Add support for switches using an AC detection circuitry

[halfbakery]

Description:

MOES MS-104B and many of its clones (mine is a BlitzWolf SS5 2 gang) using an AC detection circuitry to emulate switches. This circuit generates a ~4 ms long LOW pulse in every AC period if the external switch is pressed.

My solution is to use the switch debouncing code to detect these AC pulses, so these switches can work almost out-of-the-box. The SwitchDebounce parameter controls the AC detection. If the last digit is 9, it will activate the AC detection code. The other part of the parameter behaves exactly as expected: e.g. 69 means 60 msec debounce time (60 msec / (1 / 50 Hz) -> 3 pulses).

I wanted to be as non-intrusive as possible, so I kept the polling code, but I had to call it 5x faster to detect pulses (of course only if AC detection is requested).

Checklist:

• The pull request is done against the latest dev branch
• Only relevant files were touched
• Only one feature/fix was added per PR.
• The code change is tested and works on core ESP8266 V.2.7.1
• The code change is tested and works on core ESP32 V.1.12.2
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass

[discip]

@halfbakery
Good evening,
thank you for this PR.
Could you please help me out with this?
Because I can't manage to understand, how to setup this device, to make use of the external switches/push buttons.

thank you in advance
kind regards

[ascillato]

Please, address this to the Tasmota Support Chat. The chat is a better and more dynamic channel for helping you. Github issues are meant for Tasmota Software Bug Reporting.

Please check the Contributing Guideline and Policy and the Support Guide.

Thanks.

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[halfbakery]

I hope the documentation will be updated soon. Here's the relevant patch:
https://github.com/tasmota/docs/pull/355/files

[blakadder]

It being updated right now :D

[discip]

@halfbakery, @ascillato & @blakadder

Thank you very much.