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SmartThermo

Official Description

SmartThermo - external thermometer for your Android device

How simple can an external thermometer for your Android device be? This solution only needs:
1) an Android 2.2 or higher device having a stereo headphone output (and mono microphone input)
2) a Do-It-Yourself (DIY) thermal sensor kit (see details on this DIY sensor below)

Features:
-Temperature range: -50 to +180 °C (degree Celsius)
-Precision: 1 °C (degree Celsius) between -10...+30 degree, otherwise 2°C
-Fahrenheit or Celsius
-For all Android 2.2 or higher devices having a stereo headphone output
-Simple to build
-No external power needed

What can you do with this external Android thermometer sensor?

Examples:
-Send an SMS/email message if temperature falls below or above a certain value, or if power is lost, or if sensor is not working anymore

How to build the DIY sensor?
-See http://grauonline.de/wordpress/?page_id=297 how to build your sensor.
-For a DIY kit, see https://www.marotronics.de/index.php?a=120