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grovetemp: updated conversion formula for v1.2 compatibility

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Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>
This commit is contained in:
Mihai Tudor Panu
2016-08-02 10:16:46 -07:00
parent 84a77730be
commit bda66a3d06
2 changed files with 19 additions and 6 deletions
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8
src/grove/grovetemp.cxx
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@@ -33,7 +33,7 @@
using namespace upm;
GroveTemp::GroveTemp(unsigned int pin, float scale)
GroveTemp::GroveTemp(unsigned int pin, float scale, int r0, int b)
{
if ( !(m_aio = mraa_aio_init(pin)) ) {
throw std::invalid_argument(std::string(__FUNCTION__) +
@@ -42,6 +42,8 @@ GroveTemp::GroveTemp(unsigned int pin, float scale)
}
m_name = "Temperature Sensor";
m_scale = scale;
m_r0 = r0;
m_b = b;
}
GroveTemp::~GroveTemp()
@@ -55,8 +57,8 @@ int GroveTemp::value ()
if (a == -1.0) return -1;
// Apply scale factor after error check
a *= m_scale;
float r = (float)(1023.0-a)*10000.0/a;
float t = 1.0/(log(r/10000.0)/3975.0 + 1.0/298.15)-273.15;
float r = (float)(1023.0-a)*(float)m_r0/a;
float t = 1.0/(log(r/(float)m_r0)/(float)m_b + 1.0/298.15)-273.15;
return (int) round(t);
}