reading the SHT75 with the script from bbrack.net is no problem.
Also I would like to read the Temp, Humidity and the dewpoit on a
serial display.
I added the library LiquidCristal in set up nicely printed temp, hum and dewpoint.
But no data is printed on the display.
Can someone help with this topic.
Theo
Well, you could help yourself a bit by posting your sketch.
Dear Groove,
Indeed it will help to enclose the script.
/* werkt met 3 sturen in serial monitor............
/*
/*
#include <ctype.h>
#include <LiquidCrystal.h>
LiquidCrystal lcd(6,7,8,9,10,11,12);
#define DATA 4 /* Arduino pin for data read/write /// aangezet
/ For multiple SHTs, DATA port is given later /
#define CLOCK 2 / Arduino pin for toggling the clock */
#define NOACK 0 /* Flags to tell read_byte routine whether /
#define ACK 1 / or not to send an ACK after the read /
#define ledPin 13 / toegevoegd om te schakelen.
/* Define the SHT1x commands to be their command codes */
#define MEASURE_TEMP 0x03
#define MEASURE_HUMI 0x05
#define STATUS_REG_W 0x06
#define STATUS_REG_R 0x07
#define RESET 0x1e
/* Following constants are in microseconds */
#define LONG_DELAY delayMicroseconds(80)
#define MEDIUM_DELAY delayMicroseconds(40)
#define SHORT_DELAY delayMicroseconds(20)
unsigned char debug; /* When set, intermediate data is printed */
/**
pinMode (dataport, OUTPUT);
for (ix = 0x80; ix; ix >>= 1) {
digitalWrite (dataport, ix & value);/* Next bit to I/O port /
SHORT_DELAY; / Shouldn't be needed /
digitalWrite (CLOCK, HIGH); / Set clock signal high /
MEDIUM_DELAY; / some delay needed /
digitalWrite (CLOCK, LOW); / Set clock back to low /
}
pinMode (dataport, INPUT); / Prepare to read the ACK bit /
digitalWrite (dataport, HIGH); / Engage pull-up resistor /
digitalWrite (CLOCK, HIGH); / Send 9th clock for ack) /
//SHORT_DELAY;
MEDIUM_DELAY;
error = digitalRead (dataport); / Expect pulled down by SHT1x /
SHORT_DELAY;
digitalWrite (CLOCK, LOW); / complete the clock pulse */
return error;
}
/**
/*
for (ix = 0x80; ix; ix >>= 1) {
digitalWrite (CLOCK, HIGH); /* High tells SHT75 we're reading /
SHORT_DELAY;
if (digitalRead (dataport))
val |= ix; / If DATA high, set corr. bit /
digitalWrite (CLOCK, LOW); / Tell SHT75 ready for next bit /
SHORT_DELAY;
}
pinMode (dataport, OUTPUT); / Change mode to prepare for ack /
digitalWrite (dataport, !sendAck); / Set DATA LOW if sendAck requested /
digitalWrite (CLOCK, HIGH); / Let SHT75 get the data /
MEDIUM_DELAY; / delay for safety /
digitalWrite (CLOCK, LOW); / Signal we're done with this /
SHORT_DELAY;
pinMode (dataport, INPUT); / Return Arduino pin to input /
digitalWrite (dataport, HIGH); / And engage the pull-up */
return val;
}
/**
pinMode (dataport, INPUT);
digitalWrite (dataport, HIGH);
}
/**
/**
/**
for (ix = 0; ix < 8; ix++) {
b7 = ch ^ *crc;
*crc <<= 1;
ch <<= 1;
if (b7 & 0x80)
*crc ^= CRC_POLY;
}
return;
}
/**
Dear Groove,
As the script is to large for one post i have to post it at maybe three posts.
sec. one
char sMeasure (unsigned char pValue, unsigned char command,
unsigned char singleFlag, unsigned int dataport)
{
unsigned char error; / holds return value from routine /
unsigned int ix; / used for 'wait for data' loop */
unsigned char ch, crc, revCRC;
crc = 0; /* Initialize CRC to zero /
sTransmitStart (dataport); / Start transmission of command /
error = sWriteByte (command, dataport); / Send the requested command /
/ Note that sWriteByte leaves DATA in input mode /
doCRC (command, &crc); / Include command in CRC /
if (debug) {
Serial.print("After 'command': CRC is 0x");
Serial.println(crc, HEX);
}
for (ix = 0; ix < 240; ix++){
delay(1); / This delay is needed for long cables /
if (!digitalRead (dataport))
break;
}
if (digitalRead (dataport))
Serial.println("DATA did not go low after writing command");
if (!singleFlag) { / If a 2-byte reply /
ch = sReadByte (ACK, dataport); / Read MSB of data /
doCRC (ch, &crc); / Include in CRC */
if (debug) {
Serial.print("After MSB: CRC is 0x");
Serial.println(crc, HEX);
}
(pValue + 1) = ch; / Store MSB byte /
}
ch = sReadByte (ACK, dataport); / Read LSB of data /
doCRC (ch, &crc); / Include in CRC */
pValue = ch; / Store LSB byte /
if (debug) {
Serial.print("After LSB: CRC is 0x");
Serial.println(crc, HEX);
}
ch = sReadByte (NOACK, dataport); / Read msg CRC, don't send ACK */
revCRC = 0;
for (ix = 0; ix < 8; ix++) {
if ((0x80 >> ix) & ch)
revCRC |= (1 << ix);
}
if (debug) {
Serial.print("After Checksum: CRC is 0x");
Serial.print(crc, HEX);
Serial.print(", received value was 0x");
Serial.println(revCRC, HEX);
}
if (crc != revCRC) {
Serial.print("CRC error in reply (command was 0x");
Serial.print(command, HEX);
Serial.print("CRC is 0x");
Serial.print(crc, HEX);
Serial.print(", received value was 0x");
Serial.println(revCRC, HEX);
Serial.println(") - resetting SHT1x connection");
sConnectionReset(dataport);
}
return error;
}
/**
float rh = pHumidity; / relative humidity (input value) /
float rhLin; / Linear value of humidity /
float rhTrue; / Temperature-compensated humidity value */
float t = pTemperature; / input value for temperature /
float tC; / Temperature converted to Celsius */
tC = D1 + (t * D2); /* Linear conversion of temperature /
rhLin = (C3 * rh * rh) + (C2 * rh) + C1; / "ticks" to relative H /
rhTrue = (tC - 25) * (T1 + (T2 * rh)) + rhLin;
/ Assure our relative humidity isn't out of range (> 100% or < 0.1%) /
if (rhTrue > 100.0)
rhTrue = 100.0;
else if (rhTrue < 0.1)
rhTrue = 0.1;
/ Finally, return the calculated values */
*pTemperature = tC;
*pHumidity = rhTrue;
}
/**
/**
int ix;
int frac;
float fVal;
/* Round the input according to precision, plus fudge for noise */
fVal = *fNum + (0.5 * pow(10.0, (float)(-decPlaces))) + 0.00001;
pInt = fVal; / Return truncated integer value /
/
/**
splitFloat (pVal, &num, str, 2);
Serial.print(label);
Serial.print(num, DEC);
Serial.print(".");
Serial.print(str);
Serial.println(suffix);
}
/**
Serial.begin(4800); /* Open Arduino serial communications was 9600 veranderd dus */
pinMode (CLOCK, OUTPUT);
pinMode (DATA, OUTPUT); // aan gezet
for (int i = 3; i < 10; i++){
sConnectionReset(i);
}
Serial.println("Acceptable commands:");
Serial.println("d or D: Toggle debug flag for printing intermediate data");
Serial.println("s or S: Read status register");
Serial.println("3 - 9 : Read in temperature and humidity\n");
}
void loop()
{
char cmd; /* command input by user /
int humidVal; / humidity value read from SHT75 /
int tempVal; / temperature value from SHT75 /
unsigned char statusVal; / contents of status register /
float fHumidity; / working value for humidity calculation /
float fTemperature; / working value for temperature calculation /
float dewPoint; / calculated Dew Point value /
unsigned char error; / return value for routi
Dear Grooove,
It will do in three posts.
the third one.
More explanation:
I already added the LiquidDisplay library.
Programmed the tempereture:
Vochtigheid:
Dewpoint:
So far ok. But if i am program lcd.print (fTemperature,DEC); it will not apear on the display. However the ledpin is working on fTemperature.
What I would like to achieve is real time reading temp, hum, and dewp on the display.
unsigned int port;
while (Serial.available() > 0) { /* when a serial connection exists /
cmd = Serial.read(); / Read user comand /
error = 0;
if (isdigit(cmd)) {
port = atoi(&cmd);
if (port < 2) {
Serial.println("Unable to access serial communication port!\n");
break;
}
if (port == CLOCK) {
Serial.println("Unable to access SHT-xx CLOCK port!\n");
break;
}
/ Read request - read in temperature and humidity */
Serial.print("Accessing port ");
Serial.println(port);
error += sMeasure ((unsigned char *)&humidVal, MEASURE_HUMI, 0, port);
if (debug) {
Serial.print("In main loop: humidVal is ");
Serial.print(humidVal, HEX);
Serial.print(" and return value is ");
Serial.println(error, DEC);
}
error += sMeasure ((unsigned char *)&tempVal, MEASURE_TEMP, 0, port);
if (debug) {
Serial.print("In main loop: tempVal is ");
Serial.print(tempVal, HEX);
Serial.print(" and return value is ");
Serial.println(error, DEC);
}
if (error)
sConnectionReset(port);
else {
fHumidity = float(humidVal);
fTemperature = float(tempVal);
calcTempHumid (&fHumidity, &fTemperature);
dewPoint = calcDewPoint (fHumidity, fTemperature);
//printReading ("Temperature is ", &fTemperature, "\xb0 Celsius");
printReading ("Temperatuur is ", &fTemperature, " degrees Celsius");
printReading ("Vochtigheid is ", &fHumidity, "%");
//printReading ("Dauw punt is ", &dewPoint, "\xb0 Celsius");
printReading ("Dauw punt is ", &dewPoint, " degrees Celsius");
if (fTemperature > 20.89) { // toegevoegd om te schakelen
digitalWrite ( ledPin,HIGH);
}else{
digitalWrite( ledPin,LOW); // toegevoegd om te schakelen
}
}
Serial.println();
break;
}
switch (cmd) {
case 'd': /* "Toggle" debug flag for printing /
case 'D': / intermediate data /
debug ^= 1;
if (debug)
Serial.println("*** Debugging enabled ");
else
Serial.println(" Debugging disabled ***");
break;
case 's': / Read status register /
case 'S':
Serial.println("Read status register. Input a port number:");
while(1) {
cmd = Serial.read(); / Read user comand /
if (isdigit(cmd)) {
port = atoi(&cmd);
if (port < 2) {
Serial.println("Unable to access Serial port!\n");
break;
}
if (port == CLOCK) {
Serial.println("Unable to access CLOCK port!\n");
break;
}
Serial.print("Accessing port ");
Serial.println(port);
/ Read request - read in temperature and humidity */
error += sMeasure ((unsigned char *)&statusVal, STATUS_REG_R, 1, port);
Serial.print("Status register contains 0x");
Serial.println(statusVal, HEX);
Serial.println();
break;
}
}
break;
default:
Serial.println("Unrecognized command.");
}
}
}
For those who are interrested in reading sht data serial as well as on LCD here my code for the LCD part.
First include the liquidCrystal.h lib in your script.
Then the LCD i/o pins
I introduced a selector switch serial or LCD
If LCD use the code
}else{
port=5; // leest de data uit ARDUINO data port
digitalWrite(lcdLed,HIGH); // keuze switch op lcd als led aan is.
sMeasure ((unsigned char *)&tempVal, MEASURE_TEMP, 0, port); // leest de temp waarde grof uit de SHT
sMeasure ((unsigned char *)&humidVal, MEASURE_HUMI, 0, port); // pas op op deze stand warmt sht op kennelijk door verwarming calibratie.??????????
fTemperature = float(tempVal); // ruwe SHT temp waarde omzetten naar float
Temperature=(fTemperature/100)-40,561; // ruwe waarde naar werkelijke waarde omrekenen.
fHumidity = float(humidVal); // ruwe SHT humid waarde omzetten naar float
Humidity=(((fHumidity * fHumidity * -28) / 10000000)+((fHumidity * 4)/100))-4; // ruwe waarde omrekenen naar werkelijke waarde
logEx = 0.66077 + (7.5 * Temperature) / (237.3 + Temperature) + (log10(Humidity) - 2); // dauw punt berekenen uit temp en humid.
Dauwpunt= (logEx - 0.66077) * 237.3 / (0.66077 + 7.5 - logEx);
lcd.setCursor(9,0); // print to lCD
lcd.print(Temperature);
lcd.setCursor(9,1);
lcd.print(Humidity);
lcd.setCursor(6,2);
lcd.print(Dauwpunt);
lcd.setCursor(6,3);
lcd.print("on LCD");
if (Temperature < 18.89) { // toegevoegd om te schakelen
digitalWrite ( ledPin,HIGH);
}else{
digitalWrite( ledPin,LOW); // toegevoegd om te schakelen
}
}
} 
Hopefully it is of interesr for someone.
Theo
Misschien een idee om je posts te veranderen (rechts van je post "modify") door # te gebruiken.
Selecteer je code en klik op #. Het word niet op prijs gesteld om code zo te posten.
Jeroen
hinted the use of #
Note to solution reading also on display.
After you read the measurements on port #5
you must switch off port #5 again and delay a moment.
All according the SHT data sheet point 3 while continous power on gives incorrect readings.
Theo
Jeroen,
Bedankt voor de tip.
Ik heb vlug even de help gelezen en er is veel
te doen om een juiste post te maken plaatsen.
Theo