For those of you that have a wireless keyboard laying around, you might be tempted to turn it into something else, like a wireless MAME controller. For those not familiar with it, MAME stands for “Multiple Arcade Machine Emulator” and is generally used to run older arcade games on a computer.
Encoders are available for this purpose, however, intending to save some money, and having an unused wireless keyboard, I decided to try to make one myself. As far as I know there are no wireless encoders available for this purpose, so that was part of the motivation for trying this.
In this post I go over my mechanical design for the cabinet as well as the electrical process of going from keyboard to MAME controller. I did eventually get the thing working, but if more than a couple buttons were pressed simultaneously, some presses were omitted. The conclusion I eventually came to was that it was better to use an encoder to control everything. Not wireless, but much more reliable. If I absolutely needed a wireless controller in the future, I would think modding an actual wireless controller (or two) in a similar manner would have worked better for my purposes.

http://hackaday.com/2011/09/27/turn-...me-controller/