SmartD / Mbed 2 deprecated mbed_pH_test

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Dependencies:   mbed

Fork of mbed_pH225 by SmartD

main.cpp@0:f610f2c606a8, 2015-02-18 (annotated)

Committer:
sitakumar
Date:
Wed Feb 18 05:18:56 2015 +0000
Revision:
0:f610f2c606a8
Child:
1:843151144560
2/17

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sitakumar 0:f610f2c606a8 1 #include "mbed.h"
sitakumar 0:f610f2c606a8 2 #include "time.h"
sitakumar 0:f610f2c606a8 3
sitakumar 0:f610f2c606a8 4 DigitalOut myled(LED1);
sitakumar 0:f610f2c606a8 5 //serial connection via USB
sitakumar 0:f610f2c606a8 6 Serial pc(USBTX, USBRX);
sitakumar 0:f610f2c606a8 7 AnalogIn pH_sensor(A0);
sitakumar 0:f610f2c606a8 8
sitakumar 0:f610f2c606a8 9 int main()
sitakumar 0:f610f2c606a8 10 {
sitakumar 0:f610f2c606a8 11 float voltage, pH, tempC, tempF;
sitakumar 0:f610f2c606a8 12
sitakumar 0:f610f2c606a8 13 while(1) {
sitakumar 0:f610f2c606a8 14 double totalVal = 0.0;
sitakumar 0:f610f2c606a8 15 double pH_sensor_read = 0.0;
sitakumar 0:f610f2c606a8 16 int totalReadings = 0;
sitakumar 0:f610f2c606a8 17 time_t start = time(NULL);
sitakumar 0:f610f2c606a8 18 time_t seconds = 10;
sitakumar 0:f610f2c606a8 19 time_t end = start + seconds;
sitakumar 0:f610f2c606a8 20 while(time(NULL) < end){
sitakumar 0:f610f2c606a8 21 pH_sensor_read = pH_sensor.read();
sitakumar 0:f610f2c606a8 22 totalVal = totalVal + pH_sensor_read;
sitakumar 0:f610f2c606a8 23 totalReadings++;
sitakumar 0:f610f2c606a8 24 }
sitakumar 0:f610f2c606a8 25 double avgSensor = totalVal/(double)totalReadings;
sitakumar 0:f610f2c606a8 26 //hard coded calibration values taken at pH 4 solution to return voltage in mV
sitakumar 0:f610f2c606a8 27 voltage = avgSensor*(800/.24);
sitakumar 0:f610f2c606a8 28 //conversion to pH from sensor output voltage per LM61 data sheet
sitakumar 0:f610f2c606a8 29 pH = (0.0209*voltage)-12.696;
sitakumar 0:f610f2c606a8 30 //conversion to degrees C from sensor output voltage
sitakumar 0:f610f2c606a8 31 tempC = (((voltage/1000) - 0.871481)/-0.0021504);
sitakumar 0:f610f2c606a8 32 tempF = (tempC *9/5) + 32;
sitakumar 0:f610f2c606a8 33 //print current pH and temp
sitakumar 0:f610f2c606a8 34 pc.printf("pH = %5.2F & temp = %5.2F F\n\r", pH, tempF);
sitakumar 0:f610f2c606a8 35 }
sitakumar 0:f610f2c606a8 36 }