How to get the accurate temperature readings from DHT11 sensor on GrovePi+?

Question

I am using DHT11 and GrovePi+ shield with Pi 2 running Raspbian Jessie.

The following is the function call for the sensor to fetch current humidity and temperature

[ temp,hum ] = dht(dht_sensor_port,0)

The problem is that it returns only the values before decimal. The values after decimal are truncated to 0.

Please do let me know if I am missing anything or the sensor needs to be replaced with a DHT22.

joan · Accepted Answer · 2016-05-12 13:58:06Z

3

The DHT11 only returns degrees and quotes an accuracy of +/- 2 degrees.

The DHT22 returns tenths of a degree and quotes an accuracy of +/- 0.2 degrees.

The source for this information is the widely available datasheets.

answered May 12, 2016 at 13:58

joan

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And based on my experience, the DHT11 humidity is not even that accurate, at least without proper calibration.
– DimP
Commented May 12, 2016 at 18:08
@DimP That's my experience as well, see raspberrypi.org/forums/viewtopic.php?p=952398#p952398
– joan
Commented May 12, 2016 at 18:56

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