There are so many different plastic cards that adults have to carry around-library cards，savings cards for different banks，credit cards，just to name a few…So why not have one to replace them all？

Scott Barnhill，an 1l-year-old fifth-grade student in the US，has come up with an idea for a"Security One Card"．

Sound smart？The US Patent（专利） Office thought so，and it approved a patent for his idea in April．

Here's an example of how Barnhill's idea would work．

Let's say you have the three cards mentioned above．Instead of carrying them all，you could have just one by having additional magnetic strips（磁条） added to it．

The magnetic strips can be added to any plastic card，even a blank one．

Companies could add their information to one of the strips．For example，you could ask a library to add a strip to your bankcard．

Barnhill has a lot of hobbies，including designing websites．He got the idea at the age of 9when he saw his father using a keycard to enter their hotel room．He thought，"The hotels are wasting money with the key cards．"So，instead of using a hotel-issued key card，guests could use their credit cards--if the hotel added a special magnetic strip．At check-out，the strip would simply be removed．

Now that he has his patent，his next step is a letter-writing campaign to get support from major credit card companies．

"I'm going to be writing letters to credit card companies to ask if they can co-operate．I hope they'll give me money every time someone puts a strip on the back of another card，or every time the idea is used，"Barnhill said．"I'll write the letters and see what they say．If they say no，I'll ask someone else，another credit card company．"

He is hoping to make money from his patent and has decided it would be better to collect royalties（专利使用费）rather than sell his patent if the idea takeoff．

"The ATM person who invented that sold