Hi, I'm a technician maintaining lot of PC based equipment, terminals and such, on multiple locations. I often need to access the BIOS on the equipment (like when I replace the BIOS battery, I have to adjust some BIOS settings that have defaulted to wrong values) so I always have to carry a keyboard with me. I also have to carry a laptop with me, for software updates for the equipment.
To reduce the weight of my tool-case (since I sometimes have to fly to the location), and the space it takes, I was wondering if I could get an Arduino to read what I type on the laptop keyboard (like pressing Delete) and send it to a PC I'm trying to access the BIOS on. In other words, stop carrying the keyboard, just small Arduino that I'd plug into the laptop and a cable to the PC, then open a window on the laptop to send my laptop keystrokes to the PC.
Similar to this build http://arduino.cc/forum/index.php/topic,113982.0.html , only using 1 Arduino and solder in few wires, not custom PCBs and multiple processors like this guy did.
If you use an Arduino Leonardo then this supports keyboard/mouse emulation via the USB port. But you'd need some way for that to receive key strokes from the laptop. The simplest approach I can think of for that would be a second Arduino (any type) plugged into the laptop USB, with a TTL serial connection between the two Arduinos. You would need to run an application on the laptop to enable you to type to the laptop Arduino's COM port - there are plenty of options to choose from there.
There's even a simpler solution. Take an FTDI cable (or some other kind of USB2Serial adapter) and connect it to the RX/TX pins (0 and 1) of the Leonardo. Then program it so that it receives the keystroke on Serial1 and sends it to the USB as a keyboard device. This way you don't need a second Arduino, the FTDI cable take much less space.