Sadly, you can no longer register for OV-chip mobile. After a period of about a year, the OV-chip mobile trail has 15 June 2018 ended.
The underlying technology appears to be unsuitable to provide OV-chip mobile massively to all passengers.
Research shows that most of the current participants in the trial were very satisfied (87% rated it 7 or higher). The lessons learned from OV-chip mobile will be used to develop a new mobile payment method for public transport.