To ensure the best result in Data Collection, it is best to record with a MicroSD card that has a capacity no less than 128 GB of storage.
Here is an example of what they look like:
We strongly recommend using cards of at least this size, as a typical day of data collection could use upwards of 50 GB.
With this in mind, a 128 GB MicroSD card is large enough to hold approximately 2 days of collected data.
When you are recording with the RoadSense Application it will denote, in the bottom left, the available space/time remaining.
Space on the card/device will free up after uploading the data.
This is a LINK to an article from Samsung that shows you how to correctly insert a MicroSD card into the Samsung S9 device: https://www.samsung.com/ca/support/mobile-devices/how-do-i-insert-microsd-card-into-galaxy-s9-or-remove-it/