You can unluck the bike very easily with the mobile phone, by sending a SMS to the number on the lock. 

It is possible to unlock the bike with the app if you have an Iphone or an Android smartphone. First of all, you must have a valid account and you have to download the App.

It is also possible to rent a bike with a special card. This card looks like a credit card and contains a chip. The chip can read who you are and if the card is still valid.