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practicalarduino / SHT1x

Arduino library to support SHT1x-series (SHT10, SHT11, SHT15) temperature / humidity sensors from Sensirion
http://www.practicalarduino.com/
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SHT1x on 3.3v Motino fails #8

Open zippy opened 10 years ago

zippy commented 10 years ago

I've been trying to get an SHT10 to work on a moteino (http://lowpowerlab.com/moteino/) which works at 3.3v and 8Mhz, but the readings all come back weird (-40c,-40f, and -4.6%). Is there something that needs to be done to make it work in that setting?

giuliotamberi commented 8 years ago

If the Sensirion sensor SHt1x or SHT7x is supplied with a VDD = 3.3V, then you need to use a different conversion coefficient D1 in formula to convert the digital readout (SOT) to the temperature value. Interpolating the D1 coefficient values listed in the Sensirion datasheet table 8, the linear interpolated values to be used in the .cpp file are:

In case of degrees Celsius readTemperatureC() const float D1 = -39.66; // for 14 Bit @ 3.3V

In case of degrees Fahrenheit readTemperatureF() const float D1 = -39.42; // for 14 Bit @ 3.3V

Also, consider to use the new otimised coefficients introducted in Dec 2011 by Sensirion: https://github.com/practicalarduino/SHT1x/issues/7

Ciao, Giulio https://twitter.com/giuliotamberi