Fixes and improvements

• Fix device reporting NaN after entering sleep intermittently
• Cleanup sleep enter.
• Add median filter to Battery ADC
• Improved Home Assistant integration

esphome + new ppm model

• Move firmware to esphome.
• Use latest ppm model
• Expose calibration parameters to Home Assistant UI
• Reduce deep sleep to a minimum to increase sampling rate

Solar panel + faster sensor updates

• With the installation of Solar panel, sampling frequency increased to every 15 minutes.
• Fixed Home Assistant Warning.

Combine pH and ORP for Free Bromine ppm estimate

• Free bromine prediction model packaged as tflite micro
• More documentation