Here I have personally divided up the whole sensor thing some going back a few years ago starting with a simple weather station that included temperature, wind speed and direction. I then got a bit carried away and built a "lighting strike sensor" using piezo kind of technology with a counter. Again then went to seeing what I could do with a counter. I went to installing water meters and connecting them to counters and then a rain tipping bucket using the counters. Thinking I did use an eye dropper and counted 1000 drops of water to calibrate it. Then barometric sensors, temperature and humidity sensors, light and dark sensors, piezo motion sensors, geophone sensors and PIR and microwave sensors and optical beam sensor and moisture sensors. (here using both occupancy types and regular PIR types of interior motion detection).
I have been intrigued by power and energy usage sensors but have not utilized them. I don't know if I can get used to watching these sensors clock like. Sometimes for me though its better that I do not look (personal thing?)
HV (high voltage) and LV switches are a different thing here. They are used extensively. I like that my switches today talk to each other and utilize these methods of tranport to carry over switch to switch commands. I like the fact that I can program a multitoggle or multipaddle switch to manage other switches virtually (in 3-4 way switch conversations with no wires between them). My wife is better with these switches today than I am. The switches also are little independant computers with their security, addressing and diagnostics which is really nice. I check signals between switches and between switch to controller which is a nice feature. The switches can be programmed to function independant of the controller simpled timing of events and mulitiple touch control. IE: one touch auto dims lighting to say 40%, a double touch goes to 100% and said device / switch provides live status of what its doing.
Recently here switched out my exterior low voltage 12VAC toroidal coil transformers to DIN 12VDC electric. That said I was playing with individual automated appliance type switches for each of the (5) 1000 watt toroidal transformers. I had occassional problems switching the loads on with the surge from the automated switch throwing the breakers. I have over the last few years switched out the multiple LV outdoor lighting zones to LED lighting using much less power and easier to maintain still automating the illumination; now with one switch only. The neighbor nearby took his LV LED lighting to storage batteries and solar panels which now has worked for some 3 years.
What is neat about this that you can write "automation" scripts reading the status of multiple environmental sensors and using these to talk to the HV or LV switches. I did a follow me lighting thing for my wife a while ago. The garage door thing is in a world by itself with multiple sensors integrated into the door and a bunch of if then stuff. IE: the garage door left open tickles the HA box and it will utilize text to speech to remind me that I have left the garage door open or text me that I have left it open.