I have an Arduino Uno and A Raspberry Pi B+. I was wandering how I could use either as a Programbel HID Device (EX: https://srlabs.de/badusb/). The Reason I ask under the arduino section is I want to preferably use it. If not I can use either.
There are several arduino compatible boards that do can act as a HID device natively. Most boards built around the ATMega32u4 can be a HID device. For example the Arduino Micro
See this question about the Raspberry Pi.