Redstone Power and EnumFacing

[jeffryfisher]

I'm trying to find an example of redstone device code that has more comments than the vanilla block classes. Unfortunately, my searches are running into haystacks of zany redstone constructions and their videos, so I am not finding help for modding. If anyone can point to a primer on coding redstone devices, I'd be grateful.

 

In particular, I am getting all turned around (literally) as I try to calculate how much power my device is receiving from its six faces. My first confusion is from vanilla devices: if one looks UP at a block above, it asks how much strong power is being provided "UP". It's as if the device wants to know how much power is being sent even further away. Shouldn't it want to know if the block UP is sending power DOWN (and block offset NORTH is sending power SOUTH etc)? Obviously I am not reading the correct meaning of one or more deobfucated names. Is this explained somewhere?

 

My second confusion is strong vs weak power. I want my device to be powered by connected wires or original source, but not by energized blocks. The magnitude of my device effect will depend on the strength of signal. I think that means I want only "strong" power, but I'm reading conflicting info on wire signals. I'm unsure what to believe (or what method to call).