SHT11 Temperature & Humidity Sensor Interface

Common
The SHT11 is a temperature and relative humidity sensor module comprising a calibrated digital output. The sensor has a 2-wire serial interface. By adding a few extra components the SHT11 can interface with a normal RS-232C port, like the PC serial ports. The SHT11 is supplied in a SMD LCC package. The described interface connects to a serial port of the PC. The SHT11 sensor is manufactured by Sensirion.

Interface
The interface is easy to build. It consist of a few resistors and zener diodes. The hardest part is to solder the SHT11 sensor. The Visual Basic application reads from the SHT11 sensor the digital word and calculates the Temperature, Relative Humidity and the Dewpoint.

Release History

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 v2.0 
 Option Log File Output added to the Log File menu. It is now possible to generate a .txt or .html log file.
  

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 v1.5
 Log File option added.
 

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 v1.4
 Options menu Interval option added. Interval can be set to 1, 3, 5 or 10 seconds between
 each measurement.
 

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 v1.3
 Options menu Reset option added. Sometimes the SHT11 sensor is locked. By giving a reset
 pulse the sensor will be reset and initialized.
 

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 v1.1 and v1.2
 Both releases are bug release. Mostly timing problems were solved.
 

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 v1.0
 Initial release of the SHT11 Temperature & Humidity Sensor Interface.   
 

Screenshots

Schematic

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