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
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.
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/ 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