JzALZrbtfucTqUs7NRujstdbBZKfzhD3CFHVeQBcXV/image.png)
Source: Author

Having soldered the various components, I inserted the connections and performed the various soldering as shown in the circuit diagram until the final result was obtained:

![](https://images.ecency.com/DQmPkWrhLEeNLFnERFfuhY3yvBPPz5bVM4ZAqBxBjjTUPpm/image.png)
Source: Author

This is the final result of the work.

That's all for this installment, I'll see you at the next one that I test run and implement the whole thing on the dashboard!

See you!