Industrial style 8ch low power dimmer with 24V power supply, DIN rail box, 8 analog inputs and Modbus (RS485) interface. Classic dimming schematic based on triacs and optocouplers. Control logic implemented with single Atmega328.
Zero Crossing Detector (ZCD) is needed to control dimming.
Triacs as switching devices connected via optocouplers
Atmega controls dimming
Each triac can be controlled by voltage level on analog inputs (0..10V) or using the external controller
The resistors limit a current and the diodes limit a voltage from the bridge. RC output filter reduces the noise from mains. Both outputs from RC filters must be connected to Atmega's comparator. Such schematic uses two pins of Atmega.