2017-06-25, 05:56 PM
I am working with induction water sensors to monitor the water (not clear if these sensors works for hydrocarbons, most probably not) level in tanks.
For background see my project page about Tank levels. The sensors produce a simple on/off signal, e.g. they fire when they sense water behind the pipe or tank wall, glass of metal works ok. A set of sensors are needed, using 4 one could have 0.0, 0.25, 0.5, 0.75 and 1.0. The exact numbers would depend on where the sensors are places. With clever measurement and math one might even manage to get correct numbers for a irregular shaped tank. Either by placing the sensors at the precalculated heights of via some math in the function. The latter is a bit hard as it might be that 3 of 4 sensors would fire at only 1/2 full tank. It should be best to place the sensors smart.
As there are a limited set of on/off IO pins on the Pi itself I propose to use some external IO boards over the I2C bus which can bring the possible on/off IO pins up to 128. How this is done is documented on my project page. It's actually quite simple.
Using a set of these sensors I plan to write a function that return a float number from 0.0 to 1.0 which correspond to a meter type widget in the Signal K web page. Hence the tank level would be mapped and displayed quite nicely. The only part I'm not really certain about is how to generate new Signal K names and exactly how I should integrate this function into the OpenPlotter structure, some help and cooperation with this would be nice.
For background see my project page about Tank levels. The sensors produce a simple on/off signal, e.g. they fire when they sense water behind the pipe or tank wall, glass of metal works ok. A set of sensors are needed, using 4 one could have 0.0, 0.25, 0.5, 0.75 and 1.0. The exact numbers would depend on where the sensors are places. With clever measurement and math one might even manage to get correct numbers for a irregular shaped tank. Either by placing the sensors at the precalculated heights of via some math in the function. The latter is a bit hard as it might be that 3 of 4 sensors would fire at only 1/2 full tank. It should be best to place the sensors smart.
As there are a limited set of on/off IO pins on the Pi itself I propose to use some external IO boards over the I2C bus which can bring the possible on/off IO pins up to 128. How this is done is documented on my project page. It's actually quite simple.
Using a set of these sensors I plan to write a function that return a float number from 0.0 to 1.0 which correspond to a meter type widget in the Signal K web page. Hence the tank level would be mapped and displayed quite nicely. The only part I'm not really certain about is how to generate new Signal K names and exactly how I should integrate this function into the OpenPlotter structure, some help and cooperation with this would be nice.
Ole W. Saastad
web : https://www.homelinux.no https://algol.homelinux.no
https://github.com/olewsaa/Yacht-computer
twitter : olewsaa
web : https://www.homelinux.no https://algol.homelinux.no
https://github.com/olewsaa/Yacht-computer
twitter : olewsaa