Trimix analyser

Most important thing you have to know about our Trimix Analyser ...

The most important thing you have to know is that we are divers and we don't want to use a black box made by a company. Whe want to UNDERSTAND the system and we want to be able to OPEN and AUDIT it. We can't trust something not transparent, that's all !

Open source and Open hardware are essential to establish our trust relation. For hardware everything is not as open as whe would like ... but we do our maximum to use as open as possible hardware.

There are some divers who made "do it youself" trimix analiser, for example:

• http://www.ufp-plongee.com/forum/viewtopic.php?f=9&t=18672
• https://github.com/captainigloo/Trimix-analyzer (be carefull this project is cc-by-nc-sa)
• http://aspttlyonplongee.free.fr/matos/stick_oxyettrimix_arduino.pdf

MD62 or Sound speed ?

Most of "do it yourself" trimix analyser uses MD62 component to analyse gas ... we would like to build a system based on sound speed but as usual we are open minded and our trixmix analyser could be based on MD62 or sound-speed ... or maybe MD AND sound-speed ... that is a big step from our crowdfunding campaing.

A do-it-yourself Trimix Analyser

Here is the list of furniture you need to set up your free Trimix Analyzer:

• used O2 sensor from your CCR or from a friend :-)
• power switch 0.5€ french e44 store | amazon
• 9v battery connector 1,5€ french e44 store | amazon
• Arduino Nano 21€ french generation robot store | amazon
• ADS 1115 15€ french generation robot store | amazon
• oled screen 0'96 128x64 15€ conrad store | amazon
• A Molex connector or a jack connector or ... (it depends on your 02 sensor)
• Some of electric wire
• A soldering kit
• A PCB : an experimental one or a GasBlender.org one :)
• .../... (this list is not enought)

A ready to use PCB from Gasblender.org (nitrox based)

You have the same part, yes if you start with a nitrox analyser you could extend it later to a trimix like us ! Or you can get spare parts from one nitrox to a trixmix and vice et versa !

A ready to use PCB to add trimix stuff to nitrox based one

We have to add some sensors for trimix analyser:

• temperature
• humidity
• sound speed component
• or md62 as alternative

A ready to use sound speed analyser electronic component from Gasblender.org

This part is a important step from our crowdfunding campaign ! Please help us to convert this idea to a real electronic object you can plug into your system !

A ready to print 3D case from Gasblender.org

This one is "easy" but have to be done after the PCB design and the sound-speed part to get the right size !

Our first "proof of concept" prototype

For the moment our first proof of concept is really ... a concept :) design in a paper box as you can see

Then we put everything into a plastic bag and make it as "air proof" as possible to avoid helium leak:

And we make some tests, with air our sound-speed get results near than 295 - 288 (our code does not yet use average compute algorithm) :

Then we put some helium mix (i just have a 17/36 gax mix for this tests) ... and "yahoo" sound speed is not the same :-)

So this is enought to image a good solution with a relative cheap electronic component ... then please support us and participate to our crowdfunding campaign :-)