wookookie / dht22 Goto Github PK

@ccoong7, finally I found a code that works with my DHT22.
I used to use the Adafruit python library but that needs to much resources on my ZeroW with RPi camera. Your code need almost no resources. Thumbs up!

I would like to make some suggestions:

• include an option to spacify the pin at the command line
• include an option to export only the temperature and humidity readings in clean text for easier processing
• stop after first correct reading (on my RPi I changed your source code to include a return 0; if a reading was succesful).

I could fork and try to include my suggestions and issue a pull request. However I did not program in C for a long time....

I found that with the original code at temperatures > 25.4 degrees celsius the temperature would print 0.0 and increase further from there. Eventually when the actual temperature drops below 25.4 again it would print the temperature as expected. Some research and comparisin with other C implementation suggest a different calculation of celsius.
Changed "celsius = data[3] / 10.0;" to "celsius = (((data[2] & 0x7F)*256) + data[3]) / 10.0;" from code of Juergen Wolf-Hofer

See also my pull-requests: https://github.com/danichoi737/DHT22/pull/2/commits