sht21.py # read single SHT21 humidity+temperature sensor using raspberry pi
sht21_relay.py # read single SHT21 humidity+temperature sensor using raspberry pi, send interlock using Raspberry_Pi_Relay_Board_v1.0
sht21_relay_multi.py # read multiple SHT21 humidity+temperature sensors using raspberry pi, selected by GPIO, send interlock using Raspberry_Pi_Relay_Board_v1.0