Hello, I am interested in developing this program. I must admit, I have never done anything like this. Despite that, I have an excellent knowledge of Java and I know it could be done fairly not that hard. Although Java doesn't officially support usb connections, but there are few libraries that do that, so sending messages and receiving data streams wont be a problem. I must point out a problem here, knowing that you and I live in different continents, you could not provide me with handheld and transmitters, but I can suggest a fair tactic. I do my research and program an app that should work, and then test it via your computer with connected receiver by using teamviewer. I think that would be an optimal way to solve this problem. Again, I haven't done this kind of project, but I'm sure I can do it and meet the deadline. If you choose me and I fail to deliver you can get a full refund of the milestone, I won't dispute. Think about my offer, if you like what you read feel free to message me. Good luck.