Estoy tratando de leer datos de temperatura de un sensor de temperatura DHT11, usando pi4j. Seguí el código escrito en cy python en este sitio:http://www.uugear.com/portfolio/dht11-h ... o-module / Pero no funciona. cuando pruebo la instrucción 'dht11Pin.getState ()' siempre está en estado ALTO, nunca cambia. ¿Hay algo mal en mi código?

Abajo está mi código:

import java.util.concurrent.TimeUnit;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import com.pi4j.component.ObserveableComponentBase;
import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinDigitalMultipurpose;
import com.pi4j.io.gpio.Pin;
import com.pi4j.io.gpio.PinMode;
import com.pi4j.io.gpio.PinPullResistance;
import com.pi4j.io.gpio.PinState;
import com.pi4j.io.gpio.RaspiPin;

public class DHT11 extends ObserveableComponentBase {

private static final Pin DEFAULT_PIN = RaspiPin.GPIO_04;
private static final int MAXTIMINGS = 85;
private int[] dht11_dat = { 0, 0, 0, 0, 0 };
private GpioPinDigitalMultipurpose dht11Pin;
private static final Logger LOGGER = LogManager.getLogger(DHT11.class
        .getName());

public DHT11() {
    final GpioController gpio = GpioFactory.getInstance();
    dht11Pin = gpio.provisionDigitalMultipurposePin(DEFAULT_PIN,
            PinMode.DIGITAL_INPUT, PinPullResistance.PULL_UP);
}

public DHT11(int pin) {
    final GpioController gpio = GpioFactory.getInstance();
    dht11Pin = gpio.provisionDigitalMultipurposePin(LibPins.getPin(pin),
            PinMode.DIGITAL_INPUT, PinPullResistance.PULL_UP);
}

public double getTemperature() {
    PinState laststate = PinState.HIGH;
    int j = 0;
    dht11_dat[0] = dht11_dat[1] = dht11_dat[2] = dht11_dat[3] = dht11_dat[4] = 0;
    StringBuilder value = new StringBuilder();
    try {

        dht11Pin.setMode(PinMode.DIGITAL_OUTPUT);
        dht11Pin.low();
        Thread.sleep(18);
        dht11Pin.high();
        TimeUnit.MICROSECONDS.sleep(40);
        dht11Pin.setMode(PinMode.DIGITAL_INPUT);

        for (int i = 0; i < MAXTIMINGS; i++) {
            int counter = 0;
            while (dht11Pin.getState() == laststate) {
                counter++;
                TimeUnit.MICROSECONDS.sleep(1);
                if (counter == 255) {
                    break;
                }
            }

            laststate = dht11Pin.getState();

            if (counter == 255) {
                break;
            }

            /* ignore first 3 transitions */
            if ((i >= 4) && (i % 2 == 0)) {
                /* shove each bit into the storage bytes */
                dht11_dat[j / 8] <<= 1;
                if (counter > 16) {
                    dht11_dat[j / 8] |= 1;
                }
                j++;
            }
        }
        // check we read 40 bits (8bit x 5 ) + verify checksum in the last
        // byte
        if ((j >= 40) && checkParity()) {
            value.append(dht11_dat[2]).append(".").append(dht11_dat[3]);
            LOGGER.info("temperature value readed: " + value.toString());
        }

    } catch (InterruptedException e) {

        LOGGER.error("InterruptedException: " + e.getMessage(), e);
    }
    if (value.toString().isEmpty()) {
        value.append(-1);
    }
    return Double.parseDouble(value.toString());
}

private boolean checkParity() {
    return (dht11_dat[4] == ((dht11_dat[0] + dht11_dat[1] + dht11_dat[2] + dht11_dat[3]) & 0xFF));
}

}