Trimix Analyser

updated version:

https://www.printables.com/model/677331-trimix-analyser-v2

This is my housing and sensor tube to go with the electronics of the trimix analyser.

The housing is as compact as I could make it around the electronics and components.

The analyser functions surprisingly well. The differences to the Divesoft analyser that uses a different technology is within the measurement error of 1%, both for the oxygen as well as the helium content.

Biggest plus for me, is that this analyser is not sensitive to noise (as the Divesoft is) I can use it in the intake of my compressor (fed by a small pump) after my Trimix-Stick and double check what is going through the compressor, not having to rely only on the two oxygen sensors of the TMX stick

Part-List:

Housing:

• Front
• Back
• Button (to access the battery module, not strictly necessary)
• Sensor tube

Electronics:

(Links are examples)

• O2 Sensor (https://www.aliexpress.com/item/4001251139449.html?spm=a2g0s.8937460.0.0.10c32e0e4awVNS)
• “He” Sensor MD62(https://www.aliexpress.com/item/32725880118.html?spm=a2g0o.9042311.0.0.27424c4djdDbgC)
• Microcontroller Seeeduino (https://www.aliexpress.com/item/1005001728616918.html?spm=a2g0o.9042311.0.0.27424c4d7wiisY)
• 16bit ADC ADS1115 (https://www.aliexpress.com/item/32850495005.html?spm=a2g0o.9042311.0.0.27424c4dLEGYza)
• Display (https://www.aliexpress.com/item/32844104782.html?spm=a2g0o.9042311.0.0.27424c4dkFcJHs)
• LiPo charger board (https://www.aliexpress.com/item/1005002265364454.html?spm=a2g0o.9042311.0.0.27424c4dCHGMHp)
• Voltage regulator LM317
• Resistors
• Trim potentiometers 1kOhm

The circuit board was done in Fritzing

Idea & Arduino code is largely based on these two projects (adapted to my components and preferences):

https://github.com/captainigloo/Trimix-analyzer

https://www.godive-brandenburg.de/downloadse2467a8c