SHTxx humidity sensor shows too little RH?
Compare the temperature to calibrated reference. The humidity sensor may be warmer than environment. Check for heat sources. Remove anything causing a temperature gradient between the humidity sensor and the air to be measured. back to top 23. Clean POWER ON of the SHTxx It is important that the SHTxx be powered up cleanly or it may lockup and not respond to commands. This can be caused by a combination of three factors: 1. A possibility that voltage at VDD rises very slowly during power up (typically VDD rises slower than within 50 ms to 90% of its target value). 2. Spikes are present on the power supply during the power-up phase. 3. SCK is floating or held high during power up. To ensure that power-up is clean, the following precautions should be taken: 1. Power supply pins (VDD, GND) should be decoupled with a .01uF capacitor to improve the supply voltage integrity during the power-up phase. 2. If it cannot be guaranteed that the SCK line is low on power up, add a 10k pulldown resis