How to know if Temperature and humidity sensor DHT11 is working. I am trying to read data from DHT11, when I read data using Adafruit library it just keeps waiting for data.
When I tried using https://github.com/szazo/DHT11_Python it gives me error code 1, which means missing data.
Please help me out.
I suggest you try with my example DHTXX code.
Extract the zip to a directory and then compile/link with
gcc -Wall -pthread -o DHTXXD test_DHTXXD.c DHTXXD.c -lpigpiod_if2
The start the daemon
sudo pigpiod
and run the code
/DHTXXD -g4 # assuming you are using Broadcom GPIO 4
pigpio is pre-installed on recent Raspbians, otherwise try sudo apt-get install pigpio or see http://abyz.me.uk/rpi/pigpio/download.html
And with that, 3 days latter - dead. More research on the web says that the DTH22 will sometimes hang and the solution is to power cycle. From a python code I had run across they had used another GPIO pin to power the chip and not pin 1 (3v3). Original wiring was pins 1, 7, 9. I've moved the 3v to pin 11 GPIO-17.
Side story: My RasPi controls my hydroponic greenhouse - heating/cooling, watering, feeding a DB (graph of temps etc). Depending on the temperature the Pi sends an X10 signal to On/Off a 1500W space heater or to run a wet wall and exhaust fan. So: A) imperative that temperature reading be available at all time - fear of freezing or over heat, and B) I'm anal.
So, once a minute gtemp.php runs. (among other things) exec("DHTXXD", $th); then if temp = 32 and humd = 0 (@$!#@ sensor is hung) then:
system("gpio -g mode 17 out"); system("gpio -g write 17 0"); system("gpio -g write 17 1"); rerun DHTXXD (and send me an txt saying so)
