Before deciding on the PIR detectors that I would use for the motion detection I felt that it would be sensible to consider how the signal could be sent from the PIR detector to the computer once motion had been detected. During another module from CMP I had worked with IPAC cards, which were cards that could be plugged into a computer to replicate a keyboard. From this different sensory equipment could be plugged in and then converted to a 'keypress'. Although in this instance an IPAC would not be suitable considering electric current etc, I assumed that there would be a more advanced option available that would be able to handle the several different PIR detectors. After initial searches I found several tutorials that guided you through circuitry that would allow you to convert your PC into a home security system, but none that led me to a simple hardware solution. I decided the next step would be to search the shops where equipment like this may be found. Fortunately Maplin stock a USB Experiment Interface Board, which works extremely well for home automation.
The board has 5 digital inputs and 8 digital output channel and can plug directly into the PC via USB. The board also came with its own software, but was also compatible with visual basic, which I could use to control the project through the board. The board was also a good choice as four could be used at the same time, which would enable for anything up to 20 inputs and 32 outputs. Although I was confidant that I would not need this many, it was reassuring to know that the option was there.
Each board costs £34.99 ready assembled.
As well as the board I decided to purchase some flexible wire, as I was certain that I would soon need to wire the board to PIR detectors, and would need it for later in the project. I bought 100m of red wire and 100m of black, which would allow me to colour code positive and negative connections.
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