- 4x16 LCD display
- RTC module for timekeeping
- High power led lighting, with PWM ramp-up and ramp-down at set times.
- Mains relay for switching air pump on and off at set times.
- 12V solenoid valve for switching CO2 on and off at set times.
- Solenoid driven at full power briefly to switch, then held at a lower current to reduce power consumption and avoid overheating the coil.
The schematic can be copied & edited here