He also added an ADS1115 16 Bit DAC between the oxygen sensor and the Arduino for fast and accurate readings over I2C. With the hardware assembled, ...

He also added an ADS1115 16 Bit DAC between the oxygen sensor and the Arduino for fast and accurate readings over I2C. ... The oxygen sensor, however, was clearly in need of attention.

The microcontroller-based concept was chosen because I wanted to scale the sensor system later to suit other applications. Here is the diagram of my Arduino infrared close proximity sensor. As you can ...