Grove_temperature.cpp

00001 
00002 /**
00003  ******************************************************************************
00004  * @file    Grove_temperature.cpp
00005  * @author  Toyomasa Watarai
00006  * @version V1.0.0
00007  * @date    6 Aug 2018
00008  * @brief   Seeed grove temperature sensor class implementation
00009  ******************************************************************************
00010  * @attention
00011  *
00012  * Licensed under the Apache License, Version 2.0 (the "License");
00013  * you may not use this file except in compliance with the License.
00014  * You may obtain a copy of the License at
00015  *
00016  *     http://www.apache.org/licenses/LICENSE-2.0
00017  *
00018  * Unless required by applicable law or agreed to in writing, software
00019  * distributed under the License is distributed on an "AS IS" BASIS,
00020  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00021  * See the License for the specific language governing permissions and
00022  * limitations under the License.
00023  */
00024 
00025 #include "Grove_temperature.h"
00026 
00027 Grove_temperature::Grove_temperature(PinName ain)
00028     : _ain(ain)
00029 {
00030 }
00031 
00032 Grove_temperature::~Grove_temperature()
00033 {
00034 }
00035 
00036 float Grove_temperature::getTemperature()
00037 {
00038     const int B = 4275;               // B value of the thermistor
00039     const int R0 = 100000;            // R0 = 100k
00040 
00041     float R = 1.0f/_ain.read() - 1.0f;
00042     R = R0*R;
00043 
00044     float temperature = 1.0/(log(R/R0)/B+1/298.15)-273.15; // convert to temperature via datasheet
00045     return temperature;
00046 }