The output voltage commes from the 2 wires of the sensor and vary from -10mV to 40mV in the range in which I would like to measure the oxygen content in %. So it need amplification and shifting so the all analog signal is positive in order to be readed by Arduino analog input.
Don't waste your time tinkering with amplifiers.
I can't imagine how you're going to calibrate it.
Don't waste your time tinkering with amplifiers.Use an INA226 power monitor module. They cost less than 2$ at your favourite chinese store.They are primary designed to monitor shunts in the range +-80mV. They even can read the mV differential off-rail by up to 36V.Isn't that perfect for your usage?Just unsolder the shunt and read the "mV" directly over the I2C interface.With the Arduino INA library from Zhanshin you get directly a stable and precise mV reading:INA.getShuntMicroVolts(0);Enjoy!
Having all positive voltage output will simplify the design a little. The project looks doable using the circuit posted by johnerrington. But I can't imagine how you're going to calibrate it.S.
I may use MAX6675 for measuring the temperature of flue gas of the boiler. It should not drop less than 120 deg.C to avoid condensation. Do you know better module for K type temperature measurement?
A resistive divider, pot & multimeter to apply voltages?
In that temperature range a PT100 should be the first choice.A max31865 Module should be preferable:https://www.aliexpress.com/item/4000151215433.html