Scott Penrose


Scott is an expert software developer with over 30 years experience, specialising in education, automation and remote data.

SHT1x (SHT10, SHT11, SHT15) are good and reasonably cheap temperature and humidity sensors that have been around for a while.

Connecting them up recently to a Teensy 3.1 I could not get it to work.

After spending a few hours working through my logic analyser, checking why it worked with an AVR Arduino Mega but not the Teensy I assumed it was timing and spent a while fixing the shiftIn, shiftOut and delays used in the library.

Still... nothing.

Turns out, I was powering it with 5 volts - chips accepts 2.5 to 5.5 volts - no worries right. Except my logic pins (clock and data) are output at 3.3 volts. Normally this does not matter. Moved to 3.3 Volts power - everything works.

Returned all my code to defaults and they all worked ! I can confirm that the following libraries work:

The later library has the advantage of providing a non blocking method of reading temperature and humidity. Although turns out I don't need it so I am using John's version (practical arduino).

  • Arduino
  • Teensy