Oxygen controller

hello, please HELP!!!! I am not a programmer, but I have interesting idea in mind. Please can some one solve for me and make code for this.

So - I took from car lamda sensor (oxygen sensor), and I want to use in this project this oxygen sensor.

Project name - "right gas/air mixture".

in project I need parts:
arduino, rotary encoder, display, stepper, 2 endswiches, lamda sensor, milivolt amplifier (for example x10) and start/stop button.

I have 3 way valve, there I will connect the stepper motor. Valve from min to max is turning from 0 - 90 degree. in this case, the nr.1 inlet is the main gate for the main air flow. when the valve is on 0 degree, than all flow is going through nr.2 output way, and when on 90 degree, than all flow is going through nr. 3 output way, and when is staying on 45 degree, than 50/50 through nr.2 and nr. 3 ways.

endswiches will be mounted on 0 and 90 degree position. Program needs to understand, that motor cant go further by this position, this is limit. To not broke the valve or stepper.

the right air/gas mixture is than, when at the end, the oxygen content is 4-6 %. It means, that lamda sensor will give in the output approx. 6-20 mV. This is small value, so I need to amplifier this output signal, for example by 10 times, so I need to use some amplifier, after that in the output I will receive after amplifier 60-200 mV (for example if I use amp x10), which will be good signal for arduino, I think so.

To work with this device, I need that the stepper moves very very (uber) slow. And the second thing, in menu, I need to give bottom and top values in mV with help of encoder - for example these (Bottom) 60 mV and (Upper) 200 mV. this will save me from situation, that stepper wont work like crazy, if he will be inside these borders, than he wont turn any more, he will stay steady, and, only if there will be some changes in air/gas mixture, only in this situation he will once more start to regulating the valve. (in the menu we can program that these setting range we can change from 20-4500 mV, to have chance to find the right one values)

If some thing is not clear, than please be free and ask me. I can as well draw small sketch.

That sounds like a pretty ambitious project for someone who is not a programmer. If you want to hire someone, post in the "Gigs and Collaborations" forum and pay somebody.

Look up 16 bit adc chips. They can easily read 6-20mV without amplification. There is also one at adafruit that has built in amplification.

If you want your stepper to move extremely slowly, you should look at some gear reduction motors.

good luck

The OP has started a topic for this project in Gigs and Collaborations