Advanced Raspberry Pi: Raspbian Linux and GPIO Integration

© Warren Gay 2018

Warren GayAdvanced Raspberry Pihttps://doi.org/10.1007/978-1-4842-3948-3_22

22. DHT11 Sensor

Warren Gay¹ 

(1)

St. Catharine’s, Ontario, Canada

 

The DHT11 humidity and temperature sensor is an economical peripheral manufactured by D-Robotics UK ( www.droboticsonline.com ). It is capable of measuring relative humidity between 20 and 90% RH within the operating temperature range of 0 to 50°C with an accuracy of ±5% RH. Temperature is also measured in the range of 0 to 50°C with an accuracy of ±2°C. Both values are returned with 8-bit resolution.

This assignment is a challenge for a Linux application because of the signal timing constraints being accommodated. After the Pi initiates the sensor, the first event to be measured occurs within ...