How to make Break-beam digital countdown display

Well after making the subject line what else can i say…

Basically, and I mean basically, I need to wave my hand through a break-beam no longer than 1" which in return countdown from a preselected number on a 2-digit display. This preselected number would be assigned by using 2 force sensing resistors (1-up/1-down) as well as 1 to reset to the preselected number (not to zero). I need to be able to select 1-99

Also i need this to run off of a 9v or 2-AA batteries for at least an hour.
Any Ideas, or a shopping list so i can build it?



One of our digital IR distance sensors might be your best bet if you want to detect an object within a 1" range; it will simply output a high or low signal based on whether it detects an object within its sensing distance. Our force-sensing resistors can also be found in the Sensor category.

If you have experience programming microcontrollers, it should be straightforward to interface with these parts and to implement the rest of your system, but if you do not, I would recommend starting by getting a programmable controller and playing around with some code examples so you can familiarize yourself with it.

Your question is quite broad, so we might be able to give you some better answers if you narrow it down to some specific questions about parts that you are unsure about.

- Kevin