gas-blending's Introduction

Welcome to DiveTools Gas Blending

This tool is for testing and educational use.

It is not intended to confirm the mix of breathing gases. If this tool is used a separate test is needed with an appropriate and calibrated and tested O2 and He sensor.

This tool will provide information for mixing Air, O2, and He with a SCUBA compressor. The intended use is to have two O2 sensors that are able to calculate a mix before it goes into a compressor. Two "Nitrox" sticks are used in series. One to mix in He and one to mix in O2. The tool can also be used as a nitrox analyser.

To Install this tool:

Install latest Raspberry Pi OS with desktop.(2021-05-07-raspios-buster-armhf.img Tested)
Under Raspberry Pi Configuration --> Interfaces --> Enable "I2C"
pip install Adafruit_ADS1x15
sudo apt-get install python3-tk
git clone git://github.com/divetools/Gas-Blending.git
ln -s ~/Gas-Blending/HEALTH.desktop ~/Desktop/HEALTH.desktop
Open File Manager --> Select Edit --> Preferences --> General Tick the option "Don't ask options on launch executable file"

Wire up an Adafruit ADS1115 to the pi I2C GPIOs. Connect two O2 sensors to port 0 and 1 on the ADS.

Hardware Components:

2021 Update - In an effort to reduce cost, I designed a new hardware case for the project. This case is 3D printed and will reduce the cost of the project. The STL's can be found at https://www.thingiverse.com/thing:4892104 for download and printing.

Part Name	QTY	Price	Link
Raspberry Pi 3 B+ Motherboard	1	$55.96	Amazon
Raspberry Pi 3 Power Supply 5V 2.5A	1	$9.99	Amazon
HiLetgo ADS1115 16 Bit	1	$6.99	Amazon
Micro SD Flash Drive	1	$13.89	Amazon
Raspberry Pi Official 7 Inch Touch Screen	1	$69.99	Amazon
3.5mm Stereo Jack	4	$3.20	Amazon
Total:	$160.02