The Mod adds devices to output or measure redstone power in different style variants. Complete documentation, feature details, credits, and community references is on the github project page here.

summary

Switches

Buttons
Levers
Normal pressure plates ("contact switches")
Shock sensitive pressure plates ("contact switches", detect when something/one falls on it)
Entity detectors (players, villages, animals, mobs, etc)
Block category detectors (e.g. "solid", "ore", "wood", "sapling", "farmland", "water" (includes ice), "liquid", etc)
Day timers (06:00 to 24:00)
Interval timers (tick based timers)
Light sensors ("auto switch" category)
Rain sensors ("auto switch" category)
Lightning sensors ("auto switch" category)
Switch-Link relays (optimized for wireless transmission)
Switch-Link receivers (optimized for wireless transmission)
Knock sensors (seismic detection of click or breaking an adjacent block)
Trapdoor switches (emit a signal and open)

Gauges

Analog / digital (show redstone power 0 to 15)
LEDs and semaphores ("indicators", show on/off)
Alarm lamps (also on/off)
Alarm sirens and bells ("sound indicators")
Sensitive glass (glass that emits light or changes color)

Style variants

"Series" are e.g. industrial, retro industrial, rustic, old fancy, glass, etc. For a pack you can configure exactly which series you like to include and exclude (makes no sense to have futuristic glass in a mystic medieval world, so only the rustic series is used).

Special features

All switches can be configured to weak/strong and inverted/not inverted with a redstone torch.
Most of the switches can be wireless linked with Ender Pearls.
Pulse duration of buttons is configurable with a Redstone dust stack.
Some switches and gauges can be colored with dye.
Some plates can react or ignore players, mobs, villagers, animals, items, etc.

Source code, mod pack integration, back ports, bug reports

Sources: Are located on the github: https://github.com/stfwi/rsgauges/.
Packs: If your mod pack is open source as well and has no installer (e.g. adding adware, bloatware or whatever), you don't need to ask and simply integrate this mod.
Bug reports: Yes, please let me know. Drop a mail or better open an issue for the repository.
Maintenance: The 1.12.2 mod version is now in maintenance state, means new features will seldom be implemented, but bugs will still be fixed if they are not small glitches.

Switches

Gauges

Style variants

Special features

Source code, mod pack integration, back ports, bug reports

Current mod list by me:

Gauges and Switches