DIY Nitrox Analyzer (Arduino based)

[Saltwater_Parrot]

I've been looking for a new eeng project and just found this. I'm going to look into contributing on this. Looks like He sensors are really expensive otherwise that would've been cool.

 

[LFMarm]

Here is an Arduino based Nitrox anlyzer I recently made. It uses an Arduino Nano, an ADS1115 ADC, and a 0.96" I2C OLED display. It uses the PSR-11-39-JD sensor from DGX. This is loosely based on this one: Arduino oled nitrox analyzer - Eunjae Im. But the code was too complex for me, so I decided to write my own simpler code and display the actual sensor reading in mV as a final check (because I am obsessive about knowing what lies under the hood) .

It auto calibrates at startup and has on-demand calibration via a push-button. I decided not to store calibration values after power off as a safety precaution. It has gone through several iterations and ended up with the sensor and sampler built-in but with an external port. It is powered by an 18650 cell which can be charged via a micro USB port. It uses ~25 mA at full draw.

Included in the pics is one with an external sensor input only and powered by 2 AA batteries and a 5V boost converter and another one using a hacked PM128 panel meter (Oxycheq El Cheapo clone).
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Impressive work. What is the total cost of this setup?

 

[Pao]

Impressive work. What is the total cost of this setup?

Roughly 120 USD when I built it. The bulk of the cost is the O2 sensor @82 USD during the time of the build.

 

[kaiserb]

I just watched your YT video on this device. Looks pretty neat. Thanks for sharing your ideas etc. You may get less expensive sensors if you find someone who uses a rebreather regularly. They change out the sensors in them long before their useful life is finished.