Sound in Decibel. Decibel Level: 0-20dB, Description: silence, with hardly any audible sound , Harm: none; 20-40dB, Description: quiet murmur, Harm: none ; 40-60dB, Description: normal indoor conversation, Harm: none; 60-70dB, Description: clamor, l

ESP8266 NodeMCU Lua 1.0 with DHT11/22

pm10 pm25 temp hum ppmv

ultrasonic-SR04 with esp8266 from 234(1-N)