From EngineHub.org Wiki
The MC1262 checks to see if the light level of the block above the IC sign (probably intended to be the block above the block behind the IC sign) is greater than or equal to a configurable threshold whenever the input goes from low to high.
Warning: This sensor requires a clock input and will not check on its own. Use MC0262, the self-triggering version, if you want the detection to be automatic.
- Third line: Minimum light level, 0 to 15.
|Redstone ore (when touched)||9|
|Lit redstone torch||7|
- High if the threshold is reached