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Wireless Keyboard

Designed and Produced by: Luke Hejnar and Sean Leventhal (Spring 2003)

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Introduction:
For our project, we designed a wireless keyboard that uses RF to transmit signals to the computer. In our design, we use a regular, 102 key ps/2 keyboard and connect it to our transmitter circuit. On the computers side, we connect our receiver circuit to the ps/2 port on the back of the computer. With this set up, we convert a cheap ordinary keyboard into a wireless keyboard.
We had several motives for choosing this project. First of all, computers have lots of wires and cables connected to them. These include the power cable, the monitor cable, the printer cable, network cable, speaker wire, microphone input, modem lines, various USB device and the essential mouse and keyboard wires. These wires form an unsightly tangled mess in the back of all computers. We therefore chose to eliminate one of these wires by making a wireless keyboard. Second, the trend for making wireless devices continues to increase. These days, we have wireless remote controls for TVs, VCRs, stereo systems, car alarms and garage door openers. Furthermore, we have wireless telephones, network connections and the now ubiquitous cell phones. We even have wireless remote controls for floor fans. Since wireless devices are becoming so popular, we decided to make a wireless device so that we could learn more about such devices. Furthermore, we decided to make a wireless keyboard because current wireless keyboards are either too expensive or have a fairly short range. For example, most current wireless keyboards use infrared for communication, which limits their range to about 6ft. These keyboards cost about $40. Some newer keyboards that use RF have a longer range, but these keyboards often cost twice as much or more. Finally, we had a need for a cheap wireless keyboard with a long range: Sean enjoys playing movies on his computer but watching them on his TV. To do this, he runs a long wire from his video card to the TV. However, if he wants to pause or rewind the movie, he needs to get up and go to his computer’s keyboard and hit the appropriate buttons. Although he has an infrared wireless keyboard, the range is only about 6 feet, which is too short a distance for him. So, being electrical engineers, we decided to make a cheap wireless keyboard with a longer range.