Hi, I am connecting Grove Temp & Hum Sensor to XBee Carrier + Wifi Bee, I am using the library in the Wiki and use the example like this :
[code]// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
#include “DHT.h”
#define DHTPIN 2 // what pin we’re connected to
// Uncomment whatever type you’re using!
#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT22 // DHT 22 (AM2302)
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
// Connect pin 1 (on the left) of the sensor to +5V
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(9600);
Serial.println(“DHTxx test!”);
dht.begin();
}
void loop() {
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds ‘old’ (its a very slow sensor)
float h = dht.readHumidity();
float t = dht.readTemperature();
// check if returns are valid, if they are NaN (not a number) then something went wrong!
if (isnan(t) || isnan(h)) {
Serial.println(“Failed to read from DHT”);
} else {
Serial.print(“Humidity: “);
Serial.print(h);
Serial.print(” %\t”);
Serial.print(“Temperature: “);
Serial.print(t);
Serial.println(” *C”);
}
}[/code]
but the result is :
DHTxx test!
Read failFailed to read from DHT
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
Humidity: 0.00 % Temperature: 0.00 *C
==============
and then I tried to use another code :
[code]/* YourDuino.com Example Software Sketch
DHT11 Humidity and Temperature Sensor test
Credits: Rob Tillaart
http://arduino-direct.com/sunshop/index.php?l=product_detail&p=162
[email protected] */
/-----( Import needed libraries )-----/
#include <dht11.h>
/-----( Declare objects )-----/
dht11 DHT11;
/-----( Declare Constants, Pin Numbers )-----/
#define DHT11PIN 2
void setup() /----( SETUP: RUNS ONCE )----/
{
Serial.begin(9600);
Serial.println("DHT11 TEST PROGRAM ");
Serial.print("LIBRARY VERSION: ");
Serial.println(DHT11LIB_VERSION);
Serial.println();
}/–(end setup )—/
void loop() /----( LOOP: RUNS CONSTANTLY )----/
{
Serial.println("\n");
int chk = DHT11.read(DHT11PIN);
Serial.print("Read sensor: ");
switch (chk)
{
case 0: Serial.println(“OK”); break;
case -1: Serial.println(“Checksum error”); break;
case -2: Serial.println(“Time out error”); break;
default: Serial.println(“Unknown error”); break;
}
Serial.print("Humidity (%): ");
Serial.println((float)DHT11.humidity, 2);
Serial.print("Temperature (oC): ");
Serial.println((float)DHT11.temperature, 2);
Serial.print("Temperature (oF): ");
Serial.println(Fahrenheit(DHT11.temperature), 2);
Serial.print("Temperature (K): ");
Serial.println(Kelvin(DHT11.temperature), 2);
Serial.print("Dew Point (oC): ");
Serial.println(dewPoint(DHT11.temperature, DHT11.humidity));
Serial.print("Dew PointFast (oC): ");
Serial.println(dewPointFast(DHT11.temperature, DHT11.humidity));
delay(2000);
}/* --(end main loop )-- */
/-----( Declare User-written Functions )-----/
//
//Celsius to Fahrenheit conversion
double Fahrenheit(double celsius)
{
return 1.8 * celsius + 32;
}
//Celsius to Kelvin conversion
double Kelvin(double celsius)
{
return celsius + 273.15;
}
// dewPoint function NOAA
// reference: http://wahiduddin.net/calc/density_algorithms.htm
double dewPoint(double celsius, double humidity)
{
double A0= 373.15/(273.15 + celsius);
double SUM = -7.90298 * (A0-1);
SUM += 5.02808 * log10(A0);
SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
SUM += log10(1013.246);
double VP = pow(10, SUM-3) * humidity;
double T = log(VP/0.61078); // temp var
return (241.88 * T) / (17.558-T);
}
// delta max = 0.6544 wrt dewPoint()
// 5x faster than dewPoint()
// reference: http://en.wikipedia.org/wiki/Dew_point
double dewPointFast(double celsius, double humidity)
{
double a = 17.271;
double b = 237.7;
double temp = (a * celsius) / (b + celsius) + log(humidity/100);
double Td = (b * temp) / (a - temp);
return Td;
}
/* ( THE END ) */
[/code]
and the result is :
[code]DHT11 TEST PROGRAM
LIBRARY VERSION: 0.3.2
Read sensor: Time out error
Humidity (%): 0.00
Temperature (oC): 0.00
Temperature (oF): 32.00
Temperature (K): 273.15
Dew Point (oC): nan
Dew PointFast (oC): nan
[/code]
I was wondering that the cause is the I/O pin, in both code above they use pin 2 but when I googling around I found that the code is for DHT11 like this :
pin 1 = VCC
pin 2 = Signal/Data
pin 3 = NC/Not Connected
pin 4 = Ground
not a Grove like I am using :
that’s why the both code use pin 2, so I tried to change it to pin 5 as discribed in Xbee Carrier Wiki, although I am not sure that pin 5 means D5 and pin 6 means D6 Grove Connector:
and when I carefully look at the cable, everything is at the right place :
Cable Colour == Xbee Carrier == Grove Temp Hum
Yellow == D5 == SIG
White == D6 == NC
Red == VCC == VCC
Black == Ground == Ground
but the result is the same, timeout or communication failed, anyone can help?
#sorry for my bad english
