Dew heater control
The HBG3 provides two channels of Smart Dew Heater Control functionality, using an optional SHT30 ambient sensor for temperature and humidity and thermistor inputs from (eg.) the Celestron Dew Ring accessories. The current dew point and thermistors are continuously monitored and the dew heater outputs are adjusted to maintain just the right amount of heat to prevent fogging up.
A small bit of extra hardware and separate 12V supply is necessary for actually driving the high current 12V output to the Dew Heaters.
The Dew Heater functionality provides a faithful emulation of the Celestron 2X DewHeater Controller, enabling monitoring and control from Celestron Hand-Controllers and also from CPWI software on a computer.