A wireless keyboard allows a user to operate a computer at distances greater than is possible with a corded keyboard. Wireless keyboards can be quite useful in home multimedia entertainment centres where a computer is connected to a television set, providing the freedom to use the keyboard from any seating location. Converting a USB corded keyboard to wireless is possible with the correct equipment, time and knowledge of what is necessary to make the wireless connection work.
Turn off your computer and disconnect the power.
Remove the corded USB keyboard from the computer's USB port.
Connect one micro-controller to the keyboard's USB port. Atmel Atmega micro-controllers are very suitable for this purpose but any type of micro-controller can be used provided that it can be powered by an internal battery and is USB compatible. The micro-controller needs to be loaded with the USB protocol; it can be purchased with the USB protocol already loaded or it can be loaded manually if desired.
Connect the radio transmitter to the micro-controller that is attached to the keyboard. The micro-controller and the radio transmitter have designated interfaces for this connection. The transmitter should be configured to transmit at 433.92MHz. Radiotronix offers a wide range of transmitters suitable for this type of use. The transmitter must be powered by an internal battery.
Connect the second micro-controller to an available USB port on the computer. This micro-controller can be powered either by an internal battery or external power as the unit will remain stationary during use.
Connect the second radio transmitter to the micro-controller attached to the computer. The transmitter should transmit at 433.92MHz. This micro-controller can be powered by an internal battery or external power as the unit will remain stationary during use.
Turn on both micro-controllers and both radio transmitters.
Connect power to the computer and restart the PC.
Use the wireless keyboard as you would a corded keyboard. Once the computer restarts, the wireless keyboard should work automatically. If prompted by the operating system to load drivers for a new device, use the device drivers on the CD that came with the keyboard. The drivers will be the same because the USB protocol is still being used to control the keyboard. The only change is that the data is being transmitted wirelessly now rather than through a USB cable.
Building a wireless keyboard in this manner can be expensive. You can purchase a "plug and play" wireless keyboard at a significantly lower cost than you will spend converting a corded keyboard to wireless. However, some users are very attached to their keyboards and if a particular model isn't available with a wireless option, and no other wireless keyboard is a suitable substitute, this method can provide the wireless functionality desired.