Hello all,
i like to have a normalization of the pressure value of the BMP180. Formula is:
pressure / pow(1.0 - altitude/44330.0, 5.255)
How do I do this with a rule and variable?? Especially with the complex formula?
Thanks
pressure normalization of BMP180
Hello all,
i like to have a normalization of the pressure value of the BMP180. Formula is:
pressure / pow(1.0 - altitude/44330.0, 5.255)
How do I do this with a rule and variable?? Especially with the complex formula?
Thanks
It will be possible with the next release (which will be available shortly).
Here is a proof of concept:
"variables": [
{
"name": "pressure",
"value": 1024
},
{
"name": "altitude",
"value": 500
},
{
"name": "normalizedPressure",
"expression": "$pressure/pow(1.0-$altitude/44330.0,5.255)"
}
]
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
Nice to read
@temp released pimatic@0.9.35
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
I linke to use this Formula
'pressure*(1-((0.0065*altitude)/(21+0.0065*altitude+237.15)))**(-5.257)'
because it is more accurate but it always display expression error…
Why? Whats wrong?
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
@mwittig said in pressure normalization of BMP180:
@temp said in pressure normalization of BMP180:
**
What is
**
? pow()?
Yes, See also keisan.Casio.com/exec/system/1224575267
@temp The following works for me, but I am not sure this what is intended:
$pressure*pow((1-((0.0065*$altitude)/(21+0.0065*$altitude+237.15))),-5.257)
The result is 1093 dot something for the values I had in the previous example
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
@temp said in pressure normalization of BMP180:
237.15
I think think this should be 273,15 for 0 deg C
EDIT: Just checked my result against the online calc which looks OK. Corrected expression:
$pressure*pow((1-((0.0065*$altitude)/(21+0.0065*$altitude+273.15))),-5.257)
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
@mwittig thanks