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Arduino Uno code for H2S sensor from SPEC Sensors
// SPEC H2S Sensor
// See https://electronza.com/h2s-sensing-revisited-tutorial-arduino-uno/
// Serial number of my sensor
// #define mysensor_serial_no 012017030207
// #define portOne_RX_BUFFER_SIZE 256
// #define portOne_TX_BUFFER_SIZE 256
// Sensor values
// The format of the output is: SN[XXXXXXXXXXXX], PPB [0 : 999999], TEMP [-99:99],
// RH[0:99], RawSensor[ADCCount], TempDigital, RHDigital, Day[0:99], Hour [0:23]
// Note that on Arduino Due integer variable (int) stores a 32-bit (4-byte) value.
// This yields a range of -2,147,483,648 to 2,147,483,647
// (minimum value of -2^31 and a maximum value of (2^31) - 1).
// On 8 bit boards some readings have to be recorded as floats
// The big change: we use software serial for H2S sensor
#include <SoftwareSerial.h>
// software serial #1: RX = digital pin 10, TX = digital pin 11
SoftwareSerial portOne(10, 11);
String SensorSerialNo;
long H2S;
long Temperature;
long RH;
long RawSensor;
long TempDigital;
long RHDigital;
int Days;
int Hours;
int Minutes;
int Seconds;
#define command_delay 500
#define start_delay 2500
String dataString = "";
String responseString = "";
boolean dataStringComplete = 0;
char inChar;
void setup() {
Serial.begin(9600);
Serial.println("H2S sensor demo code!");
portOne.begin(9600);
// Normally, data is returned within one second
portOne.setTimeout(1000);
// reserve 80 bytes for the dataString
dataString.reserve(150);
responseString.reserve(150);
// Wait for sensor
delay(500);
flush_portOne();
// EEPROM dump
SPEC_dump_EEPROM();
Serial.println(" ");
Serial.println("STARTING MEASUREMENTS");
Serial.println(" ");
}
void loop() {
// Do a readout every 10 seconds
SPEC_Data_read();
SPEC_parse_data();
SPEC_print_data();
delay(10000);
}
/* ********************************************************************************
* This function triggers one measurement and receives the data from the sensor
**********************************************************************************/
void SPEC_Data_read(){
// First, we do some initialization
// dataStringComplete is set as "false", as we don't have any valid data received
dataStringComplete = 0;
// Clear the data string
dataString = "";
// Now we trigger a measurement
portOne.print(" ");
// We wait for the sensor to respond
dataString = portOne.readStringUntil('\n');
//Serial.println(dataString);
}
/* ********************************************************************************
* This function takes the received string and upodates sensor data
**********************************************************************************/
void SPEC_parse_data(){
// Parses the received dataString
// Data string is comma separated
// The format of the output is: SN[XXXXXXXXXXXX], PPB [0 : 999999], TEMP [-99:99],
// RH[0:99], RawSensor[ADCCount], TempDigital, RHDigital, Day[0:99], Hour [0:23],
// Minute[0:59], Second[0 : 59]\r\n
// Take a look also at
// https://stackoverflow.com/questions/11068450/arduino-c-language-parsing-string-with-delimiter-input-through-serial-interfa
// We look first for the SN
int idx1 = dataString.indexOf(',');
SensorSerialNo = dataString.substring(0, idx1);
int idx2 = dataString.indexOf(',', idx1 + 1);
// Hint: after comma there's a space - it should be ignored
String S_gas = dataString.substring(idx1 + 2, idx2);
H2S = S_gas.toInt();
int idx3 = dataString.indexOf(',', idx2 + 1);
String S_temp = dataString.substring(idx2 + 2, idx3);
Temperature = S_temp.toInt();
int idx4 = dataString.indexOf(',', idx3 + 1);
String S_humi = dataString.substring(idx3 + 2, idx4);
RH = S_humi.toInt();
int idx5 = dataString.indexOf(',', idx4 + 1);
String S_raw_gas = dataString.substring(idx4 + 2, idx5);
RawSensor = S_raw_gas.toInt();
int idx6 = dataString.indexOf(',', idx5 + 1);
String S_Tdigital = dataString.substring(idx5 + 2, idx6);
TempDigital = S_Tdigital.toInt();
int idx7 = dataString.indexOf(',', idx6 + 1);
String S_RHdigital = dataString.substring(idx6 + 2, idx7);
RHDigital = S_RHdigital.toInt();
int idx8 = dataString.indexOf(',', idx7 + 1);
String S_Days = dataString.substring(idx7 + 2, idx8);
Days = S_Days.toInt();
int idx9 = dataString.indexOf(',', idx8 + 1);
String S_Hours = dataString.substring(idx8 + 2, idx9);
Hours = S_Hours.toInt();
int idx10 = dataString.indexOf(',', idx9 + 1);
String S_Minutes = dataString.substring(idx9 + 2, idx10);
Minutes = S_Minutes.toInt();
int idx11 = dataString.indexOf('\r');
String S_Seconds = dataString.substring(idx10 + 2, idx11);
Seconds = S_Seconds.toInt();
}
/* ********************************************************************************
* This function prints the sensor data
**********************************************************************************/
void SPEC_print_data(){
Serial.println("********************************************************************");
Serial.print ("Sensor Serial No. is ");
Serial.println (SensorSerialNo);
Serial.print ("H2S level is ");
Serial.print (H2S);
Serial.println (" ppb");
Serial.print ("Temperature is ");
Serial.print (Temperature, DEC);
Serial.println (" deg C");
Serial.print ("Humidity is ");
Serial.print (RH, DEC);
Serial.println ("% RH");
Serial.print ("Sensor is online since: ");
Serial.print (Days, DEC);
Serial.print (" days, ");
Serial.print (Hours, DEC);
Serial.print (" hours, ");
Serial.print (Minutes, DEC);
Serial.print (" minutes, ");
Serial.print (Seconds, DEC);
Serial.println (" seconds");
Serial.println ("Raw Sensor Data");
Serial.print ("Raw gas level: ");
Serial.println (RawSensor);
Serial.print ("Temperature digital: ");
Serial.println (TempDigital);
Serial.print ("Humidity digital: ");
Serial.println (RHDigital);
Serial.println ("");
}
/* ********************************************************************************
* EEPROM dump
**********************************************************************************/
void SPEC_dump_EEPROM(){
// First we trigger a measurement
portOne.print(" ");
// Within one second time we send the command "e"
delay(400);
portOne.print("e");
dataString = portOne.readStringUntil('\n');
// You can uncomment this line if you wish
//Serial.println(dataString);
for (int i=0; i<20; i++){
responseString = portOne.readStringUntil('\n');
Serial.println(responseString);
}
}
void flush_portOne(){
// Do we have data in the serial buffer?
// If so, flush it
if (portOne.available() > 0){
Serial.println ("Flushing serial buffer...");
while(1){
inChar = (char)portOne.read();
delay(10);
Serial.print(inChar);
if (inChar == '\n') break;
}
Serial.println (" ");
Serial.println ("Buffer flushed!");
}
}
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