Yes It does matter. It should be set to Arduino as ISP. Thanks for pointing that mistake out!
Programming the ATTINY85 ChipView Instructable »
Simple Camera Slider Electr...View Instructable »
Thanks you,"retro-reflective tape" I had to google that one. Very good idea!I had pondered about the ambient light, hence the two photo resistors. Very good idea with the pulsing. (Will do some testing on the photo-resistors ability to detect changes with a pulsed laser).
Arduino Laser TripwireView Instructable »