Perhaps setting a "constant power" item (battery/generator, one depleteable, one always putting an on pulse every second, similar to the one second timer maybe, but have it be a half second timer?) could be used to operate equipment non stop. Also, for the logic gate idea, could be a wire layer item one could use to "route" pulses. As in, generator or battery item puts out a constant ON pulse to its connected wires, unless switched off (starts ON at world start?) and then one can add gates, which function similarly to MOSFETS (no, not by setting things around them on fire when they fail) but rather if switched on from one or two pinouts, allows signals to pass through from the other two pinouts, with some acting just like mosfets (allow signals only one way through the gated circuit, simulating the reverse high resistance by not allowing the signal to pass back. A second version could simply allow signals both ways regardless of gate / circuit orientation.) So you could set it so that if certain conditions are true or false along the way, a signal could be interrupted or its flow changed.
Some folks asked about something to either amplify or resist / delay a pulse. To maintain a pulse over the max length (I believe its 1000 right?) you'd want capacitors. To increase signal speed one could make the new items transformers. To slow it down, you'd want resistors. For those who wanted to be able to have multiple passthrough in the same tile for multiple wires, one could use a junction box, which could be made from various components and could also act as a master switch (maybe opens like a chest when right clicked so various connections could be made?)
I also +1 the idea of wiring spools. Maybe even make a chest or trough like object called a Spool Caddy. You can place several spools, choose one specific wire and a spot on the screen to anchor it, and run with it, could run a whole screen's worth before you "set" it and then start another length. Could also add another background item, called Conduit, which could be laid in long lengths (10,-20 ft?) which could be used along with a new item available from mechanic, Fish Tape to run huge lengths of cable. You use the fish tape and right click it to change colors of wire you're laying down, then use it on a length of conduit, and it lays it in the same way you run rope downwards, at similar speeds, thus reducing the need for screwy layouts. Since you'd be able to lay conduit in long sections, you could avoid a lot of headaches going through large walls, etc. Maybe requires all colors of wrench and some colored string (yoyo accessory) to make?
As for "wireless" repeater type items, that'd be great, but maybe those would require a constant "ON" signal from a battery or generator type item and only affect a certain area... (field gets reduced by blocks, gets reduced greatly by mineral/metal ore in the way, and has one or two screens or even entirety of above ground (not elevation but actually above all the dirt) line of sight range if surrounded by open air. Just like your home wireless router you got from your ISP. may be simpler for the devs to simply make it send signal anywhere with an open air (one block wide opening or wider) not surrounded by two block thick walls or thicker?
Battery items. We can have extra fun with this, but it may also just over complicate things because the power / pulse system is already so very well established, developed and working well. Still, say you make batteries out of copper/lead/tin/tungsten/gold/platinum and gel, obviously the better the metal the longer the battery can keep its circuit alive (maybe someone can mix in the idea of a mana battery they had on the equipment forum into this somehow.) Each battery stores half a night's power for one object (there is always a pulse every tick on the wire) divided further by more objects connected, or for every 100 wires of length (simulated loss from resistance) Battery gets charged by being connected to a generator or to a solar panel which only charges it during the day (no loss of power + battery always full, could have a charge/depletion meter, and charge in the same time it takes to discharge just to make things more interesting.) Any switch connected to a battery is not actuated by it, but it will turn off the battery's always existing wire pulse. To make it easier for the devs and for players, the battery could receive "on off" signals on its body and have "terminals" to which you attach signal receiving wires. It would make the signal sorting easier for everyone.
** Another idea is that batteries or generators as described could instead be used to lower the "refresh" speed of various items, statues, etc which have activation delays to have them actually operate faster or more frequently instead.
For conveyor belt ideas, these could be operated by on signal instead of simply always running and being turned on and off. Since the "pulse" concept could be used to work just like real power when operating motors, lets say per signal per a particular set of game ticks (velocity of conveyor could be set this way) lets say the conveyor moves at the set speed if pulse is received, if not it is idle/unpowered. Again this could complicate things, because the rest of the power system doesn't work that way.
I've wanted to suggest turrets (someone else beat me to that) and weapon mount/customizable turrets / tracked autonomous robot patrollers, but I got beat to that one too.
Still, my suggestion was to maybe have them wired to prioritize hostiles near "sensor" items on walls or "proximity" blocks if they are wired to the turret or if a wireless transmitter's area covers both items. (One could also wire the wireless transmitters through solid objects to create some pretty cool networks. In fact this is where this would work greatly. Perhaps for the robot patrollmen/turrets, one would require some sort of second condition besides the device being turned on/actuated on. Perhaps it would require a "power supply == yes" condition, and a battery could operate off of solar power and stay on until its timer/charge runs out, and a generator could act as a never ending no need to charge version. Obviously generator would be bulkier, harder to fit in many places, etc. Battery could be a single block just like the explosives pack. There could be a limit to these devices and how many other things they could power.
I had more ideas, but I'm tired so maybe another time?