Hi, I am looking for an app or a program which can count how many time a patron use an information center.  The purpose of the app/prog is to find out a person's usage on the information center. We do not want to record what he/she uses, but would like to know the head count.  I could write my own, but if there is one hosted with reasonable cost, it will be better. 

The requirements are:
1. When a user come to the center, a staff will scan his/her card (with QR or other barcode) 
2. The app/program record the person's info with current timestamp. 
3. The app can do some statistic calculation on the data (e.g. how many times does a user come to the center? How many users use the center in a day, a month, a quote  )
4. It is probably easier to have this app/program hosted by a company with minimal cost. 

Any recommendations? 

Many thanks in advance,