Adafruit_DHT no longer works
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Adafruit_DHT no longer works

by jheo on Wed Feb 27, 2013 3:15 am

I bought a DHT sensor with rpi a few weeks ago and have been using it without problem so far. But today it stopped working. When I run Adafruit_DHT, it just hangs. I tried with other GPIOs, but it hangs. What should I do to find whether the sensor is defective?
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Re: Adafruit_DHT no longer works

by adafruit_support_bill on Wed Feb 27, 2013 7:22 am

Is this on a breadboard? Re-seat all your connections and make sure they are secure.
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Re: Adafruit_DHT no longer works

by jheo on Wed Feb 27, 2013 9:43 pm

I confirmed it's well connected in several ways. I've checked with strace. In the Adafruit_DHT.c, the following part is hanging.

// wait for pin to drop?
while (bcm2835_gpio_lev(pin) == 1) {
usleep(1);
}

Any insight?
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Re: Adafruit_DHT no longer works

by adafruit_support_rick on Thu Feb 28, 2013 7:14 am

Use a multimeter to double-check for continuity between the DHT pin and the cobbler gpio pin. If that rings out, then you've probably got a bad DHT. Email support@adafruit.com with a link to this thread and ask for a replacement.

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Re: Adafruit_DHT no longer works

by jheo on Thu Feb 28, 2013 9:52 am

I'll check the sensor this evening again, and will contact the support.

Could you recommend a stable temperature sensor for RPi? I am measuring room temperature every 5 minutes. I found many people have trouble with DHT22. Maybe I would need to consider using a better sensor.
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Re: Adafruit_DHT no longer works

by adafruit_support_rick on Thu Feb 28, 2013 11:33 am

Try a digital sensor, like the DS18B20:
We have a tutorial for using it with the Pi.

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