The Circuit Playground Express will need to initially plugged in for 48 hours so that the CCS811 sensor can burn in. The spec sheet suggests an additional 20 minute warmup before each use.
If you wish to see the raw data you can connect to the Circuit Playground Express micro USB connector to a computer and watch the console output. On Linux or OS/X the screen command the /dev/*modem* device is the easiest way.
Download:
file
$ ls /dev/tty.usbmodem* /dev/tty.usbmodem1421 $ screen /dev/tty.usbmodem1421 115200
The above command will show the name of your Circuit Playground Express and connect you to the console on OS/X. You will probably need to adjust the usbmodem#### numbers to match your exist device.
