One of the key reasons your SD card is not recording to your Raven is an incorrectly formatted SD card.
*Make sure to also read our minimum SD card specifications to work properly with Raven:
Raven requires that the micro SD card be formatted to the file format FAT32, in order to record to it.
To format your SD card in Raven go to your Raven Connected app after you inserted the SD card. If you see an SD card symbol warning on your Raven, go to the following view under the Raven Connected app:
SETTINGS - STORAGE
Follow the link below to learn more about formatting an SD card: