I want to use the DHT11 sensor with my Raspberry PI 2 Model B.
I'm using pin#01 for the VCC, pin#39 for GND, but I don't know which pin should I use for DATA? Should I enable some GPIO ports to use them? I get only 0x0 data (I tried pin#37).
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You don't mention what if any tutorial you are using, but have you tried this learn.adafruit.com/…– Steve RobillardDec 1, 2015 at 7:54
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Yes, I tried this Adafruit tutorial, but I get 0x0 data only.– PanthesileaDec 1, 2015 at 8:02
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1 Answer
Use any GPIO you want.
I have some example software at http://abyz.me.uk/rpi/pigpio/examples.html#pdif2_DHTXXD to read the DHT series of temperature and humidity sensors. It should auto detect the sensor type. It requires my pigpio library.
Connect Pi 3V3 to sensor +, Pi ground to sensor ground, and any GPIO to sensor data. You ALSO need to connect a 4k7 (or thereabouts) resistor between the data line and 3V3. The sensor will not work otherwise.
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Thanks! Could you tell me can I use 5V for the sensor? I read the sensor's specification and it says if I use 5V I can send the signal to 20m, which is great because I want to deploy other sensors inside the house. Dec 1, 2015 at 20:19
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It should be possible to do as follows: Connect Pi 5V to sensor +, Pi ground to sensor ground, and any GPIO to sensor data. You ALSO need to connect a 4k7 (or thereabouts) resistor between the data line and 3V3. In other words leave the data line pull-up connected to 3V3 but power from 5V. I have not tested this but I'm told it will work by those who know more than me.– joanDec 1, 2015 at 20:38
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So I can use 5V too. Should I use other resistor? And can I use multiple sensors with sharing the 3.3/5V and ground and separating data lines for each sensor? Dec 2, 2015 at 12:45
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@Panthesilea The same value resistor will be fine. You can share the power and ground lines between sensors. You will need a separate resistor for each data line pull-up to 3V3, and each data line will need its own GPIO.– joanDec 2, 2015 at 12:50