Help to decoding a string into a serie of decimal data (Jinja2 for Sigfox payload)

I can read now the payload long string from a Sigfox sensor

I’m using this ‘custom grammar’ and I don’t know how to extract, for example, the ‘5138’ substring in order to convert it to “14417” in decimal format :slight_smile:

Thank in advance you for your help to write the right Jinja2 template