First heed what John mentions. That said reading the
si1142 IR Slider Demo Kit User's Guide there are a few caveats you should be aware of. Enough caveats to make me recant some of my original thinking.
The kit is built around two main pieces of hardware, the IR Sensor portion and the uC (micro-controller.
This is a link to the uC they use made by them. Should the embedded link not work then a simple Google of "c8051f800" will find the pdf on the uC.
My understanding is the kit itself gets you the uC with a basic loaded program. Reading my first link they will be happy to sell you anything and everything else for additional programming. Thus, the caveat. I suggest you read the IR Slider Demo Kit User's Guide with a focus on software. Enter all of the "optional tools" which are pretty much needed.
Based on your post here is what I suggest you try doing. There are a dozen or more little uC kits out there that teach you micro controller basics. There are no shortage of assorted sensors out there that can easily work with micro controllers. There is also no shortage of analog/digital IO kits out there that will work with sensors doing just about anything you could want. I would begin looking in those directions as it would seem much more open and cost feasible.
For example I can go to a local brick and mortar shop and buy for example a Velleman® K8048 PIC® Programmer & Experiment Board or a Velleman® K8055 USB Experiment Interface Board Kit, including my local Radio Shack of all places as well as a host of online suppliers. The latter not being a bad little kit for the cost.
This forum also has a very good micro controller section with many really knowledgeable people. The question becomes do you have any programming skills?
Ron