custom input button. little help please

[Mystic Mistro]

hi, 

 

im looking for ways to add a function key (id like to use a button like the one in the picture attached) to a computer using for example an USB interface. 

 

which can be pressed to initiate a program or interrupt a program to start a new function. 

the software side of this i don't have issues with its just to way of connecting a large button that will be readable by the computer is connected to.

 

when the button is pressed will deliver sweets by a robot within a pharmacy.

 

Thanks for any help here. 

[SovietOnion]

http://www.delcomproducts.com/productdetails.asp?partnumber=706501

 

Something like this?

[Mystic Mistro]

thats the one, nice!

 

thank you very much!