Using instance ID as A member ID

[Xiphware]

@godlove

But I need a Simplest ID not complecated couse we use this ID to label blood sample tubes for futher investigation.

If the UUID string returned by the usual ODK function uuid() is too complicated, you can pass the function a length parameter to generate a shorter GUID, eg uuid(4) [with corresponding less guaranteed 'uniqueness'...]. See uuid() for details.