I2C address scanner reports for the SHT21 : 'I2C Scanner
Scanning...
I2C device found at address 0x40 !
done'
when I take the SHT21 away and put the BMP280 in place, it reports:
I2C Scanner
Scanning...
I2C device found at address 0x40 !
I2C device found at address 0x76 !
done
when I connect both sensors to the Uno, I get:
I2C Scanner
Scanning...
I2C device found at address 0x40 !
I2C device found at address 0x76 !
done
the BMP280 is a breakout with as indication only 'GY21P' and of course the four pin labels VCC, GND, SCL and SDA
The SHT21 also carries the label 'SI7021'. I assume this is the temperature part of this sensor
(see attachments- pictures)
