Photoresister sensor with MQTT

Enables attaching a photoresistor sensor like the KY-018 and publishing the readings as a percentage, via MQTT. The frequency of MQTT messages is user definable. A threshold value can be set so significant changes in the readings are published immediately vice waiting for the next update. This was found to be a good compromise between excessive MQTT traffic and delayed updates.

I also found it useful to limit the frequency of analog pin reads, otherwise the board hangs.

This usermod has only been tested with the KY-018 sensor though it should work for any other analog pin sensor. Note: this does not control the LED strip directly, it only publishes MQTT readings for use with other integrations like Home Assistant.

Installation

Copy and replace the file usermod.cpp in wled00 directory.