sschober / dht22

small tool for reading temperature and humidity with the dht22 sensor on a banana pi

Read Humidity and Temperature with DHT22 Sensor

dht22 is a small daemon, if you like, that continuously aquires humidity and temperature readings at configurable intervals and prints these to stdout and to a file called log.csv in the current working directory. Each line therein is formatted as follows:

<YYYY-MM-DD>;<HH:MM:SS>;kk.k;ll.l

With k being a digit of a humidity reading and l corespondingly being a digit of a temperature reading. A sample line might look like the following:

2017-12-10;15:17:31;51.1;20.7

Here, a humidity of 50.1% and a temperature of 20.7C was read on 10. decembre 2017 at 15:17:31.

Invocation

dht22 can be invoked as following:

dht22 [<read delay in ms> [<number of retries> [<retry delay in ms]]]

A sample invocation might look like this:

dht22

Which would trigger default values for read and retry delay and number of retries. Another sample invocation might be:

dht22 60000 10 600

which would try to aquire a reading every minute, with 3 retries and a retry delay of 600ms.

Build

Just the usual

make

should suffice.

Author

The code is heavily inspired by various sources found on the net and tweaked a bit by me.

Sven Schober sv3sch@gmail