Maybe I'm blind, but I can't find a block to handle this simple function. I need a "block detector" (but not the RP2 block) that can look at the square in front of it and send a signal telling me if something's there or not. (Using DW20, but curious about any mods that might have this functionality)
Without RP2
Well there is always CC turtles. you can code them to check in front of them and then send a redstone signal out to any of its sides.