This is update version of my DIY nitrox analyzer based on Arduino compatible board.

It’s using small oled display and powered by 9v battery. Display o2 percentage of gas, sensor mv output, two MOD(maximum operating depth) in meter. 1 push button for lock screen, calibration, po2 change.

Part list
Arduino nano compatible board (or any other Arduino board will do)
ADS1115 16 Bit DAC Module (the ADS1115 provides 16-bit precision at 860 samples/second over I2C!)
0.96 inch OLED 128×64 I2c display module
Rocker or toggle switch for power on/off
1 Push button
1 9v battery connector (better using 3 AA or AAA)
1 Piezo Buzzer (I took one from pc. Skip if you don’t need beeping analyzer :)
1 Connector for o2 sensor (mine is molex)
1 O2 sensor (I use old cell from my CCR but you can get sensor from Teledyne, Maxtec or other manufacturer.”

Link