By Markus Hirsch (Germany)
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To the average e-enthusiast, the RS232 interface always appears friendlier than the USB port. However, with a small 8-bit microcontroller, nowadays it's possible to implement the USB bus in device mode. The advantages are obvious. First, you save the cost of a USB/RS232 converter. Then, USB devices such as keyboards can be easily emulated without needing a separate driver, meaning you are able to design a programmable USB keyboard at minimum hardware cost and software effort. And as you will discover here, our versatile USB Keyboard Stick not only helps to build useful designs—it’s also fun to use by itself!